S22B0110

Our new direct imaging survey strategy has successfully demonstrated proof-of-concept discoveries, which are two benchmark brown dwarf companions around Sun-like stars (Currrie et al. 2020; Kuzuhara et al in prep). Our strategy uses proper motion accelerations measured by the combination of the Hipparcos and Gaia astrometry to select high-probability targets as host of co-moving companion, enabling a much more efficient survey than conventional blind surveys. The astrometric indications are sensitive to Jupiter-like companions. We here propose to continue the deep SCExAO/CHARIS imaging to the accelerating targets. This program focuses on older Sun-like stars (age ≃ 200–700 Myr) than our previous surveys to increase the sample of cool (<1000 K) planets. The imaging sensitivities are boosted by longer integrations (= 120 minutes) that can access the planetary-mass regime (<13 M_Jup). This technique is also available to dynamically derive the mass of a detected companion, and the CHARIS observation measures its near-infrared spectrum. Accordingly, even a discovery of brown dwarf becomes a benchmark to constrain atmosphere and evolutionary models for cool objects including planets.

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