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Webb images young, giant exoplanets in HR 8799, detects carbon dioxide

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This image shows the planetary system HR 8799. The image background is black. At the centre of the image, there is a symbol representing a star labeled HR 8799. This star blocks the light from the host star. There are four exoplanets, which look like fuzzy dots, pictured in the image surrounding the star. Furthest from the star is a fuzzy, faint blue dot, labeled b, at the 10 o’clock position. At the one o’clock position, second furthest from the star is a blueish-white fuzzy dot labeled c. Just below that is an orange dot labeled e. At the four o’clock position, still nearby the star, is another fuzzy white dot labeled d.

Webb images young, giant exoplanets in HR 8799, detects carbon dioxide

Findings suggest giant exoplanets in HR 8799 system likely formed like Jupiter and Saturn.

The NASA/ESA/CSA James Webb Space Telescope has captured direct images of multiple gas giant planets within an iconic planetary system. HR 8799, a young system 130 light-years away, has long been a key target for planet formation studies.

This image shows the planetary system HR 8799. The image background is black. At the centre of the image, there is a symbol representing a star labeled HR 8799. This star blocks the light from the host star. There are four exoplanets, which look like fuzzy dots, pictured in the image surrounding the star. Furthest from the star is a fuzzy, faint blue dot, labeled b, at the 10 o’clock position. At the one o’clock position, second furthest from the star is a blueish-white fuzzy dot labeled c. Just below that is an orange dot labeled e. At the four o’clock position, still nearby the star, is another fuzzy white dot labeled d.
The NASA/ESA/CSA James Webb Space Telescope has provided the clearest look yet at the iconic multi-planet system HR 8799. The observations detected carbon dioxide in each of the planets, which provides strong evidence that the system’s four giant planets formed much like Jupiter and Saturn, by slowly building solid cores that attract gas from within a protoplanetary disk. Colours are applied to filters from Webb’s NIRCam (Near-Infrared Camera), revealing their intrinsic differences. A star symbol marks the location of the host star HR 8799, whose light has been blocked by a coronagraph. The colours in this image, which represent different wavelengths captured by Webb’s NIRCam, tell researchers about the temperatures and composition of the planets. HR 8799 b, which orbits around 10.1 billion kilometres from the star, is the coldest of the bunch, and the richest in carbon dioxide. HR 8799 e orbits 2.4 billion kilometres from its star, and likely formed closer to the host star, where there were stronger variations in the composition of material. In this image, the colour blue is assigned to 4.1 micron light, green to 4.3 micron light, and red to the 4.6 micron light. Credit: NASA, ESA, CSA, STScI, W. Balmer (JHU), L. Pueyo (STScI), M. Perrin (STScI)

The observations indicate that the well-studied planets of HR 8799 are rich in carbon dioxide gas. This provides strong evidence that the system’s four giant planets formed much like Jupiter and Saturn, by slowly building solid cores that attract gas from within a protoplanetary disk.

The results also confirm that Webb can infer the chemistry of exoplanet atmospheres through imaging. This technique complements Webb’s powerful spectroscopic instruments, which resolve the atmospheric composition.

“By spotting these strong carbon dioxide features, we have shown there is a sizable fraction of heavier elements, like carbon, oxygen, and iron, in these planets’ atmospheres,” said William Balmer, of Johns Hopkins University in Baltimore. “Given what we know about the star they orbit, that likely indicates they formed via core accretion, which is an exciting conclusion for planets that we can directly see.”

Graphic titled “Exoplanet HR 8799 e: Carbon Dioxide in Gas Giant Exoplanet” has three data points with error bars and a best-fit model for low metal content and high metal content on a graph of Amount of Light from the Planet on the y-axis versus Wavelength of Light in microns on x-axis. Y-axis ranges from less light at bottom to more light at top. X-axis ranges from 3.6 to 5.0 microns. Webb NIRCam data consists of 3 points, plotted in red, with white error bars above and below each point. The best-fit models are jagged blue and yellow lines with several broad peaks and valleys. Two features are labeled with vertical columns. From 4.3 microns to nearly 4.4 microns, a green column is labeled Carbon Dioxide CO2. From nearly 4.4 microns to nearly 4.8 microns, a red column is labeled Carbon Monoxoide CO2.
This graph shows a spectrum of one of the planets in the HR 8799 system, HR 8799 e, which displays the amounts of near-infrared light detected from the planet by Webb at different wavelengths.
The blue and yellow lines are a best-fit model for an atmosphere that would be either low or high in metals heavier than helium, including carbon, also known as metallicity. The Webb data is consistent with a high metallicity planet. Spectral fingerprints of carbon dioxide and carbon monoxide appear in data collected by Webb’s NIRCam (Near-Infrared Camera). Credit: NASA, ESA, CSA, STScI, W. Balmer (JHU), L. Pueyo (STScI), M. Perrin (STScI)

Balmer is the lead author of the study announcing the results published today in The Astrophysical Journal. Balmer and his team’s analysis also includes Webb’s observation of a system 97 light-years away called 51 Eridani.

HR 8799 is a young system about 30 million years old, a fraction of our solar system’s 4.6 billion years. Still hot from their tumultuous formation, the planets within HR 8799 emit large amounts of infrared light that give scientists valuable data on how they formed.

Giant planets can take shape in two ways: by slowly building solid cores with heavier elements that attract gas, just like the giants in our solar system, or when particles of gas rapidly coalesce into massive objects from a young star’s cooling disk, which is made mostly of the same kind of material as the star. Knowing which formation model is more common can give scientists clues to distinguish between the types of planets they find in other systems.

“Our hope with this kind of research is to understand our own solar system, life, and ourselves in comparison to other exoplanetary systems, so we can contextualize our existence,” Balmer said. “We want to take pictures of other solar systems and see how they’re similar or different when compared to ours. From there, we can try to get a sense of how weird our solar system really is—or how normal.”

Of the nearly 6,000 exoplanets discovered, few have been directly imaged, as even giant planets are many thousands of times fainter than their stars. The images of HR 8799 and 51 Eridani were made possible by Webb’s NIRCam (Near-Infrared Camera) coronagraph, which blocks light from bright stars to reveal otherwise hidden worlds.

This image shows the exoplanet 51 Eri b. The image is mostly black, with very faint residual red dots apparent in the central region of the image. At the centre of the image, there is a symbol representing a star labeled 51 Eri. This star blocks the light from the host star. To the left of the circle is a fuzzy bright red circle, which is the exoplanet, labeled b.
The NASA/ESA/CSA James Webb Space Telescope’s NIRCam (Near-Infrared Camera) captured this image of Eridani 51 b, a cool, young exoplanet that orbits 17.7 billion kilometres from its star. Its distance is equivalent to a location between the orbits of Neptune and Saturn in our solar system. The observations detected the planet is rich in carbon dioxide, providing strong evidence that the planet formed much like Jupiter and Saturn, by slowly building a solid core that attracted gas from within a protoplanetary disk.
The 51 Eridani system is 96 light-years from Earth. This image includes filters representing 4.1-micron light as red. Credit: NASA, ESA, CSA, STScI, W. Balmer (JHU), L. Pueyo (STScI), M. Perrin (STScI)

This technology allowed the team to look for infrared light emitted by the planets in wavelengths that are absorbed by specific gases. The team found that the four HR 8799 planets contain more heavy elements than previously thought.

“Webb’s unique capabilities are allowing us to explore the wide diversity of these directly-imaged planets for the first time. This gives us important clues as to how such planetary systems have formed.” said Emily Rickman of the European Space Agency, a co-author of the study. “These new observations reiterate how valuable the HR 8799 multi-planet system is as a stepping stone to understand the formation of exoplanetary systems and of our own Solar System.”

The team is paving the way for more detailed observations to determine whether objects they see orbiting other stars are truly giant planets or objects such as brown dwarfs, which form like stars but don’t accumulate enough mass to ignite nuclear fusion.

“We have other lines of evidence that hint at these four HR 8799 planets forming using this bottom-up approach,” said Laurent Pueyo, an astronomer at the Space Telescope Science Institute in Baltimore, who co-led the work. “How common is this for planets we can directly image? We don’t know yet, but we’re proposing more Webb observations to answer that question.”

“We knew Webb could measure colours of the outer planets in directly imaged systems,” added Rémi Soummer, director of STScI’s Russell B. Makidon Optics Lab and former lead for Webb coronagraph operations. “We have been waiting for 10 years to confirm that our finely tuned operations of the telescope would also allow us to access the inner planets. Now the results are in and we can do interesting science with it.”

The NIRCam observations of HR 8799 and 51 Eridani were conducted as part of Guaranteed Time Observations programmes 1194 and 1412 respectively.

Press release from ESA Webb.

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Webb finds carbon source on surface of Jupiter’s moon Europa

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Europa (NIRCam image)

Webb finds carbon source on surface of Jupiter’s moon Europa

Jupiter’s moon Europa is one of a handful of worlds in our Solar System that could potentially harbour conditions suitable for life. Previous research has shown that beneath its water-ice crust lies a salty ocean of liquid water with a rocky seafloor. However, planetary scientists had not confirmed whether or not that ocean contained the chemicals needed for life, particularly carbon.

Europa (NIRCam image)
Webb’s NIRCam (Near Infrared Camera) captured this picture of the surface of Jupiter’s moon Europa. Webb identified carbon dioxide on the icy surface of Europa that likely originated in the moon’s subsurface ocean. This discovery has important implications for the potential habitability of Europa’s ocean. The moon appears mostly blue because it is brighter at shorter infrared wavelengths. The white features correspond with the chaos terrain Powys Regio (left) and Tara Regio (centre and right), which show enhanced carbon dioxide ice on the surface.
Credit:
NASA, ESA, CSA, G. Villanueva (NASA/GSFC), S. Trumbo (Cornell Univ.), A. Pagan (STScI)

Astronomers using data from the NASA/ESA/CSA James Webb Space Telescope have identified carbon dioxide in a specific region on the icy surface of Europa. Analysis indicates that this carbon likely originated in the subsurface ocean and was not delivered by meteorites or other external sources. Moreover, it was deposited on a geologically recent timescale. This discovery has important implications for the potential habitability of Europa’s ocean.

“On Earth, life likes chemical diversity — the more diversity, the better. We’re carbon-based life. Understanding the chemistry of Europa’s ocean will help us determine whether it’s hostile to life as we know it, or whether it might be a good place for life,”

said Geronimo Villanueva of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, lead author of one of two independent papers describing the findings.

“We now think that we have observational evidence that the carbon we see on Europa’s surface came from the ocean. That’s not a trivial thing. Carbon is a biologically essential element,”

added Samantha Trumbo of Cornell University in Ithaca, New York, lead author of the second paper analysing this data.

NASA plans to launch its Europa Clipper spacecraft, which will perform dozens of close flybys of Europa to further investigate whether it could have conditions suitable for life, in October 2024.

A Surface-Ocean Connection

Webb finds that on Europa’s surface, carbon dioxide is most abundant in a region called Tara Regio — a geologically young area of generally resurfaced terrain known as ‘chaos terrain’. The surface ice has been disrupted, and there has likely been an exchange of material between the subsurface ocean and the icy surface.

“Previous observations from the Hubble Space Telescope show evidence for ocean-derived salt in Tara Regio,” explained Trumbo. “Now we’re seeing that carbon dioxide is heavily concentrated there as well. We think this implies that the carbon probably has its ultimate origin in the internal ocean.”

“Scientists are debating to what extent Europa’s ocean connects to its surface. I think that question has been a big driver of Europa exploration,” said Villanueva. “This suggests that we may be able to learn some basic things about the ocean’s composition even before we drill through the ice to get the full picture.”

Both teams identified the carbon dioxide using data from the integral field unit of Webb’s Near-Infrared Spectrograph (NIRSpec). This instrument mode provides spectra with a resolution of 320 x 320 kilometres over a field of view of diameter 3128 kilometres on the surface of Europa, allowing astronomers to determine where specific chemicals are located.

Map of Europa's surface
This graphic shows a map of Europa’s surface with NIRCam (Near Infrared Camera) in the first panel and compositional maps derived from NIRSpec/IFU (Near Infrared Spectrograph’s Integral Field Unit) data in the following three panels. In the compositional maps, the white pixels correspond to carbon dioxide in the large-scale region of disrupted chaos terrain known as Tara Regio (centre and right), with additional concentrations within portions of the chaos region Powys Regio (left). The second and third panels show evidence of crystalline carbon dioxide, while the fourth panel indicates a complexed and amorphous form of carbon dioxide.
Astronomers using Webb have found carbon on the chaos terrain of Tara Regio and Powys Regio. Surface ices in these regions have been disrupted, and there has likely been a relatively recent exchange of material between the subsurface ocean and the icy surface. Carbon, a universal building block for life as we know it, likely originated in Europa’s ocean. The discovery suggests a potentially habitable environment in the salty subsurface ocean of Europa.
The NIRSpec/IFU images appear pixelated because Europa is 10 x 10 pixels across in the detector’s field of view.
Credit:
NASA, ESA, CSA, G. Villanueva (NASA/GSFC), S. Trumbo (Cornell Univ.), A. Pagan (STScI)

Carbon dioxide isn’t stable on Europa’s surface. Therefore, the scientists say it’s likely that it was supplied on a geologically recent timescale — a conclusion bolstered by its concentration in a region of young terrain.

“These observations only took a few minutes of the observatory’s time,”

said Heidi Hammel of the Association of Universities for Research in Astronomy, a Webb interdisciplinary scientist leading Webb’s Cycle 1 Guaranteed Time Observations of the Solar System.

“Even in this short period of time, we were able to do really big science. This work gives a first hint of all the amazing Solar System science we’ll be able to do with Webb.”

Searching for a Plume

Villanueva’s team also looked for evidence of a plume of water vapour erupting from Europa’s surface. Researchers using the NASA/ESA Hubble Space Telescope reported tentative detections of plumes in 2013, 2016, and 2017. However, finding definitive proof has been difficult.

The new Webb data show no evidence of plume activity, which allowed Villanueva’s team to set a strict upper limit on the rate at which material is potentially being ejected. The team stressed, however, that their non-detection does not rule out a plume.

“There is always a possibility that these plumes are variable and that you can only see them at certain times. All we can say with 100% confidence is that we did not detect a plume at Europa when we made these observations with Webb,” said Hammel.

These findings may help inform NASA’s Europa Clipper mission, as well as ESA’s Jupiter Icy Moons Explorer, Juice, which was launched on 14 April 2023. Juice will make detailed observations of the giant gas planet and its three large ocean-bearing moons — Ganymede, Callisto and Europa — with a suite of remote sensing, geophysical and in situ instruments. The mission will characterise these moons as both planetary objects and possible habitats, explore Jupiter’s complex environment in depth, and study the wider Jupiter system as an archetype for gas giants across the Universe.

“This is a great first result of what Webb will bring to the study of Jupiter’s moons,” said co-author Guillaume Cruz-Mermy, formerly of Université Paris-Saclay and current ESA Research Fellow at the European Space Astronomy Centre. “I’m looking forward to seeing what else we can learn about their surface properties from these and future observations.”

The two papers associated with this research will be published in Science on 21 September 2023.

Europa (NIRCam image, cropped)
Webb’s NIRCam (Near Infrared Camera) captured this picture of the surface of Jupiter’s moon Europa. Webb identified carbon dioxide on the icy surface of Europa that likely originated in the moon’s subsurface ocean. This discovery has important implications for the potential habitability of Europa’s ocean. The moon appears mostly blue because it is brighter at shorter infrared wavelengths. The white features correspond with the chaos terrain Powys Regio (left) and Tara Regio (centre and right), which show enhanced carbon dioxide ice on the surface.
Credit:
NASA, ESA, CSA, G. Villanueva (NASA/GSFC), S. Trumbo (Cornell Univ.), A. Pagan (STScI)

 

Press release from ESA Webb.

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Webb discovers methane, carbon dioxide in atmosphere of K2-18 b

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methane carbon dioxide K2-18 b

Webb discovers methane, carbon dioxide in atmosphere of K2-18 b

A new investigation by an international team of astronomers using data from the NASA/ESA/CSA James Webb Space Telescope into K2-18 b, an exoplanet 8.6 times as massive as Earth, has revealed the presence of carbon-bearing molecules including methane and carbon dioxide. The discovery adds to recent studies suggesting that K2-18 b could be a Hycean exoplanet, one which has the potential to possess a hydrogen-rich atmosphere and a water ocean-covered surface.

methane carbon dioxide K2-18 b
This artist’s concept shows what exoplanet K2-18 b could look like based on science data. K2-18 b, an exoplanet 8.6 times as massive as Earth, orbits the cool dwarf star K2-18 in the habitable zone and lies 120 light-years from Earth. A new investigation with the NASA/ESA/CSA James Webb Space Telescope into K2-18 b has revealed the presence of carbon-bearing molecules including methane and carbon dioxide. The abundance of methane and carbon dioxide, and shortage of ammonia, support the hypothesis that there may be an ocean underneath a hydrogen-rich atmosphere in K2-18 b.
Credit:
NASA, CSA, ESA, J. Olmstead (STScI), N. Madhusudhan (Cambridge University)

The first insight into the atmospheric properties of this habitable-zone exoplanet came from observations with the NASA/ESA Hubble Space Telescope, which prompted further studies that have since changed our understanding of the system.

K2-18 b orbits the cool dwarf star K2-18 in the habitable zone and lies 120 light-years from Earth in the constellation Leo. Exoplanets such as K2-18 b, which have sizes between those of Earth and Neptune, are unlike anything in our Solar System. This lack of equivalent nearby planets means that these ‘sub-Neptunes’ are poorly understood, and the nature of their atmospheres is a matter of active debate among astronomers. Exoplanets such as K2-18 b, which have sizes between those of Earth and Neptune, are unlike anything in our Solar System. This lack of analogous nearby planets means that these ‘sub-Neptunes’ are poorly understood and the nature of their atmospheres is a matter of active debate between astronomers. The suggestion that the sub-Neptune K2-18 b could be a Hycean exoplanet is intriguing, as some astronomers believe that these worlds are promising environments to search for evidence for life on exoplanets.

“Our findings underscore the importance of considering diverse habitable environments in the search for life elsewhere,” 

explained Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the paper announcing these results.

“Traditionally, the search for life on exoplanets has focused primarily on smaller rocky planets, but the larger Hycean worlds are significantly more conducive to atmospheric observations.“

The abundance of methane and carbon dioxide, and shortage of ammonia, support the hypothesis that there may be an ocean underneath a hydrogen-rich atmosphere on K2-18 b. These initial Webb observations also provided a possible detection of a molecule called dimethyl sulphide (DMS). On Earth, this is only produced by life. The bulk of the DMS in Earth’s atmosphere is emitted from phytoplankton in marine environments.

The inference of DMS is less robust and requires further validation.

“Upcoming Webb observations should be able to confirm if DMS is indeed present in the atmosphere of K2-18 b at significant levels,” explained Madhusudhan.

While K2-18 b lies in the habitable zone and is now known to harbour carbon-bearing molecules, this does not necessarily mean that the planet can support life. The planet’s large size — with a radius 2.6 times the radius of Earth — means that the planet’s interior likely contains a large mantle of high-pressure ice, like Neptune, but with a thinner hydrogen-rich atmosphere and an ocean surface. Hycean worlds are predicted to have oceans of water. However, it is also possible that the ocean is too hot to be habitable or be liquid.

“Although this kind of planet does not exist in our solar system, sub-Neptunes are the most common type of planet known so far in the galaxy,” explained team member Subhajit Sarkar of Cardiff University. “We have obtained the most detailed spectrum of a habitable-zone sub-Neptune to date, and this allowed us to work out the molecules that exist in its atmosphere.”

Characterising the atmospheres of exoplanets like K2-18 b — meaning identifying their gases and physical conditions — is a very active area in astronomy. However, these planets are outshone — literally — by the glare of their much larger parent stars, which makes exploring exoplanet atmospheres particularly challenging.

The team sidestepped this challenge by analysing light from K2-18 b’s parent star as it passed through the exoplanet’s atmosphere. K2-18 b is a transiting exoplanet, meaning that we can detect a drop in brightness as it passes across the face of its host star. This is how the exoplanet was first discovered. This means that during transits a tiny fraction of starlight will pass through the exoplanet’s atmosphere before reaching telescopes like Webb. The starlight’s passage through the exoplanet atmosphere leaves traces that astronomers can piece together to determine the gases of the exoplanet’s atmosphere.

“This result was only possible because of the extended wavelength range and unprecedented sensitivity of Webb, which enabled robust detection of spectral features with just two transits,” continued Madhusudhan. “For comparison, one transit observation with Webb provided comparable precision to eight observations with Hubble conducted over a few years and in a relatively narrow wavelength range.”

“These results are the product of just two observations of K2-18 b, with many more on the way,” explained team member Savvas Constantinou of the University of Cambridge. “This means our work here is but an early demonstration of what Webb can observe in habitable-zone exoplanets.”

The team now intends to conduct follow-up research with the telescope’s Mid-InfraRed Instrument (MIRI) spectrograph that they hope will further validate their findings and provide new insights into the environmental conditions on K2-18 b.

“Our ultimate goal is the identification of life on a habitable exoplanet, which would transform our understanding of our place in the Universe,” concluded Madhusudhan. “Our findings are a promising step towards a deeper understanding of Hycean worlds in this quest.”

Spectrum of K2-18 b, obtained with Webb’s NIRISS (Near-Infrared Imager and Slitless Spectrograph) and NIRSpec (Near-Infrared Spectrograph), displays an abundance of methane and carbon dioxide in the exoplanet’s atmosphere, as well as a possible detection of a molecule called dimethyl sulfide (DMS). The detection of methane and carbon dioxide, and shortage of ammonia, are consistent with the presence of an ocean underneath a hydrogen-rich atmosphere in K2-18 b. K2-18 b, 8.6 times as massive as Earth, orbits the cool dwarf star K2-18 in the habitable zone and lies 120 light-years from Earth.
Credit:
NASA, CSA, ESA, J. Olmstead (STScI), N. Madhusudhan (Cambridge University)

The team’s results are accepted for publication in The Astrophysical Journal Letters.

Notes

[1] The Habitable Zone is the region around a star where the conditions could potentially be suitable to sustain life on a planet within this region, for example allowing the presence of liquid water on its surface.

Press release from ESA Webb

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Webb spots swirling, gritty clouds on VHS 1256 b, a remote planet

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Exoplanet VHS 1256 b

Webb spots swirling, gritty clouds on VHS 1256 b, a remote planet

Researchers observing with the NASA/ESA/CSA James Webb Space Telescope have pinpointed silicate cloud features in a distant planet’s atmosphere. The atmosphere is constantly rising, mixing, and moving during its 22-hour day, bringing hotter material up and pushing colder material down. The resulting brightness changes are so dramatic that it is the most variable planetary-mass object known to date. The science team also made extraordinarily clear detections of water, methane and carbon monoxide with Webb’s data, and found evidence of carbon dioxide. This is the largest number of molecules ever identified all at once on a planet outside our Solar System.

Exoplanet VHS 1256 b
This illustration conceptualises the swirling clouds identified by the James Webb Space Telescope in the atmosphere of the exoplanet VHS 1256 b. The planet is about 40 light-years away and orbits two stars that are locked in their own tight rotation. Its clouds, which are filled with silicate dust, are constantly rising, mixing, and moving during its 22-hour day.
Credit:
NASA, ESA, CSA, J. Olmsted (STScI)

Catalogued as VHS 1256 b, the planet is about 40 light-years away and orbits not one, but two stars over a 10 000-year period.

“VHS 1256 b is about four times farther from its stars than Pluto is from our Sun, which makes it a great target for Webb,” said science team lead Brittany Miles of the University of Arizona. “That means the planet’s light is not mixed with light from its stars.” Higher up in its atmosphere, where the silicate clouds are churning, temperatures reach a scorching 830 degrees Celsius.

Within those clouds, Webb detected both larger and smaller silicate dust grains, which are shown on a spectrum.

“The finer silicate grains in its atmosphere may be more like tiny particles in smoke,” noted co-author Beth Biller of the University of Edinburgh in the United Kingdom. “The larger grains might be more like very hot, very small sand particles.”

VHS 1256 b has low gravity compared to more massive brown dwarfs [1], which means that its silicate clouds can appear and remain higher in its atmosphere where Webb can detect them. Another reason its skies are so turbulent is the planet’s age. In astronomical terms, it’s quite young. Only 150 million years have passed since it formed — and it will continue to change and cool over billions of years.

Exoplanet VHS 1256 b
A research team led by Brittany Miles of the University of Arizona used two instruments known as spectrographs aboard the James Webb Space Telescope, one on its Near Infrared Spectrograph (NIRSpec) and another on its Mid-Infrared Instrument (MIRI), to observe a vast section of near- to mid-infrared light emitted by the planet VHS 1256 b. They plotted the light on the spectrum, identifying signatures of silicate clouds, water, methane and carbon monoxide. They also found evidence of carbon dioxide.
Credit:
NASA, ESA, CSA, J. Olmsted (STScI), B. Miles (University of Arizona), S. Hinkley (University of Exeter), B. Biller (University of Edinburgh), A. Skemer (University of California, Santa Cruz)

In many ways, the team considers these findings to be the first ‘coins’ pulled out of a spectrum that researchers view as a treasure chest of data. In many ways, they’ve only begun identifying its contents.

“We’ve identified silicates, but a better understanding of which grain sizes and shapes match specific types of clouds is going to take a lot of additional work,” Miles said. “This is not the final word on this planet — it is the beginning of a large-scale modelling effort to fit Webb’s complex data.”

Although all of the features the team observed have been spotted on other planets elsewhere in the Milky Way by other telescopes, other research teams typically identified only one at a time.

“No other telescope has identified so many features at once for a single target,” said co-author Andrew Skemer of the University of California, Santa Cruz. “We’re seeing a lot of molecules in a single spectrum from Webb that detail the planet’s dynamic cloud and weather systems.”

The team came to these conclusions by analysing data known as spectra gathered by two instruments aboard Webb, the Near-Infrared Spectrograph (NIRSpec) and the Mid-Infrared Instrument (MIRI). Since the planet orbits at such a great distance from its stars, the researchers were able to observe it directly, rather than using the transit technique [2] or a coronagraph [3] to take this data.

There will be plenty more to learn about VHS 1256 b in the months and years to come as this team — and others — continue to sift through Webb’s high-resolution infrared data. “There’s a huge return on a very modest amount of telescope time,” Biller added. “With only a few hours of observations, we have what feels like unending potential for additional discoveries.”

What might become of this planet billions of years from now? Since it’s so far from its stars, it will become colder over time, and its skies may transition from cloudy to clear.

The researchers observed VHS 1256 b as part of Webb’s Early Release Science program, which is designed to help transform the astronomical community’s ability to characterise planets and the discs from which they form.

The team’s paper, entitled “The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b,” will be published in The Astrophysical Journal Letters on 22 March.

Press release from ESA Webb.

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Geology

Discovered a correlation between earthquakes and carbon dioxide in the Apennines

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terremoti anidride carbonica Appennino

Discovered a correlation between earthquakes and carbon dioxide in the Apennines

The analysis of ten years of sampling of CO2 dissolved in the groundwaters of the Apennines showed its maximum concentration during intense seismic activity

terremoti anidride carbonica Appennino
Strong free CO2 emission associated with groundwater discharge (San Vittorino plain, Rieti). The emission is located about 30 km far from the epicentre of the April 2009 L’Aquila earthquake.

In the Apennine chain, the emission of CO2 of deep origin appears to be well correlated with the occurrence and evolution of the seismic sequences of the last decade. This is the result of the study ‘Correlation between tectonic CO2 Earth degassing and seismicity is revealed by a ten-year record in the Apennines, Italy‘ conducted by a team of researchers from the Istituto Nazionale di Geofisica e Vulcanologia (INGV, Italy) and the University of Perugia (UNIPG, Italy) just published in ‘Science Advances’.

“For the first time an analysis of geochemical and geophysical data collected from 2009 to 2018 was carried out“, explains Giovanni Chiodini, INGV researcher and coordinator of the study. “Results of this research have shown a correspondence between deep CO2 emissions and seismicity. In periods of intense seismic activity, peaks in the deep CO2 flux are observed, meanwhile they dampen when the seismic energy and the number of earthquakes decrease“.

The Earth releases CO2 of deep origin mainly from volcanoes, although these emissions also occur in seismic areas where there are no active volcanoes. In particular, this phenomenon is more intense in regions characterized by extensional tectonics, such as the area of ​​the Apennines.

“Although the temporal relationships between the occurrence of a seismic event and the release of CO2 are not yet fully understood“, continues Chiodini, “In this study we hypothesize that the evolution of seismicity in the Apennines is modulated by the rise of CO2 accumulated in crustal reservoirs and produced by the partial melting of the plate subducting beneath the mountain chain“.

The continuous large-scale production of CO2 at depth favors the formation of overpressurized reservoirs. “Seismicity in mountain ranges”, add Francesca Di Luccio and Guido Ventura, INGV researchers and co-authors of the study, “could be related to the depressurization of these reservoirs and the consequent release of fluids which, in turn, activate the faults responsible for earthquakes“.

The study was conducted by sampling the high-flow rate springs (tens of thousands of liters per second) located in the vicinity of the epicentral areas of the earthquakes that occurred in central Italy between 2009 and 2018. “These samplings allowed us to characterize the origin of the CO2 dissolved in the water of the aquifers and to quantify the amount of the dissolved deep CO2“, explains Carlo Cardellini, researcher of the Department of Physics and Geology of the University of Perugia, co-author of the discovery.

“The close relationship between the CO2 release and the number and magnitude of the earthquakes, along with the results of previous seismological surveys, indicate that the earthquakes in the Apennines occurred in the last decade are associated with the rise of deeply derived CO2. It is worth mentioning that the amount of CO2 involved is of the same order as that emitted during volcanic eruptions (approximately 1.8 million tons in ten years)”, concludes Chiodini.

Therefore, the results of the study provide evidence on how the fluids derived from the decarbonation of a subducting plate play an important role in the genesis of earthquakes, opening new horizons in the assessment of CO2 emissions at global scale. Finally, this work demonstrates and supports how the modern study of earthquakes requires a multidisciplinary approach in which geochemical, geophysical and geodynamic data need to be integrated.

earthquakes carbon dioxide Apennines
The Apennine earthquakes during 2007-2019 (including the destructive events of 2009 and 2016) were accompanied by evident peaks in the amount of CO2 dissolved and transported by the large Apennine water springs (tonnes per day of CO2 in the diagram)

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Abstract 

Deep CO 2 emissions characterize many non-volcanic, seismically active regions worldwide and the involvement of deep CO 2 in the earthquake cycle is now generally recognized. However, no long-time records of such emissions have been published and the temporal relations between earthquake occurrence and tectonic CO 2 release remain enigmatic. Here we report a ten-year record (2009-2018) of tectonic CO 2 flux in the Apennines (Italy) during intense seismicity. The gas emission correlates with the evolution of the seismic sequences: peaks in the deep CO 2 flux are observed in periods of high seismicity and decays as the energy and number of earthquakes decrease. We propose that the evolution of seismicity is modulated by the ascent of CO 2 accumulated in crustal reservoirs and originating from the melting of subducted carbonates. This large scale, continuous process of CO 2 production favors the formation of overpressurized CO 2 -rich reservoirs potentially able to trigger earthquakes at crustal depth.

Press release on the correlation between earthquakes and carbon dioxide in the Apenninesfrom the Istituto Nazionale di Geofisica e Vulcanologia and the University of Perugia.

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Environmental Science

World can likely capture and store enough carbon dioxide to meet climate targets

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World can likely capture and store enough carbon dioxide to meet climate targets

The world is currently on track to fulfil scenarios on diverting atmospheric CO2 to underground reservoirs, according to a new study by Imperial.

The capture and storage of carbon dioxide (CO2) underground is one of the key components of the Intergovernmental Panel on Climate Change’s (IPCC) reports keeping global warming to less than 2°C above pre-industrial levels by 2100.

Carbon capture and storage (CCS) would be used alongside other interventions such as renewable energy, energy efficiency, and electrification of the transportation sector.

carbon dioxide storage
Picture by Gerd Altmann

The IPCC used models to create around 1,200 technology scenarios whereby climate change targets are met using a mix of these interventions, most of which require the use of CCS.

Their reports are available here and here.

Now a new analysis from Imperial College London suggests that just 2,700 Gigatonnes (Gt) of carbon dioxide (CO2) would be sufficient to meet the IPCC’s global warming targets. This is far less than leading estimates by academic and industry groups of what is available, which suggest there is more than 10,000 Gt of CO2 storage space globally.

It also found that that the current rate of growth in the installed capacity of CCS is on track to meet some of the targets identified in IPCC reports, and that research and commercial efforts should focus on maintaining this growth while identifying enough underground space to store this much CO2.

The findings are published in Energy & Environmental Science.

Capturing carbon

CCS involves trapping CO2 at its emission source, such as fossil-fuel power stations, and storing it underground to keep it from entering the atmosphere. Together with other climate change mitigation strategies, CCS could help the world reach the climate change mitigation goals set out by the IPCC.

However, until now the amount of storage needed has not been specifically quantified.

The research team, led by Dr Christopher Zahasky at Imperial’s Department of Earth Science and Engineering, found that worldwide, there has been 8.6 per cent growth in CCS capacity over the past 20 years, putting us on a trajectory to meet many climate change mitigation scenarios that include CCS as part of the mix.

Dr Zahasky, who is now an assistant professor at the University of Wisconsin-Madison but conducted the work at Imperial, said: “Nearly all IPCC pathways to limit warming to 2°C require tens of Gts of CO2 stored per year by mid-century. However, until now, we didn’t know if these targets were achievable given historic data, or how these targets related to subsurface storage space requirements.

“We found that even the most ambitious scenarios are unlikely to need more than 2,700 Gt of CO2 storage resource globally, much less than the 10,000 Gt of storage resource that leading reports suggest is possible.?Our study shows that if climate change targets are not met by 2100, it won’t be for a lack of carbon capture and storage space.”

Study co-author Dr Samuel Krevor, also from the Department of Earth Science and Engineering, said: “Rather than focus our attention on looking at how much storage space is available, we decided for the first time to evaluate how much subsurface storage resource is actually needed, and how quickly it must be developed, to meet climate change mitigation targets.”

Speed matters

The study has shown for the first time that the maximum storage space needed is only around 2,700 Gt, but that this amount will grow if CCS deployment is delayed. The researchers worked this out by combining data on the past 20 years of growth in CCS, information on historical rates of growth in energy infrastructure, and models commonly used to monitor the depletion of natural resources.

The researchers say that the rate at which CO2 is stored is important in its success in climate change mitigation. The faster CO2 is stored, the less total subsurface storage resource is needed to meet storage targets. This is because it becomes harder to find new reservoirs or make further use of existing reservoirs as they become full.

They found that storing faster and sooner than current deployment might be needed to help governments meet the most ambitious climate change mitigation scenarios identified by the IPCC.

The study also demonstrates how using growth models, a common tool in resource assessment, can help industry and governments to monitor short-term CCS deployment progress and long-term resource requirements.

However, the researchers point out that meeting CCS storage requirements will not be sufficient on its own to meet the IPCC climate change mitigation targets.

Dr Krevor said: “Our analysis shows good news for CCS if we keep up with this trajectory – but there are many other factors in mitigating climate change and its catastrophic effects, like using cleaner energy and transport as well as significantly increasing the efficiency of energy use.”

Funding for this work was provided by ACT ELEGANCY, DETEC (CH), BMWi (DE), RVO (NL), Gassnova (NO), BEIS (UK), Gassco, Equinor and Total, the European Commission under the Horizon 2020 programme, the UK CCS Research Centre and EPSRC.

“Global geologic carbon storage requirements of climate change mitigation scenarios” by Christopher Zahasky and Samuel Krevor, published 21 May 2020 in Energy & Environmental Science.

 

 

 

Press release by Caroline Brogan, from the Imperial College London

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