Six billion tonnes a second: rogue planet Cha 1107-7626 found growing at record rate
Astronomers have identified an enormous ‘growth spurt’ in a so-called rogue planet. Unlike the planets in our Solar System, these objects do not orbit stars, free-floating on their own instead. The new observations, made with the European Southern Observatory’s Very Large Telescope (ESO’s VLT), reveal that this free-floating planet is eating up gas and dust from its surroundings at a rate of six billion tonnes a second. This is the strongest growth rate ever recorded for a rogue planet, or a planet of any kind, providing valuable insights into how they form and grow.
This artist’s impression shows Cha 1107-7626. Located about 620 light-years away, this rogue planet is about 5-10 times more massive than Jupiter and doesn’t orbit a star. It is eating up material from a disc around it and, using ESO’s Very Large Telescope (VLT), astronomers have discovered that it is now doing so at a rate of six billion tonnes per second –– the fastest ever found for any kind of planet. The team suspects that strong magnetic fields could be funnelling material towards the planet, something only seen in stars. When the infalling material reaches the planet it heats up its surface, creating a bright hot spot. The X-shooter spectrograph on ESO’s VLT detected a marked brightening in mid-2025, and found a clear fingerprint that this was caused by infalling gas. The observations show that the planet is now accreting matter about 8 times faster than a few months before. Credit: ESO/L. Calçada/M. Kornmesser
“People may think of planets as quiet and stable worlds, but with this discovery we see that planetary-mass objects freely floating in space can be exciting places,”
says Víctor Almendros-Abad, an astronomer at the Astronomical Observatory of Palermo, National Institute for Astrophysics (INAF), Italy and lead author of the new study.
The newly studied object, which has a mass five to 10 times the mass of Jupiter, is located about 620 light-years away in the constellation Chamaeleon. Officially named Cha 1107-7626, this rogue planet is still forming and is fed by a surrounding disc of gas and dust. This material constantly falls onto the free-floating planet, a process known as accretion. However, the team led by Almendros-Abad has now found that the rate at which the young planet is accreting is not steady.
This infrared image, taken with ESO’s Visible and Infrared Telescope for Astronomy (VISTA) shows the position in the sky of the rogue planet Cha 1107-7626. The planet is a dot located exactly at the centre of the frame. Credit: ESO/Meingast et al.
By August 2025, the planet was accreting about eight times faster than just a few months before, at a rate of six billion tonnes per second!
“This is the strongest accretion episode ever recorded for a planetary-mass object,”
says Almendros-Abad. The discovery, published today in The Astrophysical Journal Letters, was made with the X-shooter spectrograph on ESO’s VLT, located in Chile’s Atacama Desert. The team also used data from the James Webb Space Telescope, operated by the US, European and Canadian space agencies, and archival data from the SINFONI spectrograph on ESO’s VLT.
“The origin of rogue planets remains an open question: are they the lowest-mass objects formed like stars, or giant planets ejected from their birth systems?”
asks co-author Aleks Scholz, an astronomer at the University of St Andrews, United Kingdom. The findings indicate that at least some rogue planets may share a similar formation path to stars since similar bursts of accretion have been spotted in young stars before. As co-author Belinda Damian, also an astronomer at the University of St Andrews, explains:
“This discovery blurs the line between stars and planets and gives us a sneak peek into the earliest formation periods of rogue planets.”
By comparing the light emitted before and during the burst, astronomers gathered clues about the nature of the accretion process. Remarkably, magnetic activity appears to have played a role in driving the dramatic infall of mass, something that has only been observed in stars before. This suggests that even low-mass objects can possess strong magnetic fields capable of powering such accretion events. The team also found that the chemistry of the disc around the planet changed during the accretion episode, with water vapour being detected during it but not before. This phenomenon had been spotted in stars but never in a planet of any kind.
This visible-light image, part of the Digitized Sky Survey 2, shows the position in the sky of the rogue planet Cha 1107-7626. The planet (not visible here) is located exactly at the centre of the frame. Credit: ESO/ Digitized Sky Survey 2
Free-floating planets are difficult to detect, as they are very faint, but ESO’s upcoming Extremely Large Telescope (ELT), operating under the world’s darkest skies for astronomy, could change that. Its powerful instruments and giant main mirror will enable astronomers to uncover and study more of these lonely planets, helping them to better understand how star-like they are. As co-author and ESO astronomer Amelia Bayo puts it:
“The idea that a planetary object can behave like a star is awe-inspiring and invites us to wonder what worlds beyond our own could be like during their nascent stages.”
More information
This research was presented in a paper titled “Discovery of an Accretion Burst in a Free-Floating Planetary-Mass Object” to appear in The Astrophysical Journal Letters (doi:10.3847/2041-8213/ae09a8).
The team is composed of V. Almendros-Abad (Istituto Nazionale di Astrofisica – Osservatorio Astronomico di Palermo, Italy), Aleks Scholz (School of Physics & Astronomy, University of St Andrews, United Kingdom [St Andrews]), Belinda Damian (St Andrews), Ray Jayawardhana (Department of Physics & Astronomy, Johns Hopkins University, USA [JHU]), Amelia Bayo (European Southern Observatory, Germany), Laura Flagg (JHU), Koraljka Mužić (Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências, Universidade de Lisboa, Portugal), Antonella Natta (School of Cosmic Physics, Dublin Institute for Advanced Studies and University College Dublin, Ireland) Paola Pinilla (Mullard Space Science Laboratory, University College London, UK) and Leonardo Testi (Dipartimento di Fisica e Astronomia, Università di Bologna, Italy).
Astronomers witness still-forming planet sculpting the dust around it, near the star HD 135344B
The image to the left, taken with ESO’s Very Large Telescope (VLT), shows a possible planet being born around the young star HD 135344B. This star, located around 440 light-years away, is surrounded by a disc of dust and gas with prominent spiral arms. Theory predicts that planets can sculpt spiral arms like these, and the new planet candidate is located at the base of one of the arms, just as expected. The image was captured with a new VLT instrument: the Enhanced Resolution Imager and Spectrograph (ERIS). The central black circle corresponds to a coronagraph –– a device that blocks the light of the star to reveal faint details around it. The white circle indicates the location of the planet. The image to the right is a combination of previous observations taken with the SPHERE instrument also at the VLT (red) and the Atacama Large Millimeter/submillimeter Array (ALMA, orange and blue). These and other previous studies of HD 135344B did not find signatures of a companion, but ERIS may have finally unveiled the culprit responsible for the star’s spiral disc. Credit: ESO/F. Maio et al./T. Stolker et al./ ALMA (ESO/NAOJ/NRAO)/N. van der Marel et al.
Astronomers may have caught a still-forming planet in action, carving out an intricate pattern in the gas and dust that surrounds its young host star. Using ESO’s Very Large Telescope (VLT), they observed a planetary disc with prominent spiral arms, finding clear signs of a planet nestled in its inner regions. This is the first time astronomers have detected a planet candidate embedded inside a disc spiral.
“We will never witness the formation of Earth, but here, around a young star 440 light-years away, we may be watching a planet come into existence in real time,” says Francesco Maio, a doctoral researcher at the University of Florence, Italy, and lead author of this study, published today in Astronomy & Astrophysics.
The potential planet-in-the-making was detected around the star HD 135344B, within a disc of gas and dust around it called a protoplanetary disc. The budding planet is estimated to be twice the size of Jupiter and as far from its host star as Neptune is from the Sun. It has been observed shaping its surroundings within the protoplanetary disc as it grows into a fully formed planet.
This image, taken with ESO’s Very Large Telescope (VLT), shows a spiral disc around the young star HD 135344B. The image was obtained with the VLT’s Enhanced Resolution Imager and Spectrograph (ERIS) instrument, which found a candidate planet that may be sculpting the spiral features in the disc. The location of this planet is indicated with a white circle. The central black circle corresponds to a coronagraph — a device that blocks the light of the star to reveal faint details around it. Credit: ESO/F. Maio et al.
Protoplanetary discs have been observed around other young stars, and they often display intricate patterns, such as rings, gaps or spirals. Astronomers have long predicted that these structures are caused by baby planets, which sweep up material as they orbit around their parent star. But, until now, they had not caught one of these planetary sculptors in the act.
This image, captured with ESO’s Very Large Telescope (VLT), shows a spiral disc around the young star HD 135344B. The image, which was released in 2016, was obtained with the Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument.
Spiral features like these can be sculpted by planets, although this image doesn’t show evidence of companions orbiting HD 135344B. However, new observations at somewhat longer wavelengths, obtained with the Enhanced Resolution Imager and Spectrograph (ERIS) at the VLT, have found a possible young planet around this star.
The central black circle corresponds to a coronagraph –– a device that blocks the light of the star to reveal faint details around it.
Credit: ESO/T. Stolker et al.
This image, taken with the Atacama Large Millimeter/submillimeter Array (ALMA), and first released in 2015, shows a planet-forming disc around the young star HD 135344B. The image combines a view of both the gas (blue) and the dust (orange) around the star. The star itself is invisible at these wavelengths, and is located in the central gap of the disc.
Credit: ALMA (ESO/NAOJ/NRAO)/N. van der Marel et al.
This image shows the dusty disc around the young star HD 135344B. It’s a combination of data taken with two different facilities: the Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument at ESO’s VLT in red, and the Atacama Large Millimeter/submillimeter Array (ALMA) in orange and blue. The original SPHERE and ALMA images were released in 2016 and 2015 respectively and didn’t show evidence for the presence of a planet in this disc, first revealed in 2025.
Credit: ESO/T. Stolker et al./ALMA (ESO/NAOJ/NRAO)/N. van der Marel et al.
This image from the Digitized Sky Survey (DSS) shows the region of the sky around the star HD 135344B. Right at the centre of the image there are two bright stars close to each other; HD 135344B is the one at the bottom.
Credit: ESO/Digitized Sky Survey 2. Acknowledgement: D. De Martin
This image shows a possible companion orbiting the young star V960 Mon. The star, located more than 5000 light-years away, is surrounded by a disc with intricate features. Previous analysis of the disc showed that it contains clumps of unstable material that could collapse to form a companion object. The new candidate found here could be either a planet or a brown dwarf –– an object bigger than a planet that didn’t gain enough mass to shine as a star.
The candidate object was found with ESO’s Very Large Telescope (VLT), using its new Enhanced Resolution Imager and Spectrograph (ERIS). The new ERIS data are shown here in orange, overlaid on older images of the dusty disc as seen with the VLT’s SPHERE instrument (yellow) and the Atacama Large Millimeter/submillimeter Array (ALMA, in blue).
Credit: ESO/A. Dasgupta/ALMA (ESO/NAOJ/NRAO)/Weber et al.
This image, taken with ESO’s Very Large Telescope (VLT), shows a possible companion orbiting the young star V960 Mon. The image was captured with the VLT’s Enhanced Resolution Imager and Spectrograph (ERIS) instrument. The properties of the object are unknown: it could be a planet or a brown dwarf –– an object bigger than a planet that didn’t gain enough mass to shine as a star.
Credit: ESO/A. Dasgupta
In the case of HD 135344B’s disc, swirling spiral arms had previously been detected by another team of astronomers using SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch), an instrument on ESO’s VLT. However, none of the previous observations of this system found proof of a planet forming within the disc.
Now, with observations from the new VLT’s Enhanced Resolution Imager and Spectrograph (ERIS) instrument, the researchers say they may have found their prime suspect. The team spotted the planet candidate right at the base of one of the disc’s spiral arms, exactly where theory had predicted they might find the planet responsible for carving such a pattern.
“What makes this detection potentially a turning point is that, unlike many previous observations, we are able to directly detect the signal of the protoplanet, which is still highly embedded in the disc,” says Maio, who is based at the Arcetri Astrophysical Observatory, a centre of Italy’s National Institute for Astrophysics (INAF). “This gives us a much higher level of confidence in the planet’s existence, as we’re observing the planet’s own light.”
A star’s companion is born
A different team of astronomers have also recently used the ERIS instrument to observe another star, V960 Mon, one that is still in the very early stages of its life. In a study published on 18 July in The Astrophysical Journal Letters, the team report that they have found a companion object to this young star. The exact nature of this object remains a mystery.
This image shows a possible companion orbiting the young star V960 Mon. The star, located more than 5000 light-years away, is surrounded by a disc with intricate features. Previous analysis of the disc showed that it contains clumps of unstable material that could collapse to form a companion object. The new candidate found here could be either a planet or a brown dwarf –– an object bigger than a planet that didn’t gain enough mass to shine as a star.
The candidate object was found with ESO’s Very Large Telescope (VLT), using its new Enhanced Resolution Imager and Spectrograph (ERIS). The new ERIS data are shown here in orange, overlaid on older images of the dusty disc as seen with the VLT’s SPHERE instrument (yellow) and the Atacama Large Millimeter/submillimeter Array (ALMA, in blue).
Credit: ESO/A. Dasgupta/ALMA (ESO/NAOJ/NRAO)/Weber et al.
This image, taken with ESO’s Very Large Telescope (VLT), shows a possible companion orbiting the young star V960 Mon. The image was captured with the VLT’s Enhanced Resolution Imager and Spectrograph (ERIS) instrument. The properties of the object are unknown: it could be a planet or a brown dwarf –– an object bigger than a planet that didn’t gain enough mass to shine as a star.
Credit: ESO/A. Dasgupta
The new study, led by Anuroop Dasgupta, a doctoral researcher at ESO and at the Diego Portales University in Chile, follows up observations of V960 Mon made a couple of years ago. Those observations, made with both SPHERE and the Atacama Large Millimeter/submillimeter Array (ALMA), revealed that the material orbiting V960 Mon is shaped into a series of intricate spiral arms. They also showed that the material is fragmenting, in a process known as ‘gravitational instability’, when large clumps of the material around a star contract and collapse, each with the potential to form a planet or a larger object.
“That work revealed unstable material but left open the question of what happens next. With ERIS, we set out to find any compact, luminous fragments signalling the presence of a companion in the disc — and we did,” says Dasgupta.
The team found a potential companion object very near to one of the spiral arms observed with SPHERE and ALMA. The team say that this object could either be a planet in formation, or a ‘brown dwarf’ — an object bigger than a planet that didn’t gain enough mass to shine as a star.
If confirmed, this companion object may be the first clear detection of a planet or brown dwarf forming by gravitational instability.
More information
This research highlighted in the first part of this release was presented in the paper “Unveiling a protoplanet candidate embedded in the HD 135344B disk with VLT/ERIS” to appear in Astronomy & Astrophysics (doi: 10.1051/0004-6361/202554472). The second part of the release highlights the study “VLT/ERIS observations of the V960 Mon system: a dust-embedded substellar object formed by gravitational instability?” published in The Astrophysical Journal Letters (doi: 10.3847/2041-8213/ade996).
The team who conducted the first study (on HD 135344B) is composed of F. Maio (University of Firenze, Italy, and INAF-Osservatorio Astrofisico Arcetri, Firenze, Italy [OAA]), D. Fedele (OAA), V. Roccatagliata (University of Bologna, Italy [UBologna] and OAA), S. Facchini (University of Milan, Italy [UNIMI]), G. Lodato (UNIMI), S. Desidera (INAF-Osservatorio Astronomico di Padova, Italy [OAP]), A. Garufi (INAF – Istituto di Radioastronomia, Bologna, Italy [INAP-Bologna], and Max-Planck-Institut für Astronomie, Heidelberg, Germany [MPA]), D. Mesa (OAP), A. Ruzza (UNIMI), C. Toci (European Southern Observatory [ESO], Garching bei Munchen, Germany, and OAA), L. Testi (OAA, and UBologna), A. Zurlo (Diego Portales University [UDP], Santiago, Chile, and Millennium Nucleus on Young Exoplanets and their Moons [YEMS], Santiago, Chile), and G. Rosotti (UNIMI).
The team behind the second study (on V960 Mon) is primarily composed of members of the Millennium Nucleus on Young Exoplanets and their Moons (YEMS), a collaborative research initiative based in Chile. Core YEMS contributors include A. Dasgupta (ESO, Santiago, Chile, UDP, and YEMS), A. Zurlo (UDP and YEMS), P. Weber (University of Santiago [Usach], Chile, and YEMS, and Center for Interdisciplinary Research in Astrophysics and Space Exploration [CIRAS], Santiago, Chile), F. Maio (OAA, and University of Firenze, Italy), Lucas A. Cieza (UDP and YEMS), D. Fedele (OAA), A. Garufi (INAF Bologna and MPA), J. Miley (Usach, YEMS, and CIRAS), P. Pathak (Indian Institute of Technology, Kanpur, India), S. Pérez (Usach and YEMS, and CIRAS), and V. Roccatagliata (UBologna and OAA).
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
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.
Double detonation: new image shows SNR 0509-67.5, remains of star destroyed by pair of explosions
For the first time, astronomers have obtained visual evidence that a star met its end by detonating twice. By studying the centuries-old remains of supernova SNR 0509-67.5 with the European Southern Observatory’s Very Large Telescope (ESO’s VLT), they have found patterns that confirm its star suffered a pair of explosive blasts. Published today, this discovery shows some of the most important explosions in the Universe in a new light.
This artist’s impression illustrates the supernova remnant SNR 0509-67.5. Observations from ESO’s Very Large Telescope (VLT) show that these are the expanding remains of a star that died with a double-detonation hundreds of years ago. Credit: ESO/M. Kornmesser
Most supernovae are the explosive deaths of massive stars, but one important variety comes from an unassuming source. White dwarfs, the small, inactive cores left over after stars like our Sun burn out their nuclear fuel, can produce what astronomers call a Type Ia supernova.
“The explosions of white dwarfs play a crucial role in astronomy,”
says Priyam Das, a PhD student at the University of New South Wales Canberra, Australia, who led the study on SNR 0509-67.5 published today in Nature Astronomy. Much of our knowledge of how the Universe expands rests on Type Ia supernovae, and they are also the primary source of iron on our planet, including the iron in our blood.
“Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved,” he adds.
All models that explain Type Ia supernovae begin with a white dwarf in a pair of stars. If it orbits close enough to the other star in this pair, the dwarf can steal material from its partner. In the most established theory behind Type Ia supernovae, the white dwarf accumulates matter from its companion until it reaches a critical mass, at which point it undergoes a single explosion. However, recent studies have hinted that at least some Type Ia supernovae could be better explained by a double explosion triggered before the star reached this critical mass.
This image, taken with ESO’s Very Large Telescope (VLT), shows the supernova remnant SNR 0509-67.5. These are the expanding remains of a star that exploded hundreds of years ago in a double-detonation – the first photographic evidence that stars can die with two blasts. The data were captured with the Multi-Unit Spectroscopic Explorer (MUSE) instrument at the VLT. MUSE allows astronomers to map the distribution of different chemical elements, displayed here in different colours. Calcium is shown in blue, and it is arranged in two concentric shells. These two layers indicate that the now-dead star exploded with a double-detonation. Credit: ESO/P. Das et al. Background stars (Hubble): K. Noll et al.
Now, astronomers have captured a new image that proves their hunch was right: at least some Type Ia supernovae explode through a ‘double-detonation’ mechanism instead. In this alternative model, the white dwarf forms a blanket of stolen helium around itself, which can become unstable and ignite. This first explosion generates a shockwave that travels around the white dwarf and inwards, triggering a second detonation in the core of the star — ultimately creating the supernova.
Until now, there had been no clear, visual evidence of a white dwarf undergoing a double detonation. Recently, astronomers have predicted that this process would create a distinctive pattern or fingerprint in the supernova’s still-glowing remains, visible long after the initial explosion. Research suggests that remnants of such a supernova would contain two separate shells of calcium.
Astronomers have now found this fingerprint in a supernova’s remains. Ivo Seitenzahl, who led the observations and was at Germany’s Heidelberg Institute for Theoretical Studies when the study was conducted, says these results show
“a clear indication that white dwarfs can explode well before they reach the famous Chandrasekhar mass limit, and that the ‘double-detonation’ mechanism does indeed occur in nature.”
The team were able to detect these calcium layers (in blue in the image) in the supernova remnant SNR 0509-67.5 by observing it with the Multi Unit Spectroscopic Explorer (MUSE) on ESO’s VLT. This provides strong evidence that a Type Ia supernova can occur before its parent white dwarf reaches a critical mass.
This image shows the distribution of calcium in the supernova remnant SNR 0509-67.5. The data were captured with the Multi-Unit Spectroscopic Explorer (MUSE) instrument at ESO’s Very Large Telescope (VLT). The overlaid curves outline two concentric shells of calcium that were ejected in two separate detonations when the star died several hundred years ago. Credit: ESO/P. Das et al.
Type Ia supernovae are key to our understanding of the Universe. They behave in very consistent ways, and their predictable brightness — no matter how far away they are — helps astronomers to measure distances in space. Using them as a cosmic measuring tape, astronomers discovered the accelerating expansion of the Universe, a discovery that won the Physics Nobel Prize in 2011. Studying how they explode helps us to understand why they have such a predictable brightness.
Das also has another motivation to study these explosions.
“This tangible evidence of a double-detonation not only contributes towards solving a long-standing mystery, but also offers a visual spectacle,” he says, describing the “beautifully layered structure” that a supernova creates. For him, “revealing the inner workings of such a spectacular cosmic explosion is incredibly rewarding.”
This image marks the position on the sky of the supernova remnant SNR 0509-67.5, the expanding shells of a star that detonated twice. It is located 160 000 light-years away in the Large Magellanic Cloud, a small galaxy orbiting our own Milky Way. The inset shows new observations with ESO’s Very Large Telescope (VLT), which show that the original star died with two explosive blasts. The main image shows the VLT unit telescope used in these observations. Credit: ESO/Inset: P. Das et al., background stars (Hubble): K. Noll et al.
More information
This research was presented in a paper titled “Calcium in a supernova remnant shows the fingerprint of a sub-Chandrasekhar mass explosion” to appear in Nature Astronomy at https://www.nature.com/articles/s41550-025-02589-5 (doi: 10.1038/s41550-025-02589-5).
The team is composed of P. Das (University of New South Wales, Australia [UNSW] & Heidelberger Institut für Theoretische Studien, Heidelberg, Germany [HITS]), I. R. Seitenzahl (HITS), A. J. Ruiter (UNSW & HITS & OzGrav: The ARC Centre of Excellence for Gravitational Wave Discovery, Hawthorn, Australia & ARC Centre of Excellence for All-Sky Astrophysics in 3 Dimensions), F. K. Röpke (HITS & Institut für Theoretische Astrophysik, Heidelberg, Germany & Astronomisches Recheninstitut, Heidelberg, Germany), R. Pakmor (Max-Planck-Institut für Astrophysik, Garching, Germany [MPA]), F. P. A. Vogt (Federal Office of Meteorology and Climatology – MeteoSwiss, Payerne, Switzerland), C. E. Collins (The University of Dublin, Dublin, Ireland & GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany), P. Ghavamian (Towson University, Towson, USA), S. A. Sim (Queen’s University Belfast, Belfast, UK), B. J. Williams (X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, USA), S. Taubenberger (MPA & Technical University Munich, Garching, Germany), J. M. Laming (Naval Research Laboratory, Washington, USA), J. Suherli (University of Manitoba, Winnipeg, Canada), R. Sutherland (Australian National University, Weston Creek, Australia), and N. Rodríguez-Segovia (UNSW).
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
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. 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 RamisaThis 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.
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.
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
JWST detected the neutron star merger (kilonova) that generated the explosion that created GRB 230307A and helped detecting the heavy element tellurium
Webb’s study of the second-brightest gamma-ray burst ever seen reveals tellurium.
Under what conditions many chemical elements are created in the universe has long been shrouded in mystery. This includes elements that are highly valuable, or even vital to life as we know it. Astronomers are now one step closer to an answer thanks to the James Webb Space Telescope and a high-energy event: the second-brightest gamma-ray burst ever detected, most likely caused by the merging of two neutron stars—which resulted in an explosion known as a kilonova. Using Webb’s spectacular sensitivity, scientists captured the first mid-infrared spectrum from space of a kilonova, which marked Webb’s first direct look at an individual heavy element from such an event.
A team of scientists has used the NASA/ESA/CSA James Webb Space Telescope to observe an exceptionally bright gamma-ray burst, GRB 230307A, and its associated kilonova. Kilonovas—an explosion produced by a neutron star merging with either a black hole or with another neutron star—are extremely rare, making it difficult to observe these events. The highly sensitive infrared capabilities of Webb helped scientists identify the home address of the two neutron stars that created the kilonova. This image from Webb’s NIRCam (Near-Infrared Camera) instrument highlights GRB 230307A’s kilonova and its former home galaxy among their local environment of other galaxies and foreground stars. The neutron stars were kicked out of their home galaxy and travelled the distance of about 120,000 light-years, approximately the diameter of the Milky Way galaxy, before finally merging several hundred million years later. This image is a composite of separate exposures acquired by the James Webb Space Telescope using the NIRCam instrument. Several filters were used to sample wide wavelength ranges. The colour results from assigning different hues (colours) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colours are: Blue: F115W + F150W Green: F277W Red: F356W + F444W Credit: NASA, ESA, CSA, STScI, A. Levan (IMAPP, Warw), A. Pagan (STScI)
A team of scientists has used multiple space- and ground-based telescopes, including the NASA/ESA/CSA James Webb Space Telescope, to observe an exceptionally bright gamma-ray burst, GRB 230307A, and identify the neutron star merger that generated the explosion that created the burst. Webb also helped scientists detect the chemical element tellurium in the aftermath of the explosion.
Other elements near tellurium on the periodic table — like iodine, which is needed for much of life on Earth — are also likely to be present among the kilonova’s ejected material. A kilonova is an explosion produced by a neutron star merging with either a black hole or with another neutron star.
“Just over 150 years since Dmitri Mendeleev wrote down the periodic table of elements, we are now finally in a position to start filling in those last blanks of understanding where everything was made, thanks to Webb,”
said Andrew Levan of Radboud University in the Netherlands and the University of Warwick in the United Kingdom, lead author of the study.
While neutron star mergers have long been theorised as being the ideal “pressure cookers” to create some of the rarer elements substantially heavier than iron, astronomers have previously encountered a few obstacles to obtaining solid evidence.
This graphic presentation compares the spectral data of GRB 230307A’s kilonova as observed by the James Webb Space Telescope and a kilonova model. Both show a distinct peak in the region of the spectrum associated with tellurium, with the area shaded in red. The detection of tellurium, which is rarer than platinum on Earth, marks Webb’s first direct look at an individual heavy element from a kilonova. Though astronomers have theorised neutron star mergers to be the ideal environment to create chemical elements, including some that are essential to life, these explosive events—known as kilonovas—are rare and rapid. Webb’s NIRSpec (Near-Infrared Spectrograph) acquired a spectrum of GRB 230307A’s kilonova, helping scientists secure evidence of the synthesis of heavy elements from neutron star mergers. With Webb’s extraordinary ability to look further into space than ever before, astronomers expect to find even more kilonovas and acquire further evidence of heavy element creation. Credit: NASA, ESA, CSA, J. Olmsted (STScI)
Kilonovas are extremely rare, making it difficult to observe these events. Short gamma-ray bursts (GRBs), traditionally thought to be those that last less than two seconds, can be byproducts of these infrequent merger episodes. In contrast, long gamma-ray bursts may last several minutes and are usually associated with the explosive death of a massive star.
The case of GRB 230307A is particularly remarkable. First detected by NASA’s Fermi Gamma-ray Space Telescope in March, it is the second brightest GRB observed in over 50 years of observations, about 1000 times brighter than a typical gamma-ray burst that Fermi observes. It also lasted for 200 seconds, placing it firmly in the category of long-duration gamma-ray bursts, despite its different origin.
“This burst is way into the long category. It’s not near the border. But it seems to be coming from a merging neutron star,”
added Eric Burns, a co-author of the paper and member of the Fermi team at Louisiana State University.
The collaboration of many telescopes on the ground and in space allowed scientists to piece together a wealth of information about this event as soon as the burst was detected. It is an example of how satellites and telescopes work together to witness changes in the Universe as they unfold.
After the initial detection, an intensive series of observations from the ground and from space, swung into action to pinpoint the source on the sky and track how its brightness changed. These observations in the gamma-ray, X-ray, optical, infrared, and radio showed that the optical/infrared counterpart was faint, evolved quickly, and became very red – the hallmarks of a kilonova.
“This type of explosion is very rapid, with the material in the explosion also expanding swiftly,” said Om Sharan Salafia, a co-author of the study at the INAF – Brera Astronomical Observatory in Italy. “As the whole cloud expands, the material cools off quickly and the peak of its light becomes visible in the infrared, and becomes redder on timescales of days to weeks.”
At later times it would have been impossible to study this kilonova from the ground, but these were the perfect conditions for Webb’s NIRCam (Near-Infrared Camera) and NIRSpec (Near-Infrared Spectrograph) instruments to observe this tumultuous environment. The spectrum has broad lines that show the material is ejected at high speeds, but one feature is clear: light emitted by tellurium, an element rarer than platinum on Earth.
The highly sensitive infrared capabilities of Webb helped scientists identify the home address of the two neutron stars that created the kilonova: a spiral galaxy about 120,000 light-years away from the site of the merger.
Prior to their venture, they were once two normal massive stars that formed a binary system in their home spiral galaxy. Since the duo was gravitationally bound, both stars were launched together on two separate occasions: when one among the pair exploded as a supernova and became a neutron star, and when the other star followed suit.
A team of scientists has used the NASA/ESA/CSA James Webb Space Telescope to observe an exceptionally bright gamma-ray burst, GRB 230307A, and its associated kilonova. Kilonovas—an explosion produced by a neutron star merging with either a black hole or with another neutron star—are extremely rare, making it difficult to observe these events. The highly sensitive infrared capabilities of Webb helped scientists identify the home address of the two neutron stars that created the kilonova. This image from Webb’s NIRCam (Near-Infrared Camera) instrument highlights GRB 230307A’s kilonova and its former home galaxy among their local environment of other galaxies and foreground stars. The neutron stars were kicked out of their home galaxy and travelled the distance of about 120,000 light-years, approximately the diameter of the Milky Way galaxy, before finally merging several hundred million years later. This image is a composite of separate exposures acquired by the James Webb Space Telescope using the NIRCam instrument. Several filters were used to sample wide wavelength ranges. The colour results from assigning different hues (colours) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colours are: Blue: F115W + F150W Green: F277W Red: F356W + F444W Credit: NASA, ESA, CSA, STScI, A. Levan (IMAPP, Warw), A. Pagan (STScI)
In this case, the neutron stars remained as a binary system despite two explosive jolts and were kicked out of their home galaxy. The pair travelled approximately the equivalent of the Milky Way galaxy’s diameter before merging several hundred million years later.
Scientists expect to find even more kilonovas in the future thanks to the increasing number of opportunities to have space and ground-based telescopes working in complementary ways to study changes in the Universe.
“Webb provides a phenomenal boost and may find even heavier elements,” said Ben Gompertz, a co-author of the study at the University of Birmingham in the United Kingdom. “As we get more frequent observations, the models will improve and the spectrum may evolve more in time. Webb has certainly opened the door to do a lot more, and its abilities will be completely transformative for our understanding of the Universe.”
These findings have been published in the journal Nature.
A team of scientists has used the NASA/ESA/CSA James Webb Space Telescope to observe an exceptionally bright gamma-ray burst, GRB 230307A, and its associated kilonova. Kilonovas—an explosion produced by a neutron star merging with either a black hole or with another neutron star—are extremely rare, making it difficult to observe these events. The highly sensitive infrared capabilities of Webb helped scientists identify the home address of the two neutron stars that created the kilonova. This image from Webb’s NIRCam (Near-Infrared Camera) instrument highlights GRB 230307A’s kilonova and its former home galaxy among their local environment of other galaxies and foreground stars. The neutron stars were kicked out of their home galaxy and travelled the distance of about 120,000 light-years, approximately the diameter of the Milky Way galaxy, before finally merging several hundred million years later. This image is a composite of separate exposures acquired by the James Webb Space Telescope using the NIRCam instrument. Several filters were used to sample wide wavelength ranges. The colour results from assigning different hues (colours) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colours are: Blue: F115W + F150W Green: F277W Red: F356W + F444W Credit: NASA, ESA, CSA, STScI, A. Levan (IMAPP, Warw), A. Pagan (STScI)
