JWST-TST High Contrast: JWST/NIRCam Observations of the Young Giant Planet Β Pic B

We present the first JWST/NIRCam observations of the directly-imaged gasgiant exoplanet β Pic b. Observations in six filters using NIRCam's roundcoronagraphic masks provide a high signal-to-noise detection of β Pic band the archetypal debris disk around β Pic over a wavelength range of∼1.7-5 μm. This paper focuses on the detection of β Pic b andother potential point sources in the NIRCam data, following a paper byRebollido et al. which presented the NIRCam and MIRI view of the debris diskaround β Pic. We develop and validate approaches for obtaining accuratephotometry of planets in the presence of bright, complex circumstellarbackgrounds. By simultaneously fitting the planet's PSF and a geometric modelfor the disk, we obtain planet photometry that is in good agreement withprevious measurements from the ground. The NIRCam data supports the cloudynature of β Pic b's atmosphere and the discrepancy between its mass asinferred from evolutionary models and the dynamical mass reported in theliterature. We further identify five additional localized sources in the data,but all of them are found to be background stars or galaxies based on theircolor or spatial extent. We can rule out additional planets in the diskmidplane above 1 Jupiter mass outward of 2 arcsec (∼40 au) and away fromthe disk midplane above 0.05 Jupiter masses outward of 4 arcsec (∼80 au).The inner giant planet β Pic c remains undetected behind thecoronagraphic masks of NIRCam in our observations.