The First Direct Images of an Exoplanet with JWST

We present JWST Early Release Science (ERS) coronagraphic observations of the super-Jupiter exoplanet, HIP 65426b, with the Near-Infrared Camera (NIRCam) from 2-5 μm, and with the Mid-Infrared Instrument (MIRI) from 11-16 μm. At a separation of ~0.82” (87⁺¹⁰⁸_-31  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 ~1x10^-5 and ~2x10^-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 0.3   beyond separations of ~100 au. Together with existing ground-based near-infrared data, the JWST photometry are well fit by a BT-SETTL atmospheric model from 1-16 μm, and 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_Sun)=-4.31 to -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 characterise the population of exoplanets amenable to high-contrast imaging in greater detail.