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
Creators: name: Miles, Brittany E.
name: Biller, Beth A.
name: Patapis, Polychronis
name: Worthen, Kadin
name: Rickman, Emily
name: Hoch, Kielan K. W.
name: Skemer, Andrew
name: Perrin, Marshall D.
name: Whiteford, Niall
name: Chen, Christine H.
name: Sargent, B.
name: Mukherjee, Sagnick
name: Morley, Caroline V.
name: Moran, Sarah E.
name: Bonnefoy, Mickael
name: Petrus, Simon
name: Carter, Aarynn L.
name: Choquet, Elodie
name: Hinkley, Sasha
name: Ward-Duong, Kimberly
name: Leisenring, Jarron M.
name: Millar-Blanchaer, Maxwell A.
name: Pueyo, Laurent
name: Ray, Shrishmoy
name: Stapelfeldt, Karl R.
name: Stone, Jordan M.
name: Wang, Jason J.
name: Absil, Olivier
name: Balmer, William O.
name: Boccaletti, Anthony
name: Bonavita, Mariangela
name: Booth, Mark
name: Bowler, Brendan P.
name: Chauvin, Gael
name: Christiaens, Valentin
name: Currie, Thayne
name: Danielski, Camilla
name: Fortney, Jonathan J.
name: Girard, Julien H.
name: Greenbaum, Alexandra Z.
name: Henning, Thomas
name: Hines, Dean C.
name: Janson, Markus
name: Kalas, Paul
name: Kammerer, Jens
name: Kenworthy, Matthew A.
name: Kervella, Pierre
name: Lagage, Pierre-Olivier
name: Lew, Ben W. P.
name: Liu, Michael C.
name: Macintosh, Bruce
name: Marino, Sebastian
name: Marley, Mark S.
name: Marois, Christian
name: Matthews, Elisabeth C.
name: Matthews, Brenda C.
name: Mawet, Dimitri
name: McElwain, Michael W.
name: Metchev, Stanimir
name: Meyer, Michael R.
name: Molliere, Paul
name: Pantin, Eric
name: Rebollido, Andreas Quirrenbachm Isabel
name: Ren, Bin B.
name: Vasist, Malavika
name: Wyatt, Mark C.
name: Zhou, Yifan
name: Briesemeister, Zackery W.
name: Bryan, Marta L.
name: Calissendorff, Per
name: Catalloube, Faustine
name: Cugno, Gabriele
name: De Furio, Matthew
name: Dupuy, Trent J.
name: Factor, Samuel M.
name: Faherty, Jacqueline K.
name: Fitzgerald, Michael P.
name: Franson, Kyle
name: Gonzales, Eileen C.
name: Hood, Callie E.
name: Howe, Alex R.
name: Kraus, Adam L.
name: Kuzuhara, Masayuki
name: Lawson, Kellen
name: Lazzoni, Cecilia
name: Liu, Pengyu
name: Llop-Sayson, Jorge
name: Lloyd, James P.
name: Martinez, Raquel A.
name: Mazoyer, Johan
name: Quanz, Sascha P.
name: Redai, Jea Adams
name: Samland, Matthias
name: Schlieder, Joshua E.
name: Tamura, Motohide
name: Tan, Xianyu
name: Uyama, Taichi
name: Vigan, Arthur
name: Vos, Johanna M.
name: Wagner, Kevin
name: Wolff, Schuyler G.
name: Ygouf, Marie
name: Zhang, Keming
name: Zhang, Zhoujian
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is a $&lt;$20 M$_\mathrm{Jup}$ widely separated ($\sim$8\arcsec, a = 150 au), young, planetary-mass companion that shares photometric colors and spectroscopic features with the directly imaged exoplanets HR 8799 c, d, and e. As an L-to-T transition object, VHS 1256 b exists along the region of the color-magnitude diagram where substellar atmospheres transition from cloudy to clear. We observed VHS 1256~b with \textit{JWST}'s NIRSpec IFU and MIRI MRS modes for coverage from 1 $μ$m to 20 $μ$m at resolutions of $\sim$1,000 - 3,700. Water, methane, carbon monoxide, carbon dioxide, sodium, and potassium are observed in several portions of the \textit{JWST} spectrum based on comparisons from template brown dwarf spectra, molecular opacities, and atmospheric models. The spectral shape of VHS 1256 b is influenced by disequilibrium chemistry and clouds. We directly detect silicate clouds, the first such detection reported for a planetary-mass companion.
description: Accepted ApJL. Iterations of spectra reduced by the ERS team are hosted at this link: https://github.com/bemiles/JWST_VHS1256b_Reduction/tree/main/reduced_spectra