NASA’s Webb Unravels the Mysteries of Planet VHS 1256 b’s Silicate Clouds
Weather report: Scattered silicate clouds are expected at planet VHS 1256 b.
Have you ever had hot sand whipped across your face? This is a calming experience compared to the unstable conditions detected high in the atmosphere of the planet VHS 1256 b. Researchers using NASA’s James Webb Space Telescope proved that its clouds are made up of silicate particles, ranging from fine droplets to tiny grains. Plus, its almost constant cloud cover is moving! The team projects that silicates swirling in these clouds periodically become very heavy and rain down deep into the planet’s atmosphere. Webb’s observations also show clear signs of water, methane and carbon monoxide, and provide evidence for carbon dioxide. This is just the beginning of the team’s research – many more findings are expected as they continue to dig into Webb’s data “sweep”.
NASA’s Webb Space Telescope spots swirling, solid clouds on distant planet
Researchers observing with NASA’s James Webb Space Telescope have noted features of silicate clouds in the atmosphere of a distant planet. The atmosphere is constantly rising, mixing and moving during its 22-hour day, bringing hotter material up and pushing cooler material down. The resulting brightness changes are so dramatic that it is the most variable planetary-mass object known to date. The team, led by Brittany Miles of the University of Arizona, also made remarkably 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.
Cataloged as VHS 1256 b, the planet is about 40 light-years away and orbits not one but two stars over a period of 10,000 years. “VHS 1256 b is about four times farther from its star than Pluto is from our Sun, which makes it an excellent target for Webb,” Miles said. “This means that the light of the planet is not mixed with the light of its stars.” Higher in its atmosphere, where the silicate clouds are erupting, temperatures reach 1,500 degrees Fahrenheit (830 degrees Celsius).
Within those clouds, Webb discovered larger and smaller silicate dust grains, which appear in a spectrum. “The finer silicate grains in its atmosphere may be more like tiny particles in the smoke,” noted co-author Beth Biller of the University of Edinburgh in Scotland. “Larger grains can be more like very hot, very small grains of sand.”
VHS 1256 b has low gravity compared to more massive brown dwarfs, which means 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 is quite young. It’s only been 150 million years since it formed – and it will continue to change and cool over billions of years.
In many ways, the team considers these findings to be the first “coins” mined from a spectrum that researchers see as a treasure trove of data. In many ways, they are just beginning to identify its content. “We have identified silicates, but better understanding what grain sizes and shapes match specific cloud types will require a lot of additional work,” Miles said. “This isn’t the last word on this planet—it’s the start of a large-scale modeling effort to fit Webb’s complex data.”
Although all the features the team observed have been seen on other planets elsewhere in the Milky Way by other telescopes, other research teams usually identified only one at a time. “No other telescope has identified so many features simultaneously for a single target,” said co-author Andrew Skemer of the University of California, Santa Cruz. “We’re seeing many molecules in a single spectrum from Webb that detail the planet’s dynamic cloud and weather systems.”
The team reached these conclusions by analyzing data known as spectra collected 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 star, researchers were able to observe it directly, rather than using the transit technique or a coronagraph to obtain this data.
There will be much more to learn about VHS 1256 b in the coming months and years as this team – and others – continue to analyze Webb’s high-resolution infrared data. “There’s a huge return on a very modest amount of telescope time,” Biller added. “With just a few hours of observations, we have what seems like endless potential for additional discoveries.”
What can be done with this planet billions of years from now? Since it is so far from its stars, it will become cooler over time and its sky may change 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 characterize planets and the disks in which they form.
The team’s paper, titled “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,” was published in The Astrophysical Journal Letters on March 22.
Reference: “JWST Early Launch Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 micron spectrum of the planetary companion VHS 1256-1257 b” by Brittany E. Miles, Beth A. Biller, Polychronis Patapis , Polychronis Patapis, Worthen, Emily Rickman, Kielan KW Hoch, Andrew Skemer, Marshall D. Perrin, Niall Whiteford, Christine H. Chen, Sagnick Mukherjee, Caroline V. Morley, Sarah E. Moran, Mickael Bonnefoy, Simon Petrus, Aarynn L. .Carter, Elodie Choquet, Sasha Hinkley, Kimberly Ward-Duong, Jarron M. Leisenring, Maxwell A. Millar-Blanchaer, Laurent Pueyo, Shrishmoy Ray, Karl R. Stapelfeldt, Jordan M. Stone, Jason J. Wang, Olivier Absil, William O. Balmer, Anthony Boccaleti, Mariangela Bonavita, Mark Booth, Brendan P. Bowler, Gael Chauvin, Valentin Christiaens, Thayne Currie, Camilla Danielski, Jonathan J. Fortney, Julien H. Girard, Alexandra Z. Greenbaum, Thomas Henning, Dean C. Hines, Markus Janson, Paul Kalas, Jens Kammerer, Matth ew A. Kenworthy, Pierre Kervella, Pier re-Olivier Lagage, Ben WP Lew, Michael C. Liu, Bruce Macintosh, Sebastian Marino, Mark S. Marley, Christian Marois, Elisabeth C. Matthews, Brenda C. Matthews, Dimitri Mawet, Michael W. McElwain, Stanimir Metchev, Michael R. Meyer, Paul Molliere, Eric Pantin, Andreas Quirrenbachm Isabel Rebollido, Bin B. Ren, Malavika Vasist, Mark C. Wyatt, Yifan Zhou, Zackery W. Briesemeister, Marta L. Bryan, Per Calissendorff, Faustine Catalloube, Gabriele Cugno, Matthew De Furio, Trent J. Dupuy, Samuel M. Factor, Jacqueline K. Faherty, Michael P. Fitzgerald, Kyle Franson, Eileen C. Gonzales, Callie E. Hood, Alex R. Howe , Adam L. Kraus, Masayuki Kuzuhara, Kellen Lawson, Cecilia Lazzoni, Pengyu Liu, Jorge Llop-Sayson, James P. Lloyd, Raquel A. Martinez, Johan Mazoyer, Sascha P. Quanz, Jea Adams Redai, Matthias Samland, Joshua E. Schlieder, Motohide Tamura, Xianyuan, Taichi Uyama, Arthur Vigan, Johanna M. Vos, Kevin Wagner, Schuyler G. Wolff, Marie Ygouf, Keming Zh ang and Zhoujian Zhang March 22, 2023, The Astrophysical Journal Letters.
The James Webb Space Telescope stands as the premier global space science observatory. Charged with unraveling puzzles within our solar system, exploring distant worlds orbiting other stars, and probing the enigmatic structures and origins of our universe, Webb seeks to understand our role within it. This international effort is led by NASA in collaboration with its partners, the European Space Agency (ESA) and the Canadian Space Agency.