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Webb finds surprises in Spiderweb protocluster field

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JWST Webb Spiderweb protocluster Hundreds of galaxies appear in this view, which is set against the black background of space. There are many overlapping objects at various distances. They include large, blue foreground stars, some with eight diffraction spikes, and white and pink spiral and elliptical galaxies. Numerous tiny orange dots appear throughout the scene.

Webb finds surprises in Spiderweb protocluster field

Using the NASA/ESA/CSA James Webb Space Telescope, an international team of astronomers have found new galaxies in the Spiderweb protocluster. Their characteristics shed light on the growth of galaxies in these large cosmic cities, with the finding that gravitational interactions in these dense regions are not as important as previously thought.

Hundreds of galaxies appear in this view, which is set against the black background of space. There are many overlapping objects at various distances. They include large, blue foreground stars, some with eight diffraction spikes, and white and pink spiral and elliptical galaxies. Numerous tiny orange dots appear throughout the scene.
Using the NASA/ESA/CSA James Webb Space Telescope, an international team of astronomers have found new galaxies in the Spiderweb protocluster. Their characteristics shed light on the growth of galaxies in these large cosmic cities, with the finding that gravitational interactions in these dense regions are not as important as previously thought.
With the use of Webb’s capabilities, astronomers have now sought to better understand this protocluster and to reveal new galaxies within it. Infrared radiation passes more freely through cosmic dust than visible light, which is scattered by the dust. Because Webb can see infrared light very well, scientists used it to observe regions of the Spiderweb that were previously hidden to us by cosmic dust, and to find out to what degree this dust obscures them.
This image shows the Spiderweb protocluster as seen by Webb’s NIRCam (Near-InfraRed Camera).
Credit: ESA/Webb, NASA & CSA, H. Dannerbauer

Astronomers explore galaxy populations and uncover their physical characteristics across large-scale structures to better understand the build-up of galaxies and how their environments shape their assembly. The Spiderweb protocluster is a well-studied object in the early Universe. Its light has travelled over 10 billion years to reach us, and it shows us a galaxy cluster in formation, composed of more than a hundred known galaxies.

With the use of Webb’s capabilities, astronomers have now sought to better understand this protocluster and to reveal new galaxies inside it. Infrared light passes more freely through cosmic dust than visible light, which is scattered by the dust. Because Webb can see infrared light very well, scientists used it to observe regions of the Spiderweb that were previously hidden to us by cosmic dust, and to find out to what degree this dust obscures them.

“We are observing the build-up of one the largest structures in the Universe, a city of galaxies in construction,” explained Jose M. Pérez-Martínez of the Institute of Astrophysics of the Canary Islands (Instituto de Astrofísica de Canarias) and the University of La Laguna (Universidad de La Laguna in Spain). “We know that most galaxies in local galaxy clusters (the biggest metropolises of the Universe) are old and not very active, whereas in this work we are looking at these objects during their adolescence. As this city in construction grows, their physical properties will also be affected. Now, Webb is giving us new insights into the build-up of such structures for the first time.”

This annotated image shows hundreds of galaxies appearing in this view, which is set against the black background of space. There are many overlapping objects at various distances. Dozens of galaxies are individually identified with white circles, and a large white circle in the centre of the image highlights the collection of gravitationally-bound galaxies in the field. The bottom of the image shows a close-up of seven of these central galaxies. The objects visible in the image include large, blue foreground stars, some with eight diffraction spikes, and white and pink spiral and elliptical galaxies, as well as numerous tiny orange dots that appear throughout the scene.
Using the NASA/ESA/CSA James Webb Space Telescope, an international team of astronomers have found new galaxies in the Spiderweb protocluster. Their characteristics shed light on the growth of galaxies in these large cosmic cities, with the finding that gravitational interactions in these dense regions are not as important as previously thought.
With the use of Webb’s capabilities, astronomers have now sought to better understand this protocluster and to reveal new galaxies within it. Infrared radiation passes more freely through cosmic dust than visible light, which is scattered by the dust. Because Webb can see infrared light very well, scientists used it to observe regions of the Spiderweb that were previously hidden to us by cosmic dust, and to find out to what degree this dust obscures them.
This annotated image shows the galaxy distribution in the Spiderweb protocluster as seen by Webb’s NIRCam (Near-InfraRed Camera). The galaxies are annotated by white circles, and the collection of gravitationally-bound galaxies is identified in the centre of the image. A selection of these galaxies are featured as individual close-ups at the bottom of the image.
Credit: ESA/Webb, NASA & CSA, H. Dannerbauer

Webb enabled the team to study the hydrogen gas using a powerful diagnostic tracer that cannot be studied from ground-based observations. That allowed the team to reveal new, strongly obscured galaxies belonging to the cluster and to study how much they were obscured. This was accomplished using only about 3.5 hours of Webb’s observing time.

“As expected, we found new galaxy cluster members, but we were surprised to find more than expected,” explained Rhythm Shimakawa of Waseda University in Japan. “We found that previously-known galaxy members (similar to the typical star-forming galaxies like our Milky Way galaxy) are not as obscured or dust-filled as previously expected, which also came as a surprise.”

“This can be explained by the fact that the growth of these typical galaxies is not triggered primarily by galaxy interactions or mergers that induce star-formation,” added Helmut Dannerbauer of the Institute of Astrophysics of the Canary Islands (Instituto de Astrofísica de Canarias in Spain). “We now figure this can instead be explained by star formation that is fueled through gas accumulating at different locations all across the object’s large-scale structure.”

This annotated image shows hundreds of galaxies appearing in this view, which is set against the black background of space. There are many overlapping objects at various distances. Dozens of galaxies are individually identified with white circles, and a large white circle in the centre of the image highlights the collection of gravitationally-bound galaxies in the field. The objects visible in the image include large, blue foreground stars, some with eight diffraction spikes, and white and pink spiral and elliptical galaxies, as well as numerous tiny orange dots that appear throughout the scene.
Using the NASA/ESA/CSA James Webb Space Telescope, an international team of astronomers have found new galaxies in the Spiderweb protocluster. Their characteristics shed light on the growth of galaxies in these large cosmic cities, with the finding that gravitational interactions in these dense regions are not as important as previously thought.
With the use of Webb’s capabilities, astronomers have now sought to better understand this protocluster and to reveal new galaxies within it. Infrared radiation passes more freely through cosmic dust than visible light, which is scattered by the dust. Because Webb can see infrared light very well, scientists used it to observe regions of the Spiderweb that were previously hidden to us by cosmic dust, and to find out to what degree this dust obscures them.
This annotated image shows the galaxy distribution in the Spiderweb protocluster as seen by Webb’s NIRCam (Near-InfraRed Camera). The galaxies are annotated by white circles, and the collection of gravitationally-bound galaxies is identified in the centre of the image.
Credit: ESA/Webb, NASA & CSA, H. Dannerbauer

The new results used Webb’s NIRCam observations (Cycle 1 programme #1572, PIs: H. Dannerbauer and Y. Koyama) and are featured in two papers that have been published today in the Astrophysical Journal.  The team is planning to study the (new) galaxy cluster members in more detail and confirm their existence with spectroscopic observations using Webb.

 

Press release from ESA Webb.

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The Sombrero Galaxy, or Messier 104, dazzles in new mid-infrared image from Webb

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Image of a galaxy on the black background of space. The galaxy is a very oblong, blue disk that extends from left to right at an angle (from about 10 o’clock to 5 o’clock). The galaxy has a small bright core at the centre. There is an inner disk that is clearer, with speckles of stars scattered throughout. The outer disk of the galaxy is whiteish-blue, and clumpy, like clouds in the sky. There are different coloured dots, distant galaxies, speckled among the black background of space surrounding the galaxy.

The Sombrero Galaxy, also known as Messier 104 (M104), dazzles in new mid-infrared image from Webb 

A new mid-infrared image from the NASA/ESA/CSA James Webb Space Telescope features the Sombrero galaxy, also known as Messier 104 (M104). The signature, glowing core seen in visible-light images does not shine, and instead a smooth inner disk is revealed. The sharp resolution of Webb’s MIRI (Mid-Infrared Instrument) also brings into focus details of the galaxy’s outer ring, providing insights into how the dust, an essential building block for astronomical objects in the Universe, is distributed. The galaxy’s outer ring shows intricate clumps in the infrared for the first time.

Image of a galaxy on the black background of space. The galaxy is a very oblong, blue disk that extends from left to right at an angle (from about 10 o’clock to 5 o’clock). The galaxy has a small bright core at the centre. There is an inner disk that is clearer, with speckles of stars scattered throughout. The outer disk of the galaxy is whiteish-blue, and clumpy, like clouds in the sky. There are different coloured dots, distant galaxies, speckled among the black background of space surrounding the galaxy.
The NASA/ESA/CSA James Webb Space Telescope recently imaged the Sombrero galaxy with its MIRI (Mid-Infrared Instrument), resolving the clumpy nature of the dust along the galaxy’s outer ring.
The mid-infrared light highlights the gas and dust that are part of star formation taking place among the Sombrero galaxy’s outer disk. The rings of the Sombrero galaxy produce less than one solar mass of stars per year, in comparison to the Milky Way’s roughly two solar masses a year. It’s not a particular hotbed of star formation.
The Sombrero galaxy is around 30 million light-years from Earth in the constellation Virgo.
Credit: NASA, ESA, CSA, STScI

Researchers say the clumpy nature of the dust, where MIRI detects carbon-containing molecules called polycyclic aromatic hydrocarbons, can indicate the presence of young star-forming regions. However, unlike some galaxies studied with Webb, including Messier 82, where 10 times as many stars are born as in the Milky Way galaxy, the Sombrero galaxy is not a particular hotbed of star formation. The rings of the Sombrero galaxy produce less than one solar mass of stars per year, in comparison to the Milky Way’s roughly two solar masses a year.

The supermassive black hole at the centre of the Sombrero galaxy, also known as an active galactic nucleus (AGN), is rather docile, even at a hefty 9-billion-solar masses. It’s classified as a low luminosity AGN, slowly snacking on infalling material from the galaxy, while sending off a bright, relatively small, jet.

Also within the Sombrero galaxy dwell some 2000 globular clusters, a collection of hundreds of thousands of old stars held together by gravity. This type of system serves as a pseudo laboratory for astronomers to study stars – thousands of stars within one system with the same age, but varying masses and other properties is an intriguing opportunity for comparison studies.

In the MIRI image, galaxies of varying shapes and colours litter the background of space. The different colours of these background galaxies can tell astronomers about their properties, including how far away they are.

The Sombrero galaxy is around 30 million light-years from Earth in the constellation Virgo.

Stunning images like this, and an array of discoveries in the study of exoplanets, galaxies through time, star formation, and our own Solar System, are still just the beginning. Recently, scientists from all over the world converged—virtually—to apply for observation time with Webb during its fourth year of science operations, which begins in July 2025.

A two panel image. The top image is Webb’s view of the Sombrero galaxy, the bottom image is Hubble’s view. In the Webb view, the galaxy is a very oblong, blue disk that extends from left to right at an angle (from about 10 o’clock to 5 o’clock). The galaxy has a small bright core at the centre. There is a clear inner disk that has speckles of stars scattered throughout. The outer disk of the galaxy is whiteish-blue, and clumpy, like clouds in the sky. In the Hubble view, the galaxy is an oblong, pale white disk with a glowing core over the inner disk. The outer disk is darker and clumpy.
This image compares the view of the famous Sombrero Galaxy in mid-infrared light (top) and visible light (bottom). The James Webb Space Telescope’s MIRI (Mid-Infrared Instrument) reveals the smooth inner disk of the galaxy, while the Hubble Space Telescope’s visible light image shows the large and extended glow of the central bulge of stars.
Both the Webb and Hubble images resolve the clumpy nature of the dust that makes up the Sombrero galaxy’s outer ring.
Credit: NASA, ESA, CSA, STScI, Hubble Heritage Team (STScI/AURA)

General Observer time with Webb is more competitive than ever. A record-breaking 2377 proposals were submitted by the 15 October 2024 deadline, requesting about 78,000 hours of observation time. This is an oversubscription rate, the ratio defining the observation hours requested versus the actual time available in one year of Webb’s operations, of around 9 to 1.

The proposals cover a wide array of science topics, with distant galaxies being among the most requested observation time, followed by exoplanet atmospheres, stars and stellar population, then exoplanet systems.

Press release from ESA Webb

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Hubble sees aftermath of galaxy’s scrape with Milky Way, at the Large Magellanic Cloud (LMC)

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A whitish, whirlpool-like galaxy at middle of top edge, and a tadpole-shaped structure sweeps from left to right across lower half. A label pointing to outer, left of galaxy reads “Earth.” Faint, purple haze labelled “Milky Way Halo” surrounds galaxy and stretches to graphic’s edges. The tadpole-shaped object is the Large Magellanic Cloud, or LMC, with its own halo and streaming tail. Semi-circular, progressively darker layers of purple labelled “LMC Halo” surround the LMC, which appears roughly circular, with a central, light yellow bar. Cloud-like features sprinkled with white specks surround this bar. Trailing the LMC is a large, tail-like feature labelled “Stream.” Three light blue lines point from the label “Earth” through the LMC’s halo, and to three corresponding quasars, which are off screen.

Hubble sees aftermath of galaxy’s scrape with Milky Way, at the Large Magellanic Cloud (LMC)

Encounter blew away most of smaller galaxy’s gaseous halo

Labelled “artist’s concept” at bottom right, the graphic shows a closeup of a dwarf galaxy, which appears roughly circular with a light yellow bar in the centre. Faint, blue, wispy, cloud-like features surround this yellow bar, and they are sprinkled with tiny white specks. A wide, wispy, purple arc appears to the left of the galaxy. Trailing the galaxy is a large, faint, wide, tail-like feature.
This artist’s concept shows a closeup of the Large Magellanic Cloud (LMC), a dwarf galaxy that is one of the Milky Way galaxy’s nearest neighbours. Scientists think that the LMC has just completed its closest approach to the much more massive Milky Way. This encounter has blown away most of the spherical halo of gas that surrounds the LMC. The bright purple bow shocks represent the leading edge of the LMC’s halo, which is being compressed as the Milky Way’s halo pushes back against the incoming LMC. The pressure is stripping much of the LMC’s halo and blowing it backward into a streaming tail of gas. The dwarf galaxy is cocooned within its remaining halo. An actual science image of the LMC is combined with an artist’s rendering of the galaxy’s halo.
Credit: NASA, ESA, R. Crawford (STScI)

In an epic story of survival witnessed by the NASA/ESA Hubble Space Telescope, one of our nearest galactic neighbours has crashed through the Milky Way galaxy’s gaseous halo and lived to tell the tale. But in the process, this dwarf galaxy, called the Large Magellanic Cloud (LMC), has been stripped of most of its own surrounding halo of gas. Researchers were surprised to find such an extremely small gaseous halo remaining — one around 10 times smaller than halos of other galaxies of similar mass. Still, the LMC has held onto enough of its gas to keep forming new stars. A smaller galaxy wouldn’t have survived such an encounter. This is the first time astronomers have been able to measure the size of the LMC’s halo — something they could do only with Hubble.

The Large Magellanic Cloud, also called the LMC, is one of the Milky Way galaxy’s nearest neighbours. This dwarf galaxy looms large in the southern nighttime sky at 20 times the apparent diameter of the full Moon.

Many researchers theorise that the LMC is not in orbit around our galaxy, but is just passing by. Those scientists think that the LMC has just completed its closest approach to the much more massive Milky Way. This passage has blown away most of the spherical halo of gas that surrounds the LMC.

Now, for the first time, astronomers have been able to measure the size of the LMC’s halo — something they could do only with Hubble. In a new study published in the Astrophysical Journal Letters, researchers were surprised to find that it is so extremely small — about 50 000 light-years across. That’s around 10 times smaller than the halos of other galaxies that are the same mass as the LMC. Its compactness tells the story of its encounter with the Milky Way.

“The LMC is a survivor,” said Andrew Fox of AURA/STScI for the European Space Agency in Baltimore, who was principal investigator on the observations. “Even though it’s lost a lot of its gas, it’s got enough left to keep forming new stars. So new star-forming regions can still be created. A smaller galaxy wouldn’t have lasted — there would be no gas left, just a collection of aging red stars.”

Though quite a bit the worse for wear, the LMC still retains a compact, stubby halo of gas — something that it wouldn’t have been able to hold onto gravitationally had it been less massive. The LMC is 10 percent the mass of the Milky Way.

“Because of the Milky Way’s own giant halo, the LMC’s gas is getting truncated, or quenched,” explained STScI’s Sapna Mishra, the lead author of the paper chronicling this discovery. “But even with this catastrophic interaction with the Milky Way, the LMC is able to retain 10 percent of its halo because of its high mass.”

A whitish, whirlpool-like galaxy at middle of top edge, and a tadpole-shaped structure sweeps from left to right across lower half. A label pointing to outer, left of galaxy reads “Earth.” Faint, purple haze labelled “Milky Way Halo” surrounds galaxy and stretches to graphic’s edges. The tadpole-shaped object is the Large Magellanic Cloud, or LMC, with its own halo and streaming tail. Semi-circular, progressively darker layers of purple labelled “LMC Halo” surround the LMC, which appears roughly circular, with a central, light yellow bar. Cloud-like features sprinkled with white specks surround this bar. Trailing the LMC is a large, tail-like feature labelled “Stream.” Three light blue lines point from the label “Earth” through the LMC’s halo, and to three corresponding quasars, which are off screen.
This artist’s concept shows the Large Magellanic Cloud, or LMC, in the foreground as it passes through the gaseous halo of the much more massive Milky Way galaxy. The encounter has blown away most of the spherical halo of gas that surrounds the LMC, as illustrated by the trailing gas stream reminiscent of a comet’s tail. Still, a compact halo remains, and scientists do not expect this residual halo to be lost. The team surveyed the halo by using the background light of 28 quasars, an exceptionally bright type of active galactic nucleus that shines across the Universe like a lighthouse beacon. Their light allows scientists to ‘see’ the intervening halo gas indirectly through the absorption of the background light. The lines represent the Hubble Space Telescope’s view from its orbit around Earth to the distant quasars through the LMC’s gas.
Credit: NASA, ESA, R. Crawford (STScI)

A gigantic hair dryer

Most of the LMC’s halo was blown away by a phenomenon called ram-pressure stripping. The dense environment of the Milky Way pushes back against the incoming LMC and creates a wake of gas trailing the dwarf galaxy — like the tail of a comet.

“I like to think of the Milky Way as this giant hairdryer, and it’s blowing gas off the LMC as it comes into us,” said Fox. “The Milky Way is pushing back so forcefully that the ram pressure has stripped off most of the original mass of the LMC’s halo. There’s only a little bit left, and it’s this small, compact leftover that we’re seeing now.”

As the ram pressure pushes away much of the LMC’s halo, the gas slows down and eventually will rain into the Milky Way. But because the LMC has just passed its closest approach to the Milky Way and is moving outward into deep space again, scientists do not expect the whole halo will be lost.

Only with Hubble

To conduct this study, the research team analysed ultraviolet observations from the Mikulski Archive for Space Telescopes at STScI. Most ultraviolet light is blocked by Earth’s atmosphere, so it cannot be observed with ground-based telescopes. Hubble is currently the only space telescope that is tuned to detect these wavelengths of light, so this study was only possible with Hubble.

The team surveyed the halo by using the background light of 28 bright quasars. The brightest type of active galactic nucleus, quasars are believed to be powered by supermassive black holes. Shining like lighthouse beacons, they allow scientists to ‘see’ the intervening halo gas indirectly through the absorption of the background light. Quasars reside throughout the Universe at extreme distances from our galaxy.

The scientists used data from Hubble’s Cosmic Origins Spectrograph (COS) to detect the presence of the halo gas by the way it absorbs certain colours of light from background quasars. A spectrograph breaks light into its component wavelengths to reveal clues to the object’s state, temperature, speed, quantity, distance, and composition. With COS, they measured the velocity of the gas around the LMC, which allowed them to determine the size of the halo.

Because of its mass and proximity to the Milky Way, the LMC is a unique astrophysics laboratory. Seeing the LMC’s interplay with our galaxy helps scientists understand what happened in the early Universe, when galaxies were closer together. It also shows just how messy and complicated the process of galaxy interaction is.

“This is a fantastic example of the cutting-edge science still being enabled by Hubble’s unique capabilities,” said Professor Carole Mundell, Director of Science at the European Space Agency. “This result gives us precious new insights into the complex history of the Milky Way and its nearby satellite galaxies.”

Looking to the future

The team will next study the front side of the LMC’s halo, an area that has not yet been explored.

“In this new programme, we are going to probe five sightlines in the region where the LMC’s halo and the Milky Way’s halo are colliding,” said co-author Scott Lucchini of the Center for Astrophysics | Harvard & Smithsonian. “This is the location where the halos are compressed, like two balloons pushing against each other.”

A 3-panel graphic labelled “artist’s concept” at bottom, right corner. Each of the three panels shows the same whitish, whirlpool-like spiral galaxy at middle of top edge. A faint, purple haze surrounds galaxy and stretches to panel’s edges. At the middle of the right side of the first panel, a white dot surrounded by fuzzy, lighter purple halo approaches. In middle panel, a pronounced, light purple bow shock develops to left part of the halo. The right part of halo is being stripped and blown back into a streaming tail of gas. The bottom panel shows the tail becoming longer and more defined as the now tadpole-like object curves below the spiral galaxy and sweeps toward the upper left.
This artist’s concept illustrates the Large Magellanic Cloud’s (LMC’s) encounter with the Milky Way galaxy’s gaseous halo. In the top panel, at the middle of the right side, the LMC begins crashing through our galaxy’s much more massive halo. The bright purple bow shock represents the leading edge of the LMC’s halo, which is being compressed as the Milky Way’s halo pushes back against the incoming LMC. In the middle panel, part of the halo is being stripped and blown back into a streaming tail of gas that eventually will rain into the Milky Way. The bottom panel shows the progression of this interaction, as the LMC’s comet-like tail becomes more defined. A compact LMC halo remains. Because the LMC is just past its closest approach to the Milky Way and is moving outward into deep space again, scientists do not expect the residual halo will be lost.
Credit: NASA, ESA, R. Crawford (STScI)

More information

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
Image credit: NASA, ESA, R. Crawford (STScI)

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Press release from ESA Hubble

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Webb and Hubble examine spooky spiral galaxies: IC 2163 and NGC 2207

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Webb and Hubble examine spooky spiral galaxies: IC 2163 and NGC 2207

Stare deeply at these galaxies. They appear as if blood is pumping through the top of a flesh-free face. The long, ghastly ‘stare’ of their searing eye-like cores shines out into the supreme cosmic darkness.

Two spiral galaxies take up almost the entire view and appear to be overlapping. The galaxy at left, IC 2163, is smaller and more compact than the galaxy at right, NGC 2207. The black background of space is dotted with foreground stars and extremely distant galaxies.
The gruesome palette of these galaxies is owed to a mix of mid-infrared light from the NASA/ESA/CSA James Webb Space Telescope, and visible and ultraviolet light from the NASA/ESA Hubble Space Telescope. The pair grazed one another millions of years ago. The smaller spiral on the left, catalogued as IC 2163, passed behind NGC 2207, the larger spiral galaxy at right.
Both have increased star formation rates. Combined, they are estimated to form the equivalent of two dozen new stars that are the size of the Sun annually. Our Milky Way galaxy forms the equivalent of two or three new Sun-like stars per year.
Both galaxies have hosted seven known supernovae, each of which may have cleared space in their arms, rearranging gas and dust that later cooled, and allowed many new stars to form. (Find these areas by looking for the bluest regions).
Credit: NASA, ESA, CSA, STScI

These galaxies have only grazed one another so far, with the smaller spiral on the left, catalogued as IC 2163, ever so slowly ‘creeping’ behind NGC 2207, the spiral galaxy on the right, millions of years ago.

The pair’s macabre colours represent a combination of mid-infrared light from the NASA/ESA/CSA James Webb Space Telescope and visible and ultraviolet light from the NASA/ESA Hubble Space Telescope.

Look for potential evidence of their ‘light scrape’ in the shock fronts, where material from the galaxies may have slammed together. These lines represented in brighter red, including the ‘eyelids’, may cause the appearance of the galaxies’ bulging, vein-like arms.

The galaxies’ first pass may have also distorted their delicately curved arms, pulling out tidal extensions in several places. The diffuse, tiny spiral arms between IC 2163’s core and its far left arm may be an example of this activity. Even more tendrils look like they’re hanging between the galaxies’ cores. Another extension ‘drifts’ off the top of the larger galaxy, forming a thin, semi-transparent arm that practically runs off screen.

Both galaxies have high star formation rates, like innumerable individual hearts fluttering all across their arms. Each year, the galaxies produce the equivalent of two dozen new stars that are the size of the Sun. Our Milky Way galaxy only forms the equivalent of two or three new Sun-like stars per year. Both galaxies have also hosted seven known supernovae in recent decades, a high number compared to an average of one every 50 years in the Milky Way. Each supernova may have cleared space in the galaxies’ arms, rearranging gas and dust that later cooled, and allowed many new stars to form.

To spot the star-forming ‘action sequences,’ look for the bright blue areas captured by Hubble in ultraviolet light, and the pink and white regions detailed mainly by Webb’s mid-infrared data. Larger areas of stars are known as super star clusters. Look for examples of these in the top-most spiral arm that wraps above the larger galaxy and points left. Other bright regions in the galaxies are mini starbursts — locations where many stars form in quick succession. Additionally, the top and bottom ‘eyelid’ of IC 2163, the smaller galaxy on the left, is filled with newer star formation and burns brightly.

A graphic labelled “Hubble and Webb Space Telescopes; Spiral Galaxies IC 2163 and NGC 2207.” At the centre are two overlapping spiral galaxies set against the black background of space.
This image of galaxies IC 2163 and NGC 2207, captured by the Hubble and James Webb space telescopes. Hubble’s data are from its Wide Field Planetary Camera 2 (WFPC2). Webb’s data are from its Mid-InfraRed Instrument (MIRI).
The image shows a scale bar, compass arrows, and colour key for reference.
The scale bar is labelled in light-years along the top, which is the distance that light travels in one Earth-year. (It takes three years for light to travel a distance equal to the length of the scale bar.) One light-year is equal to about 9.46 trillion kilometres.
The scale bar is also labelled in arcminutes, which is a measure of angular distance on the sky. One arcsecond is equal to an angular measurement of 1/3600 of one degree. There are 60 arcminutes in a degree and 60 arcseconds in an arcminute. (The full Moon has an angular diameter of about 30 arcminutes.) The actual size of an object that covers one arcsecond on the sky depends on its distance from the telescope.
The north and east compass arrows show the orientation of the image on the sky. Note that the relationship between north and east on the sky (as seen from below) is flipped relative to direction arrows on a map of the ground (as seen from above).
This image shows invisible ultraviolet, visible, and mid-infrared wavelengths of light that have been translated into visible-light colours. The colour key shows which WFPC2 and MIRI filters were used when collecting the light. The colour of each filter name is the visible-light colour used to represent the infrared light that passes through that filter.
Credit: NASA, ESA, CSA, STScI

What’s next for these spirals? Over many millions of years, the galaxies may swing by one another repeatedly. It’s possible that their cores and arms will meld, leaving behind completely reshaped arms, and an even brighter, cyclops-like ‘eye’ at the core. Star formation will also slow down once their stores of gas and dust deplete, and the scene will calm.

Two spiral galaxies take up almost the entire view and appear to be overlapping. They are angled from top left to bottom right. The galaxy at left, IC 2163, is smaller and more compact than the galaxy at right, NGC 2207. The background of space is black, dotted with tiny foreground stars and extremely distant galaxies.
The James Webb Space Telescope’s mid-infrared image of galaxies IC 2163 and NGC 2207 recalls the iciness of long-dead bones mixed with eerie vapours. Two large luminous ‘eyes’ lie at the galaxies’ cores, and gauzy spiral arms reach out into the vast distances of space.
Webb’s mid-infrared image excels at showing where the cold dust glows throughout these galaxies — and helps pinpoint where stars and star clusters are buried within the dust. Find these regions by looking for the pink dots along the spiral arms. Many of these areas are home to actively forming stars that are still encased in the gas and dust that feeds their growth. Other pink dots may be objects that lie well behind these galaxies, including extremely distant active supermassive black holes known as quasars.
The largest, brightest pink region that glimmers with eight prominent diffraction spikes at the bottom right is a mini starburst — a location where many stars are forming in quick succession. Find the lace-like holes in the spiral arms. These areas are brimming with star formation.
Finally, scan the black background of space, where objects shine brightly in a rainbow of colours. Blue circles with tiny diffraction spikes are foreground stars. Objects without spikes are very distant galaxies.
Credit: NASA, ESA, CSA, STScI

Want to ‘pull apart’ these images? Examine the galaxies’ skeleton-like appearance in Webb’s mid-infrared image, and compare the Hubble and Webb images side by side.

Two views of the same object are shown side by side, split evenly. The Hubble observation is at left, and the Webb observation is at right. Both show an angled pair of spiral galaxies, IC 2163 at top left, and NGC 2207, at bottom right.
These are two views of the same scene, each showing two overlapping spiral galaxies, IC 2163 at left and NGC 2207 at right. The NASA/ESA Hubble Space Telescope’s ultraviolet- and visible-light observation is at left, and the NASA/ESA/CSA James Webb Space Telescope’s mid-infrared light observation is at right.
In Hubble’s image, the star-filled spiral arms glow brightly in blue, and the galaxies’ cores in orange. Both galaxies are covered in dark brown dust lanes, which obscure the view of IC 2163’s core at left.
In Webb’s image, cold dust takes centre stage, casting the galaxies’ arms in white. Areas where stars are still deeply embedded in the dust appear pink. Other pink dots may be objects that lie well behind these galaxies, including active supermassive black holes known as quasars.
Turn your eye toward the bottom right of the Webb image. The largest, brightest pink region that glimmers with eight prominent diffraction spikes is a mini starburst — a location where many stars are forming in quick succession. The same region in the Hubble image appears as a bright blue cluster of stars.
The lace-like holes in the white spiral arms of Webb’s images are often where supernovae exploded long ago. In the same regions, Hubble shows these areas are now populated with newer stars.
The black areas to the upper right and lower left of the Hubble image do not contain any data.
Credit: NASA, ESA, CSA, STScI

 

Press release from ESA Webb.

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Webb finds candidates for first young brown dwarfs outside the Milky Way, in the star cluster NGC 602

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young brown dwarfs outside the Milky Way NGC 602 A star cluster is shown inside a large nebula of many-coloured gas and dust. The material forms dark ridges and peaks of gas and dust surrounding the cluster, lit on the inner side, while layers of diffuse, translucent clouds blanket over them. Around and within the gas, a huge number of distant galaxies can be seen, some quite large, as well as a few stars nearer to us which are very large and bright.

Webb finds candidates for first young brown dwarfs outside the Milky Way, in the star cluster NGC 602

An international team of astronomers has used the NASA/ESA/CSA James Webb Space Telescope to detect the first rich population of brown dwarf candidates outside the Milky Way in the star cluster NGC 602.

Near the outskirts of the Small Magellanic Cloud, a satellite galaxy roughly 200 000 light-years from Earth, lies the young star cluster NGC 602. The local environment of this cluster is a close analogue of what existed in the early Universe, with very low abundances of elements heavier than hydrogen and helium. The existence of dark clouds of dense dust and the fact that the cluster is rich in ionised gas also suggest the presence of ongoing star formation processes. Together with its associated HII [1] region N90, which contains clouds of ionised atomic hydrogen, this cluster provides a valuable opportunity to examine star formation scenarios under dramatically different conditions from those in the solar neighbourhood.

An international team of astronomers, including Peter Zeidler, Elena Sabbi, Elena Manjavacas and Antonella Nota, used Webb to observe NGC 602 and they detected candidates for the first young brown dwarfs outside our Milky Way.

“Only with the incredible sensitivity and spatial resolution in the correct wavelength regime is it possible to detect these objects at such great distances,” shared lead author Peter Zeidler of AURA/STScI for the European Space Agency. “This has never been possible before and also will remain impossible from the ground for the foreseeable future.”

Brown dwarfs are the more massive cousins of giant gas planets (typically ranging from roughly 13 to 75 Jupiter masses, and sometimes lower). They are free-floating, meaning that they are not gravitationally bound to a star as exoplanets are. However, some of them share characteristics with exoplanets, like their atmospheric composition and storm patterns.

“Until now, we’ve known of about 3000 brown dwarfs, but they all live inside our own galaxy,” added team member Elena Manjavacas of AURA/STScI for the European Space Agency.

“This discovery highlights the power of using both Hubble and Webb to study young stellar clusters,” explained team member Antonella Nota, executive director of the International Space Science Institute in Switzerland and the previous Webb Project Scientist for ESA. “Hubble showed that NGC602 harbors very young low mass stars, but only with Webb we can finally see the extent and the significance of the substellar mass formation in this cluster. Hubble and Webb are an amazingly powerful telescope duo!”

“Our results fit very well with the theory that the mass distribution of bodies below the hydrogen burning limit is simply a continuation of the stellar distribution,” shared Zeidler. “It seems they form in the same way, they just don’t accrete enough mass to become a fully fledged star.”

The team’s data include a new image from Webb’s Near-InfraRed Camera (NIRCam) of NGC 602, which highlights the cluster stars, the young stellar objects, and the surrounding gas and dust ridges, as well as the gas and dust itself, while also showing the significant contamination by background galaxies and other stars in the Small Magellanic Cloud. These observations were made in April 2023.

“By studying the young metal-poor brown dwarfs newly discovered in NGC602, we are getting closer to unlocking the secrets of how stars and planets formed in the harsh conditions of the early Universe,“ added team member Elena Sabbi of NSF’s NOIRLab, the University of Arizona, and the Space Telescope Science Institute.

“These are the first substellar objects outside the Milky Way” added Manjavacas. “We need to be ready for new ground-breaking discoveries in these new objects!”

These observations were made as part of the JWST GO programme #2662 (PI: P. Zeidler). The results have been published in The Astrophysical Journal.

A star cluster is shown inside a large nebula of many-coloured gas and dust. The material forms dark ridges and peaks of gas and dust surrounding the cluster, lit on the inner side, while layers of diffuse, translucent clouds blanket over them. Around and within the gas, a huge number of distant galaxies can be seen, some quite large, as well as a few stars nearer to us which are very large and bright.
Near the outskirts of the Small Magellanic Cloud, a satellite galaxy roughly 200 000 light-years from Earth, lies the young star cluster NGC 602, which is featured in this new image from the NASA/ESA/CSA James Webb Space Telescope. This image includes data from Webb’s NIRCam (Near-InfraRed Camera) and MIRI (Mid-InfraRed Instrument).
The local environment of this cluster is a close analogue of what existed in the early Universe, with very low abundances of elements heavier than hydrogen and helium. The existence of dark clouds of dense dust and the fact that the cluster is rich in ionised gas also suggest the presence of ongoing star formation processes. This cluster provides a valuable opportunity to examine star formation scenarios under dramatically different conditions from those in the solar neighbourhood.
An international team of astronomers, including Peter Zeidler, Elena Sabbi, and Antonella Nota, used Webb to observe NGC 602 and detected candidates for the first young brown dwarfs outside our Milky Way.
Credit: ESA/Webb, NASA & CSA, P. Zeidler, E. Sabbi, A. Nota, M. Zamani (ESA/Webb)

Notes

[1] Some of the most beautiful extended objects that we can see are known as HII regions, also called diffuse or emission nebulae. They contain mostly ionised hydrogen and are found throughout the interstellar medium in the Milky Way and in other galaxies.

Press release from ESA Webb.

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Hubble captures intricacies of R Aquarii

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R Aquarii A bright binary star surrounded by a nebula. The star, in the centre, is a large white spot surrounded by a circular glow. It has a large, X-shaped set of diffraction spikes around it. The nebula extends far above, below, left and right of the star in long, arcing shapes made of thin, multicoloured filaments — mostly red and greenish colours, but lit in a bright cyan near the star where its light illuminates the gas.

Hubble captures intricacies of R Aquarii

The NASA/ESA Hubble Space Telescope has provided a dramatic and colourful close-up look at one of the most rambunctious stars in our galaxy, weaving a huge spiral pattern among the stars. Hubble’s images capture its details and its evolution is featured by a unique timelapse video.

Residing only roughly 700 light-years from Earth in the constellation Aquarius, R Aquarii is a symbiotic binary star: a type of binary star system consisting of a white dwarf and a red giant that is surrounded by a large, dynamic nebula. As the closest symbiotic star to Earth, R Aquarii was studied by none other than Edwin Hubble in an effort to understand the mechanism that powers the system.

R Aquarii undergoes violent eruptions that blast out huge filaments of glowing gas. This dramatically demonstrates how the Universe redistributes the products of nuclear energy that form deep inside stars and jet back into space.

R Aquarii belongs to a class of double stars called symbiotic stars. The primary star is an aging red giant and its companion is a compact burned-out star known as a white dwarf. The red giant primary star is classified as a Mira variable that is over 400 times larger than our Sun. The bloated monster star pulsates, changes temperature, and varies in brightness by a factor of 750 times over a roughly 390-day period. At its peak the star is blinding at nearly 5,000 times our Sun’s brightness. When the white dwarf swings closest to the red giant along its 44-year orbital period, it gravitationally siphons off hydrogen gas. This material accumulates in the accretion disk surrounding the white dwarf, until it undergoes a powerful outburst and jet ejection, especially during the closest approach of the white dwarf to the red giant donor star.

These events have more than just a passing interest to astronomers and laymen alike in that this is one known way — as well as the truly titanic but extremely rare supernova events — to release chemical elements heavier than hydrogen and helium into the interstellar medium. Heavier elements like carbon, nitrogen, and oxygen are critical building blocks of planets like the Earth and lifeforms such as our own. They are formed in the deep interiors of stars, where the temperature is high enough to fuse hydrogen and helium.

This outburst ejects powerful jets seen as filaments shooting out from the binary system, forming loops and trails as the plasma emerges in streamers. The plasma is twisted by the force of the explosion and channeled upwards and outwards by strong magnetic fields. The outflow appears to bend back on itself into a spiral pattern. The filaments are glowing in visible light because they are energized by blistering radiation from the stellar duo that is R Aquarii. The nebula around the binary star is known as Cederblad 211, and may be the remnant of a past nova.

The scale of the event is extraordinary even in astronomical terms since emitting material can be traced out to at least 400 billion kilometres — or 2,500 times the distance between the Sun and the Earth — from the central core.

The ESA/Hubble team has developed a unique timelapse of the object consisting of multiple observing programmes that span from 2014 to 2023. Across the five images, the rapid and dramatic evolution of the binary star and its surrounding nebula can be seen. The binary star dims and brightens, seen by the size of the red diffraction spikes around it, due to the strong pulsations of the red giant star. The nebula is shown in mostly green colours, but bluer parts of it come in and out of view: this is because they are being illuminated as the lighthouse-like beam of light from the spinning binary star sweeps over them.

A bright binary star surrounded by a nebula. The star, in the centre, is a large white spot surrounded by a circular glow. It has a large, X-shaped set of diffraction spikes around it. The nebula extends far above, below, left and right of the star in long, arcing shapes made of thin, multicoloured filaments — mostly red and greenish colours, but lit in a bright cyan near the star where its light illuminates the gas.
This image features R Aquarii, a symbiotic binary star that lies only roughly 1,000 light-years from Earth in the constellation Aquarius. This is a type of binary star system consisting of a white dwarf and a red giant that is surrounded by a large, dynamic nebula.
Credit: NASA, ESA, M. Stute, M. Karovska, D. de Martin & M. Zamani (ESA/Hubble)

Press release from ESA Hubble

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Hubble’s observations of Jupiter’s Great Red Spot, collected between December 2023 to March 2024

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Eight Hubble images showing Jupiter’s Great Red Spot. The GRS appears as a bright red oval in the middle of cream-coloured cloud bands. The images trace changes in the GRS’s size, shape, brightness, colour, and twisting, over a period of 90 days between December 2023 and March 2024.

Hubble’s new observations of Jupiter’s Great Red Spot, collected over 90 days between December 2023 to March 2024

Astronomers have observed Jupiter’s legendary Great Red Spot (GRS), an anticyclone large enough to swallow Earth, for at least 150 years. But there are always new surprises – especially when the NASA/ESA Hubble Space Telescope takes a close-up look at it.

Eight Hubble images showing Jupiter’s Great Red Spot. The GRS appears as a bright red oval in the middle of cream-coloured cloud bands. The images trace changes in the GRS’s size, shape, brightness, colour, and twisting, over a period of 90 days between December 2023 and March 2024.
Using Hubble Space Telescope data spanning approximately 90 days (between December 2023 and March 2024) when the giant planet Jupiter was approximately 740 million kilometres from the Sun, astronomers measured the Great Red Spot’s size, shape, brightness, colour, and vorticity over one full oscillation cycle. The data reveal that the Great Red Spot is not as stable as it might look. It was observed going through an oscillation in its elliptical shape, jiggling like a bowl of gelatin. The cause of the 90-day oscillation is unknown.
Credit: NASA, ESA, A. Simon (GSFC)

Hubble’s new observations of the famous red storm, collected over 90 days between December 2023 to March 2024, reveal that the GRS is not as stable as it might look. The recent data show the GRS jiggling like a bowl of gelatin. The combined Hubble images allowed astronomers to assemble a time-lapse movie of the squiggly behaviour of the GRS.

“While we knew its motion varies slightly in its longitude, we didn’t expect to see the size oscillate. As far as we know, it’s not been identified before,” said Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This is really the first time we’ve had the proper imaging cadence of the GRS. With Hubble’s high resolution we can say that the GRS is definitively squeezing in and out at the same time as it moves faster and slower. That was very unexpected, and at present there are no hydrodynamic explanations.”

Hubble monitors Jupiter and the other outer solar system planets every year through the Outer Planet Atmospheres Legacy program (OPAL) led by Simon, but these observations were from a program dedicated to the GRS. Understanding the mechanisms of the largest storms in the solar system puts the theory of hurricanes on Earth into a broader cosmic context, which might be applied to better understanding the meteorology on planets around other stars.

Eight images of the giant planet Jupiter spanning approximately 90 days between December 2023 and March 2024. The planet appears striped, with brown and white horizontal bands of clouds. These stripes are called belts (sinking air) and bands (rising air). The polar regions appear more mottled.
Using Hubble Space Telescope data spanning approximately 90 days (between December 2023 and March 2024) when the giant planet Jupiter was approximately 740 million kilometres from the Sun, astronomers measured the Great Red Spot’s size, shape, brightness, colour, and vorticity over a full oscillation cycle. The data reveal that the Great Red Spot is not as stable as it might look. It was observed going through an oscillation in its elliptical shape, jiggling like a bowl of gelatin. The cause of the 90-day oscillation is unknown. The observation is part of the Outer Planet Atmospheres Legacy program (OPAL).
Credit: NASA, ESA, A. Simon (GSFC)

Simon’s team used Hubble to zoom in on the GRS for a detailed look at its size, shape, and any subtle colour changes.

“When we look closely, we see a lot of things are changing from day to day,” said Simon.

This includes ultraviolet-light observations showing that the distinct core of the storm gets brightest when the GRS is at its largest size in its oscillation cycle. This indicates less haze absorption in the upper atmosphere.

“As it accelerates and decelerates, the GRS is pushing against the windy jet streams to the north and south of it,” said co-investigator Mike Wong of the University of California at Berkeley. “It’s similar to a sandwich where the slices of bread are forced to bulge out when there’s too much filling in the middle.” 

Wong contrasted this to Neptune, where dark spots can drift wildly in latitude without strong jet streams to hold them in place. Jupiter’s Great Red Spot has been held at a southern latitude, trapped between the jet streams, for the extent of Earth-bound telescopic observations.

The team has continued watching the GRS shrink since the OPAL program began 10 years ago. They predict it will keep shrinking before taking on a stable, less-elongated, shape. 

“Right now it’s over-filling its latitude band relative to the wind field. Once it shrinks inside that band the winds will really be holding it in place,” said Simon.

The team predicts that the GRS will probably stabilise in size, but for now Hubble only observed it for one oscillation cycle.

“This is a great example of the power of Hubble’s exquisite imaging for monitoring of the atmospheres of the outer planets,” said co-investigator Patrick Irwin of the University of Oxford. “With these new observations we were able to study the dynamics and evolution of the GRS over three months, building on our understanding of the long-term properties of Jupiter obtained from the OPAL program over the past decade.”

The researchers hope that in the future other high-resolution images from Hubble might identify other Jovian parameters that indicate the underlying cause of the oscillation.

 

Press release from ESA Hubble

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Bottlenose dolphins “smile” at each other while playing

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bottlenose dolphins smile when playing I delfini si "sorridono" a vicenda durante il gioco

Bottlenose dolphins “smile” at each other while playing

Dolphins are extremely playful, but little is known about how they—and other marine mammals—communicate during playtime. New research publishing October 2 in the Cell Press journal iScience shows that bottlenose dolphins (Tursiops truncates) use the “open mouth” facial expression—analogous to a smile—to communicate during social play. The dolphins almost always use the facial expression when they are in their playmate’s field of view, and when playmates perceived a “smile,” they responded in kind 33% of the time.

“We’ve uncovered the presence of a distinct facial display, the open mouth, in bottlenose dolphins, and we showed that dolphins are also able to mirror others’ facial expression,” says senior author and evolutionary biologist Elisabetta Palagi (@bettapalagi) of the University of Pisa. “Open-mouth signals and rapid mimicry appear repeatedly across the mammal family tree, which suggests that visual communication has played a crucial role in shaping complex social interactions, not only in dolphins but in many species over time.”

Dolphin play can include acrobatics, surfing, playing with objects, chasing, and playfighting, and it’s important that these activities aren’t misinterpreted as aggression. Other mammals use facial expressions to communicate playfulness, but whether marine mammals also use facial expressions to signal playtime hasn’t been previously explored.

“The open mouth gesture likely evolved from the biting action, breaking down the biting sequence to leave only the ‘intention to bite’ without contact,” says Palagi. “The relaxed open mouth, seen in social carnivores, monkeys’ play faces, and even human laughter, is a universal sign of playfulness, helping animals—and us—signal fun and avoid conflict.”

To investigate whether dolphins visually communicate playfulness, the researchers recorded captive bottlenose dolphins while they were playing in pairs and while they were playing freely with their human trainers.

They showed that dolphins frequently use the open mouth expression when playing with other dolphins, but they don’t seem to use it when playing with humans or when they’re playing by themselves. While only one open mouth event was recorded during solitary play, the researchers recorded a total of 1,288 open mouth events during social play sessions, and 92% of these events occurred during dolphin–dolphin play sessions. Dolphins were also more likely to assume the open mouth expression when their faces were in the field of view of their playmate—89% of recorded open mouth expressions were emitted in this context—and when this “smile” was perceived, the playmate smiled back 33% of the time.

“Some may argue that dolphins are merely mimicking each other’s open mouth expressions by chance, given they’re often involved in the same activity or context, but this doesn’t explain why the probability of mimicking another dolphin’s open mouth within 1 second is 13 times higher when the receiver actually sees the original expression,” says Palagi. “This rate of mimicry in dolphins is consistent with what’s been observed in certain carnivores, such as meerkats and sun bears.”

The researchers didn’t record the dolphins’ acoustic signals during playtime, and they say that future studies should investigate the possible role of vocalizations and tactile signals during playful interactions.

“Future research should dive into eye-tracking to explore how dolphins see their world and utilize acoustic signals in their multimodal communication during play,” says corresponding author and zoologist Livio Favaro (@LivioF_80). “Dolphins have developed one of the most intricate vocal systems in the animal world, but sound can also expose them to predators or eavesdroppers. When dolphins play together, a mix of whistling and visual cues helps them cooperate and achieve goals, a strategy particularly useful during social play when they’re less on guard for predators.”

Bibliographic information:
Maglieri et al., “Smiling underwater: exploring playful signals and rapid mimicry in bottlenose dolphins”, iScience, DOI: http://dx.doi.org/10.1016/j.isci.2024.110966
Press release from Cell Press.
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Barnard b, a planet orbiting the closest single star to our Sun

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This artist’s impression shows Barnard b, a sub-Earth-mass planet that was discovered orbiting Barnard’s star. Its signal was detected with the ESPRESSO instrument on ESO’s Very Large Telescope (VLT), and astronomers were able to confirm it with data from other instruments. An earlier promising detection in 2018 around the same star could not be confirmed by these data. On this newly discovered exoplanet, which has at least half the mass of Venus but is too hot to support liquid water, a year lasts just over three Earth days. Crediti: ESO/M. Kornmesser

Scientists discover Barnard b, a planet orbiting the closest single star to our Sun

This artist’s impression shows Barnard b, a sub-Earth-mass planet that was discovered orbiting Barnard’s star. Its signal was detected with the ESPRESSO instrument on ESO’s Very Large Telescope (VLT), and astronomers were able to confirm it with data from other instruments. An earlier promising detection in 2018 around the same star could not be confirmed by these data. On this newly discovered exoplanet, which has at least half the mass of Venus but is too hot to support liquid water, a year lasts just over three Earth days.Crediti: ESO/M. Kornmesser
This artist’s impression shows Barnard b, a sub-Earth-mass planet that was discovered orbiting Barnard’s star. Its signal was detected with the ESPRESSO instrument on ESO’s Very Large Telescope (VLT), and astronomers were able to confirm it with data from other instruments. An earlier promising detection in 2018 around the same star could not be confirmed by these data. On this newly discovered exoplanet, which has at least half the mass of Venus but is too hot to support liquid water, a year lasts just over three Earth days. Credits: ESO/M. Kornmesser

Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have discovered an exoplanet orbiting Barnard’s star, the closest single star to our Sun. On this newly discovered exoplanet, which has at least half the mass of Venus, a year lasts just over three Earth days. The team’s observations also hint at the existence of three more exoplanet candidates, in various orbits around the star.

Located just six light-years away, Barnard’s star is the second-closest stellar system — after Alpha Centauri’s three-star group — and the closest individual star to us. Owing to its proximity, it is a primary target in the search for Earth-like exoplanets. Despite a promising detection back in 2018, no planet orbiting Barnard’s star had been confirmed until now.

Graphic representation of the relative distances between the nearest stars and the Sun. Barnard’s star is the second closest star system to the Sun, and the nearest single star to us.
Credits: IEEC/Science-Wave – Guillem Ramisa
Il grafico mostra la costellazione di Ofiuco (o Serpentario), a cavallo dell'equatore celeste. È indicata la posizione della stella di Barnard, così come l'ubicazione della maggior parte delle stelle visibili a occhio nudo in una notte buia e serena. Crediti: ESO, IAU and Sky & Telescope
This chart shows the constellation of Ophiuchus (the Serpent-Bearer), which straddles the celestial equator. The chart shows the location of Barnard’s Star and marks most of the stars visible to the unaided eye on a clear dark night… Credits: ESO, IAU and Sky & Telescope

The discovery of this new exoplanet — announced in a paper published today in the journal Astronomy & Astrophysics — is the result of observations made over the last five years with ESO’s VLT, located at Paranal Observatory in Chile.

“Even if it took a long time, we were always confident that we could find something,”

says Jonay González Hernández, a researcher at the Instituto de Astrofísica de Canarias in Spain, and lead author of the paper. The team were looking for signals from possible exoplanets within the habitable or temperate zone of Barnard’s star — the range where liquid water can exist on the planet’s surface. Red dwarfs like Barnard’s star are often targeted by astronomers since low-mass rocky planets are easier to detect there than around larger Sun-like stars. [1]

Barnard b [2], as the newly discovered exoplanet is called, is twenty times closer to Barnard’s star than Mercury is to the Sun. It orbits its star in 3.15 Earth days and has a surface temperature around 125 °C.

“Barnard b is one of the lowest-mass exoplanets known and one of the few known with a mass less than that of Earth. But the planet is too close to the host star, closer than the habitable zone,” explains González Hernández. “Even if the star is about 2500 degrees cooler than our Sun, it is too hot there to maintain liquid water on the surface.”

For their observations, the team used ESPRESSO, a highly precise instrument designed to measure the wobble of a star caused by the gravitational pull of one or more orbiting planets. The results obtained from these observations were confirmed by data from other instruments also specialised in exoplanet hunting: HARPS at ESO’s La Silla Observatory, HARPS-N and CARMENES. The new data do not, however, support the existence of the exoplanet reported in 2018.

In addition to the confirmed planet, the international team also found hints of three more exoplanet candidates orbiting the same star. These candidates, however, will require additional observations with ESPRESSO to be confirmed.

“We now need to continue observing this star to confirm the other candidate signals,” says Alejandro Suárez Mascareño, a researcher also at the Instituto de Astrofísica de Canarias and co-author of the study. “But the discovery of this planet, along with other previous discoveries such as Proxima b and d, shows that our cosmic backyard is full of low-mass planets.”

ESO’s Extremely Large Telescope (ELT), currently under construction, is set to transform the field of exoplanet research. The ELT’s ANDES instrument will allow researchers to detect more of these small, rocky planets in the temperate zone around nearby stars, beyond the reach of current telescopes, and enable them to study the composition of their atmospheres.

La panoramica mostra i dintorni della nana rossa nota come stella di Barnard, nella costellazione dell'Ofiuco. L'immagine è stata prodotta a partire dai dati della DSS2 (Digitized Sky Survey 2). Nel centro dell'immagine si trova la stella di Barnard, catturata in tre diverse esposizioni. La stella è la più veloce nel cielo notturno e il suo grande moto proprio - lo spostamento apparente sulla volta celeste - viene evidenziato dal fatto che la posizione cambi tra osservazioni successive - mostrate in rosso, giallo e blu. Crediti: ESO/Digitized Sky Survey 2 Acknowledgement: Davide De Martin E — Red Dots
This wide-field image shows the surroundings of the red dwarf known as Barnard’s Star in the constellation of Ophiuchus (the Serpent-Bearer). This picture was created from material forming part of the Digitized Sky Survey 2. The centre of the image shows Barnard’s Star captured in three different exposures. The star is the fastest moving star in the night sky and its large apparent motion can be seen as its position changes between successive observations — shown in red, yellow and blue..
Credits: ESO/Digitized Sky Survey 2 Acknowledgement: Davide De Martin
E — Red Dots

Notes

[1] Astronomers target cool stars, like red dwarfs, because their temperate zone is much closer to the star than that of hotter stars, like the Sun. This means that the planets orbiting within their temperate zone have shorter orbital periods, allowing astronomers to monitor them over several days or weeks, rather than years. In addition, red dwarfs are much less massive than the Sun, so they are more easily disturbed by the gravitational pull of the planets around them and thus they wobble more strongly.
[2] It’s common practice in science to name exoplanets by the name of their host star with a lowercase letter added to it, ‘b’ indicating the first known planet, ’c’ the next one, and so on. The name Barnard b was therefore also given to a previously suspected planet candidate around Barnard’s star, which scientists were unable to confirm.

More information

This research was presented in the paper “A sub-Earth-mass planet orbiting Barnard’s star” to appear in Astronomy & Astrophysics. (https://www.aanda.org/10.1051/0004-6361/202451311)

The team is composed of J. I. González Hernández (Instituto de Astrofísica de Canarias, Spain [IAC] and Departamento de Astrofísica, Universidad de La Laguna, Spain [IAC-ULL]), A. Suárez Mascareño (IAC and IAC-ULL), A. M. Silva (Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, Portugal [IA-CAUP] and Departamento de Física e Astronomia Faculdade de Ciências, Universidade do Porto, Portugal [FCUP]), A. K. Stefanov (IAC and IAC-ULL), J. P. Faria (Observatoire de Genève, Université de Genève, Switzerland [UNIGE]; IA-CAUP and FCUP), H. M. Tabernero (Departamento de Física de la Tierra y Astrofísica & Instituto de Física de Partículas y del Cosmos, Universidad Complutense de Madrid, Spain), A. Sozzetti (INAF – Osservatorio Astrofisico di Torino [INAF-OATo] and Istituto Nazionale di Astrofisica, Torino, Italy), R. Rebolo (IAC; IAC-ULL and Consejo Superior de Investigaciones Científicas, Spain [CSIC]), F. Pepe (UNIGE), N. C. Santos (IA-CAUP; FCUP), S. Cristiani (INAF – Osservatorio Astronomico di Trieste, Italy [INAF-OAT] and Institute for Fundamental Physics of the Universe, Trieste, Italy [IFPU]), C. Lovis (UNIGE), X. Dumusque (UNIGE), P. Figueira (UNIGE and IA-CAUP), J. Lillo-Box (Centro de Astrobiología, CSIC-INTA, Madrid, Spain [CAB]), N. Nari (IAC; Light Bridges S. L., Canarias, Spain and IAC-ULL), S. Benatti (INAF – Osservatorio Astronomico di Palermo, Italy [INAF-OAPa]), M. J. Hobson (UNIGE), A. Castro-González (CAB), R. Allart (Institut Trottier de Recherche sur les Exoplanètes, Université de Montréal, Canada and UNIGE), V. M. Passegger (National Astronomical Observatory of Japan, Hilo, USA; IAC; IAC-ULL and Hamburger Sternwarte, Hamburg, Germany), M.-R. Zapatero Osorio (CAB), V. Adibekyan (IA-CAUP and FCUP), Y. Alibert (Center for Space and Habitability, University of Bern, Switzerland and Weltraumforschung und Planetologie, Physikalisches Institut, University of Bern, Switzerland), C. Allende Prieto (IAC and IAC-ULL), F. Bouchy (UNIGE), M. Damasso (INAF-OATo), V. D’Odorico (INAF-OAT and IFPU), P. Di Marcantonio (INAF-OAT), D. Ehrenreich (UNIGE), G. Lo Curto (European Southern Observatory, Santiago, Chile [ESO Chile]), R. Génova Santos (IAC and IAC-ULL), C. J. A. P. Martins (IA-CAUP and Centro de Astrofísica da Universidade do Porto, Portugal), A. Mehner (ESO Chile), G. Micela (INAF-OAPa), P. Molaro (INAF-OAT), N. Nunes (Instituto de Astrofísica e Ciências do Espaço, Universidade de Lisboa), E. Palle (IAC and IAC-ULL), S. G. Sousa (IA-CAUP and FCUP), and S. Udry (UNIGE).

The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czechia, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.

Press release from European Southern Observatory – ESO

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Astronomy

A black hole beam at the core of galaxy M87 seems to cause stars to erupt along its trajectory

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A Hubble photo of galaxy M87, which resembles a translucent, fuzzy white cotton ball. The brightness decreases gradually out in all directions from a bright white point of light at the centre. A wavy blue-white jet of material extends from the point-like core outward to the upper right, about halfway across the galaxy. Stars speckle the background.

Hubble finds that a black hole beam at the core of galaxy M87 seems to cause stars to erupt along its trajectory

In a surprise finding, astronomers using the NASA/ESA Hubble Space Telescope have discovered that the blowtorch-like jet from a supermassive black hole at the core of huge galaxy M87 seems to cause stars to erupt along its trajectory. The stars, called novae, are not caught inside the jet, but are apparently in a dangerous neighbourhood nearby.

An artist’s concept looks down into the core of the galaxy M87, which is just left of centre and appears as a large blue dot. A bright blue-white, narrow and linear jet of plasma transects the illustration from centre left to upper right. It begins at the source of the jet, the galaxy’s black hole, which is surrounded by a blue spiral of material. At lower right is a red giant star that is far from the black hole and close to the viewer. A bridge of glowing gas links the star to a smaller white dwarf star companion immediately to its left. Engorged with infalling hydrogen from the red giant star, the smaller star exploded in a blue-white flash, which looks like numerous diffraction spikes emitted in all directions. Thousands of stars are in the background.
This is an artist’s concept looking down into the core of the giant elliptical galaxy M87. A supermassive black hole ejects a 3,000-light-year-long jet of plasma, travelling at nearly the speed of light. In the foreground, to the right is a binary star system. The system is far from the black hole, but in the vicinity of the jet. In the system, an ageing, swelled-up, normal star spills hydrogen onto a burned-out white dwarf companion star. As the hydrogen accumulates on the surface of the dwarf, it reaches a tipping point where it explodes like a hydrogen bomb. Novae frequently pop-off throughout the giant galaxy of 1 trillion stars, but those near the jet seem to explode more frequently. So far, it’s anybody’s guess why black hole jets enhance the rate of nova eruptions.
Credit: NASA, ESA, J. Olmsted (STScI)

The finding confounds researchers searching for an explanation.

“We don’t know what’s going on, but it’s just a very exciting finding,” said lead author Alec Lessing of Stanford University. “This means there’s something missing from our understanding of how black hole jets interact with their surroundings.”

A nova erupts in a double-star system where an ageing, swelled-up, normal star spills hydrogen onto a burned-out white dwarf companion star. When the dwarf has tanked up a mile-deep surface layer of hydrogen that layer explodes like a giant nuclear bomb. The white dwarf isn’t destroyed by the nova eruption, which ejects its surface layer and then goes back to syphoning fuel from its companion, and the nova-outburst cycle starts over again.

Hubble found twice as many novae going off near the jet as elsewhere in the giant galaxy during the surveyed time period. The jet is launched by a 6.5-billion-solar-mass central black hole surrounded by a disc of swirling matter. The black hole, engorged with infalling matter, launches a 3000-light-year-long jet of plasma blazing through space at nearly the speed of light. Anything caught in the energetic beam would be sizzled. But being near its blistering outflow is apparently also risky, according to the new Hubble findings.

The finding of twice as many novae near the jet implies that there are twice as many nova-forming double-star systems near the jet or that these systems erupt twice as often as similar systems elsewhere in the galaxy.

“There’s something that the jet is doing to the star systems that wander into the surrounding neighbourhood. Maybe the jet somehow snowplows hydrogen fuel onto the white dwarfs, causing them to erupt more frequently,” said Lessing. “But it’s not clear that it’s a physical pushing. It could be the effect of the pressure of the light emanating from the jet. When you deliver hydrogen faster, you get eruptions faster. Something might be doubling the mass transfer rate onto the white dwarfs near the jet.”

Another idea the researchers considered is that the jet is heating the dwarf’s companion star, causing it to overflow further and dump more hydrogen onto the dwarf. However, the researchers calculated that this heating is not nearly large enough to have this effect.

“We’re not the first people who’ve said that it looks like there’s more activity going on around the M87 jet,” said co-investigator Michael Shara of the American Museum of Natural History in New York City. “But Hubble has shown this enhanced activity with far more examples and statistical significance than we ever had before.”

Shortly after Hubble’s launch in 1990, astronomers used its first-generation Faint Object Camera (FOC) to peer into the center of M87 where the monster black hole lurks. They noted that unusual things were happening around the black hole. Almost every time Hubble looked, astronomers saw bluish “transient events” that could be evidence for novae popping off like camera flashes from nearby paparazzi. But the FOC’s view was so narrow that Hubble astronomers couldn’t look away from the jet to compare with the near-jet region. For over two decades, the results remained mysteriously tantalising.

A Hubble photo of galaxy M87, which resembles a translucent, fuzzy white cotton ball. The brightness decreases gradually out in all directions from a bright white point of light at the centre. A wavy blue-white jet of material extends from the point-like core outward to the upper right, about halfway across the galaxy. Stars speckle the background.
A Hubble Space Telescope image of the giant galaxy M87 shows a 3,000-light-year-long jet of plasma blasting from the galaxy’s 6.5-billion-solar-mass central black hole. The blowtorch-like jet seems to cause stars to erupt along its trajectory. These novae are not caught inside the jet, but are apparently in a dangerous neighbourhood nearby. During a recent 9-month survey, astronomers using Hubble found twice as many of these novae going off near the jet as elsewhere in the galaxy. The galaxy is the home of several trillion stars and thousands of star-like globular star clusters.
Credit: NASA, ESA, A. Lessing (Stanford University), E. Baltz (Stanford University), M. Shara (AMNH), J. DePasquale (STScI)

Compelling evidence for the jet’s influence on the stars of the host galaxy was collected over a nine-month interval when Hubble observed with newer, wider-view cameras to count the erupting novae. This was a challenge for the telescope’s observing schedule because it required revisiting M87 precisely every five days for another snapshot. Adding up all of the M87 images led to the deepest images of M87 that have ever been taken.

Hubble found 94 novae in the one-third of M87 that its camera can encompass. “The jet was not the only thing that we were looking at — we were looking at the entire inner galaxy. Once you plotted all known novae on top of M87 you didn’t need statistics to convince yourself that there is an excess of novae along the jet. This is not rocket science. We made the discovery simply by looking at the images. And while we were really surprised, our statistical analyses of the data confirmed what we clearly saw,” said Shara.

“We are witnessing an intriguing but puzzling phenomenon,” commented Chiara Circosta, an ESA Research Fellow, who studies the impact that accreting supermassive blackholes have on the galaxies hosting them in the distant Universe. “I was very surprised by this discovery. Such detailed observations of nearby galaxies are precious to expand our understanding of how jets interact with their host galaxies and potentially affect star formation”

This accomplishment is entirely due to Hubble’s unique capabilities. Ground-based telescope images do not have the clarity to see novae deep inside M87. They cannot resolve stars or stellar eruptions close to the galaxy’s core because the black hole’s surroundings are far too bright. Only Hubble can detect novae against the bright M87 background.

Novae are remarkably common in the Universe. One nova erupts somewhere in M87 every day. But since there are at least 100 billion galaxies throughout the visible universe, around one million novae erupt every second somewhere out there.

 

Press release from ESA Hubble.

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