JWST/NIRCam 4–5 µm Imaging of the Giant Planet AF Lep b
Salama, Maïssa; Perrin, Marshall D.; Pueyo, Laurent; Crepp, Justin R.; Zhou, Yifan; Bardalez Gagliuffi, Daniella C.; Morley, Caroline V.; Tran, Quang H.; Bowler, Brendan P.; Ginski, Christian; Brandt, Timothy D.; Faherty, Jacqueline; Horch, Elliott P.; Balmer, William O.; Rickman, Emily; Mukherjee, Sagnick; Franson, Kyle; Zhang, Zhoujian; Morgan, Marvin; Theissen, Christopher A.; Sanghi, Aniket; Pearce, Tim D.; Davidson, James W.; Bowens-Rubin, Rachel; Biddle, Lauren I.; Wolf, Trevor N.
United States, United Kingdom, Ireland
Abstract
With a dynamical mass of 3 M Jup, the recently discovered giant planet AF Lep b is the lowest-mass imaged planet with a direct mass measurement. Its youth and spectral type near the L/T transition make it a promising target to study the impact of clouds and atmospheric chemistry at low surface gravities. In this work, we present JWST/NIRCam imaging of AF Lep b. Across two epochs, we detect AF Lep b in F444W (4.4 μm) with signal-to-noise ratios of 9.6 and 8.7, respectively. At the planet's separation of 320 mas during the observations, the coronagraphic throughput is ≈7%, demonstrating that NIRCam's excellent sensitivity persists down to small separations. The F444W photometry of AF Lep b affirms the presence of disequilibrium carbon chemistry and enhanced atmospheric metallicity. These observations also place deep limits on wider-separation planets in the system, ruling out 1.1 M Jup planets beyond 15.6 au (0.″58), 1.1 M Sat planets beyond 27 au (1″), and 2.8 M Nep planets beyond 67 au (2.″5). We also present new Keck/NIRC2