The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems I: High-contrast Imaging of the Exoplanet HIP 65426 b from 2 to 16 μm
Authors: Carter Aarynn L. , Hinkley Sasha , Kammerer Jens , Skemer Andrew , Biller Beth A. , Leisenring Jarron M. , Millar-Blanchaer Maxwell A. , Petrus Simon , Stone Jordan M. , Ward-Duong Kimberly , Wang Jason J. , Girard Julien H. , Hines Dean C. , Perrin Marshall D. , Pueyo Laurent , Balmer William O. , Bonavita Mariangela , Bonnefoy Mickael , Chauvin Gael , Choquet Elodie , Christiaens Valentin , Danielski Camilla , Kennedy Grant M. , Matthews Elisabeth C. , Miles Brittany E. , Patapis Polychronis , Ray Shrishmoy , Rickman Emily , Sallum Steph , Stapelfeldt Karl R. , Whiteford Niall , Zhou Yifan , Absil Olivier , Boccaletti Anthony , Booth Mark , Bowler Brendan P. , Chen Christine H. , Currie Thayne , Fortney Jonathan J. , Grady Carol A. , Greebaum Alexandra Z. , Henning Thomas , Hoch Kielan K. W. , Janson Markus , Kalas Paul , Kenworthy Matthew A. , Kervella Pierre , Kraus Adam L. , Lagage Pierre-Olivier , Liu Michael C. , Macintosh Bruce , Marino Sebastian , Marley Mark S. , Marois Christian , Matthews Brenda C. , Mawet Dimitri , McElwain Michael W. , Metchev Stanimir , Meyer Michael R. , Molliere Paul , Moran Sarah E. , Morley Caroline V. , Mukherjee Sagnick , Pantin Eric , Quirrenbach Andreas , Rebollido Isabel , Ren Bin B. , Schneider Glenn , Vasist Malavika , Worthen Kadin , Wyatt Mark C. , Briesemeister Zackery W. , Bryan Marta L. , Calissendorff Per , Cantalloube Faustine , Cugno Gabriele , De Furio Matthew , Dupuy Trent J. , Factor Samuel M. , Faherty Jacqueline K. , Fitzgerald Michael P. , Franson Kyle , Gonzales Eileen C. , Hood Callie E. , Howe Alex R. , Kuzuhara Masayuki , Lagrange Anne-Marie , Lawson Kellen , Lazzoni Cecilia , Lew Ben W. P. , Liu Pengyu , Llop-Sayson Jorge , Lloyd James P. , Martinez Raquel A. , Mazoyer Johan , Palma-Bifani Paulina , Quanz Sascha P. , Redai Jea Adams , Samland Matthias , Schlieder Joshua E. , Tamura Motohide , Tan Xianyu , Uyama Taichi , Vigan Arthur , Vos Johanna M. , Wagner Kevin , Wolff Schuyler G. , Ygouf Marie , Zhang Xi , Zhang Keming , Zhang Zhoujian 
Published: July 2023

Abstract
We present JWST Early Release Science coronagraphic observations of the super-Jupiter exoplanet, HIP 65426b, with the Near-Infrared Camera (NIRCam) from 2 to 5 μm, and with the Mid-Infrared Instrument (MIRI) from 11 to 16 μm. At a separation of ∼0.″82 (87

−
31

+
108

au), HIP 65426b is clearly detected in all seven of our observational filters, representing the first images of an exoplanet to be obtained by JWST, and the first-ever direct detection of an exoplanet beyond 5 μm. These observations demonstrate that JWST is exceeding its nominal predicted performance by up to a factor of 10, depending on separation and subtraction method, with measured 5σ contrast limits of ∼1 × 10−5 and ∼2 × 10−4 at 1″ for NIRCam at 4.4 μm and MIRI at 11.3 μm, respectively. These contrast limits provide sensitivity to sub-Jupiter companions with masses as low as 0.3M
Jup beyond separations of ∼100 au. Together with existing ground-based near-infrared data, the JWST photometry are fit well by a BT-SETTL atmospheric model from 1 to 16 μm, and they span ∼97% of HIP 65426b's luminous range. Independent of the choice of model atmosphere, we measure an empirical bolometric luminosity that is tightly constrained between

log

L

bol

/

L

⊙

= −4.31 and −4.14, which in turn provides a robust mass constraint of 7.1 ± 1.2 M
Jup. In totality, these observations confirm that JWST presents a powerful and exciting opportunity to characterize the population of exoplanets amenable to high-contrast imaging in greater detail.