Design, scientific goals, and performance of the SCExAO survey for planets around accelerating stars

TL;DR

This paper presents the design and early results of a direct imaging survey targeting stars with astrometric acceleration, aiming to discover planets and brown dwarfs and support the Roman Space Telescope's coronagraphic mission.

Contribution

It introduces a novel survey focusing on accelerating stars, achieving higher discovery rates, and supporting future space telescope missions with a targeted target list.

Findings

Discovered multiple new companions including planets and brown dwarfs.

Higher discovery rate compared to previous unbiased surveys.

Supports the Roman Space Telescope's coronagraphic instrument planning.

Abstract

We describe the motivation, design, and early results for our 42-night, 125 star Subaru/SCExAO direct imaging survey for planets around accelerating stars. Unlike prior large surveys, ours focuses only on stars showing evidence for an astrometric acceleration plausibly due to the dynamical pull of an unseen planet or brown dwarf. Our program is motivated by results from a recent pilot program that found the first planet jointly discovered from direct imaging and astrometry and resulted in a planet and brown dwarf discovery rate substantially higher than previous unbiased surveys like GPIES. The first preliminary results from our program reveal multiple new companions; discovered planets and brown dwarfs can be further characterized with follow-up data, including higher-resolution spectra. Finally, we describe the critical role this program plays in supporting the Roman Space Telescope Coronagraphic Instrument, providing a currently-missing list of targets suitable for the CGI technological demonstration without which the CGI tech demo risks failure.