A reflective, metal-rich atmosphere for GJ 1214b from its JWST phase curve

Nature Springer Nature 620 (2023) 67-71

Authors:

Eliza M-R Kempton, Michael Zhang, Jacob L Bean, Maria E Steinrueck, Anjali AA Piette, Vivien Parmentier, Isaac Malsky, Michael T Roman, Emily Rauscher, Peter Gao, Taylor J Bell, Qiao Xue, Jake Taylor, Arjun B Savel, Kenneth E Arnold, Matthew C Nixon, Kevin B Stevenson, Megan Mansfield, Sarah Kendrew, Sebastian Zieba, Elsa Ducrot, Achrène Dyrek, Pierre-Olivier Lagage, Keivan G Stassun

Abstract:

There are no planets intermediate in size between Earth and Neptune in our Solar System, yet these objects are found around a substantial fraction of other stars [1]. Population statistics show that close-in planets in this size range bifurcate into two classes based on their radii [2, 3]. It is hypothesized that the group with larger radii (referred to as "sub-Neptunes") is distinguished by having hydrogen-dominated atmospheres that are a few percent of the total mass of the planets [4]. GJ 1214b is an archetype sub-Neptune that has been observed extensively using transmission spectroscopy to test this hypothesis [5-14]. However, themeasured spectra are featureless, and thus inconclusive, due to the presence of high-altitude aerosols in the planet's atmosphere. Here we report a spectroscopic thermal phase curve of GJ 1214b obtained with JWST in the mid-infrared. The dayside and nightside spectra (average brightness temperatures of 553 ± 9 and 437 ± 19 K, respectively) each show >3σ evidence of absorption features, with H2O as the most likely cause in both. The measured global thermal emission implies that GJ 1214b's Bond albedo is 0.51 ± 0.06. Comparison between the spectroscopic phase curve data and three-dimensional models of GJ 1214b reveal a planet with a high metallicity atmosphere blanketed by a thick and highly reflective layer of clouds or haze.

Photochemically produced SO2 in the atmosphere of WASP-39b.

Nature 617:7961 (2023) 483-487

Authors:

Shang-Min Tsai, Elspeth KH Lee, Diana Powell, Peter Gao, Xi Zhang, Julianne Moses, Eric Hébrard, Olivia Venot, Vivien Parmentier, Sean Jordan, Renyu Hu, Munazza K Alam, Lili Alderson, Natalie M Batalha, Jacob L Bean, Björn Benneke, Carver J Bierson, Ryan P Brady, Ludmila Carone, Aarynn L Carter, Katy L Chubb, Julie Inglis, Jérémy Leconte, Michael Line, Mercedes López-Morales, Yamila Miguel, Karan Molaverdikhani, Zafar Rustamkulov, David K Sing, Kevin B Stevenson, Hannah R Wakeford, Jeehyun Yang, Keshav Aggarwal, Robin Baeyens, Saugata Barat, Miguel de Val-Borro, Tansu Daylan, Jonathan J Fortney, Kevin France, Jayesh M Goyal, David Grant, James Kirk, Laura Kreidberg, Amy Louca, Sarah E Moran, Sagnick Mukherjee, Evert Nasedkin, Kazumasa Ohno, Benjamin V Rackham, Seth Redfield, Jake Taylor, Pascal Tremblin, Channon Visscher, Nicole L Wallack, Luis Welbanks, Allison Youngblood, Eva-Maria Ahrer, Natasha E Batalha, Patrick Behr, Zachory K Berta-Thompson, Jasmina Blecic, SL Casewell, Ian JM Crossfield, Nicolas Crouzet, Patricio E Cubillos, Leen Decin, Jean-Michel Désert, Adina D Feinstein, Neale P Gibson, Joseph Harrington, Kevin Heng, Thomas Henning, Eliza M-R Kempton, Jessica Krick, Pierre-Olivier Lagage, Monika Lendl, Joshua D Lothringer, Megan Mansfield, NJ Mayne, Thomas Mikal-Evans, Enric Palle, Everett Schlawin, Oliver Shorttle, Peter J Wheatley, Sergei N Yurchenko

Abstract:

Photochemistry is a fundamental process of planetary atmospheres that regulates the atmospheric composition and stability1. However, no unambiguous photochemical products have been detected in exoplanet atmospheres so far. Recent observations from the JWST Transiting Exoplanet Community Early Release Science Program2,3 found a spectral absorption feature at 4.05 μm arising from sulfur dioxide (SO2) in the atmosphere of WASP-39b. WASP-39b is a 1.27-Jupiter-radii, Saturn-mass (0.28 MJ) gas giant exoplanet orbiting a Sun-like star with an equilibrium temperature of around 1,100 K (ref. 4). The most plausible way of generating SO2 in such an atmosphere is through photochemical processes5,6. Here we show that the SO2 distribution computed by a suite of photochemical models robustly explains the 4.05-μm spectral feature identified by JWST transmission observations7 with NIRSpec PRISM (2.7σ)8 and G395H (4.5σ)9. SO2 is produced by successive oxidation of sulfur radicals freed when hydrogen sulfide (H2S) is destroyed. The sensitivity of the SO2 feature to the enrichment of the atmosphere by heavy elements (metallicity) suggests that it can be used as a tracer of atmospheric properties, with WASP-39b exhibiting an inferred metallicity of about 10× solar. We further point out that SO2 also shows observable features at ultraviolet and thermal infrared wavelengths not available from the existing observations.

A High Spatial and Spectral Resolution Study of Jupiter's Mid-infrared Auroral Emissions and Their Response to a Solar Wind Compression

PLANETARY SCIENCE JOURNAL 4:4 (2023) ARTN 76

Authors:

James A Sinclair, Thomas K Greathouse, Rohini S Giles, John Lacy, Julianne Moses, Vincent Hue, Denis Grodent, Bertrand Bonfond, Chihiro Tao, Thibault Cavalie, Emma K Dahl, Glenn S Orton, Leigh N Fletcher, Patrick GJ Irwin

Carbon monoxide emission lines reveal an inverted atmosphere in the ultra hot Jupiter WASP-33 b consistent with an eastward hot spot

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 522:2 (2023) 2145-2170

Authors:

Lennart van Sluijs, Jayne L Birkby, Joshua Lothringer, Elspeth KH Lee, Ian JM Crossfield, Vivien Parmentier, Matteo Brogi, Craig Kulesa, Don McCarthy, David Charbonneau

The Roasting Marshmallows Program with IGRINS on Gemini South I: Composition and Climate of the Ultrahot Jupiter WASP-18 b

The Astronomical Journal American Astronomical Society 165:3 (2023) 91

Authors:

Matteo Brogi, Vanessa Emeka-Okafor, Michael R Line, Siddharth Gandhi, Lorenzo Pino, Eliza M-R Kempton, Emily Rauscher, Vivien Parmentier, Jacob L Bean, Gregory N Mace, Nicolas B Cowan, Evgenya Shkolnik, Joost P Wardenier, Megan Mansfield, Luis Welbanks, Peter Smith, Jonathan J Fortney, Jayne L Birkby, Joseph A Zalesky, Lisa Dang, Jennifer Patience, Jean-Michel Désert