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 mu m

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 mu m, and with the Mid-Infrared Instrument (MIRI) from 11 to 16 mu m. At a separation of similar to 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 mu m. 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 5 sigma contrast limits of similar to 1 x 10(-5) and similar to 2 x 10(-4) at 1" for NIRCam at 4.4 mu m and MIRI at 11.3 mu m, respectively. These contrast limits provide sensitivity to sub-Jupiter companions with masses as low as 0.3M(Jup) beyond separations of similar to 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 mu m, and they span similar to 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-circle dot) = -4.31 and -4.14, which in turn provides a robust mass constraint of 7.1 +/- 1.2M(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.