The SCExAO Direct Imaging Search for Planets Around Accelerating Stars

We present results from a new exoplanet search combining direct imaging with SCExAO/CHARIS and astrometry from the Gaia and Hipparcos satellites. Our survey targets young stars showing evidence for an astrometric acceleration plausibly due to a planet or brown dwarf companion. CHARIS spectra constrain companion atmospheric properties. Relative astrometry of companions from SCExAO/CHARIS and absolute astrometry of the star from Hipparcos and Gaia together yield direct dynamical mass constraints, circumventing usual challenges in inferring the masses of imaged planets from luminosity evolution models.

Our survey has now produced the first-ever joint discovery of an exoplanet with direct imaging & astrometry and the first exoplanet discovery utilizing Gaia data. We describe this and other discoveries and how companions we find are crucial benchmarks for understanding planet/brown dwarf atmosphere evolution. Our nascent survey yields a higher detection rate than large blind surveys from GPI and SPHERE and prefigures future campaigns to identify, confirm, and characterize exo-Earths from a combination of direct imaging and indirect methods.