Presentation #101.05 in the session Early Results from JWST - I.
In this talk I will present how our JWST Early Release Science (ERS) program executed the imaging and spectroscopy of exoplanetary systems. Our 55-hour program has provided some of the first examples of the high contrast imaging modes of JWST, resulting in the first-ever direct observations of an exoplanet at wavelengths longer than 5 microns. Furthermore, our program has also obtained the highest fidelity spectrum to date of a planetary mass object, showing evidence for disequilibrium chemistry, as well as the first-ever definitive direct detection of silicate clouds in the atmosphere of a planetary mass companion. Our coronagraphic observations demonstrate that JWST is exceeding its nominal predicted performance by up to an order-of-magnitude in some cases, and JWST’s unprecedented sensitivity will make sub-Jupiter extrasolar planets (analogues of our own ice giant planets) accessible for direct characterisation for the first time. In addition to this, the program also entailed some of the first aperture masking interferometry (AMI) observations from space. The observations probed close-in separations (~10-20 au) around the star HIP 65426, a region inaccessible with conventional coronagraphs on JWST. This is a testament to this mode’s unique capability to image close-in planetary mass companions of stars in star forming regions and young moving groups. We have also observed the multi-ringed circumstellar disk HD 141569A using coronagraphic imaging modes, to search for water ice absorption and detect the thermal emission in each of the rings. Finally, alongside the development of several public data processing tools, our program has also allowed us to make clear recommendations to the community of best observing practices going forward, both of which will allow our community to put forward the best possible proposals in future JWST cycles.