The Power of Dynamical Masses: a JWST and VLTI/GRAVITY Direct Imaging Survey for Exoplanets

To date, the vast majority of extrasolar planets (planets that orbit stars other than our own sun) have been detected only indirectly, by measuring some effect the have on their host stars. However, the technique of exoplanet direct imaging relies on spatially separating the light of the host star and the extremely faint planet, and is thus naturally suited to direct characterisation of the planets themselves. This technique now has the power to provide extremely powerful constraints on exoplanet formation mechanisms via precise composition measurements, and with the high priority of characterising the luminosities and early thermal histories of young exoplanets, direct imaging is thus also the most direct path to placing powerful constraints on the complex physics inherent in the planet formation process. In this program. In this program we propose a dedicated effort using the leading ground- and space-based observational platforms such as the recently launched JWST and the GRAVITY+ instrument at the Very Large Telescope Interferometer to measure dynamical masses of exoplanets orbiting nearby stars. Since all of our target stars show unambiguous dynamical evidence for planets, this approach will be much more effective than the previous "blind" direct imaging searches. The driving scientific goal of this proposal is to use JWST and GRAVITY to derive precise measurements of the dynamical masses of these planets that, when combined with measurements of the brightness of these objects, will give the best-ever constraints on evolutionary models and the early thermal histories of these objects.