Program: GS-2022B-Q-313

In Gaia eDR3, an excess of pairs of stars with small angular separations (<0.4") have been observed. Most of these pairs do not have full astrometric solutions, making it difficult to distinguish between true companions, background sources and spurious detections. Using photometry from various surveys however, we demonstrate that these new detections are consistent with physical companions. Here we utilize photometry from 2MASS and Gaia, where at small angular separations two stars would be unresolved in 2MASS while resolved by Gaia. Due to this difference in resolution, if a close neighbor in Gaia is a physical binary, the associated 2MASS source will have a predictable excess in the J-band that depends on the G-magnitude difference of the stars that is distinct from the relationship for a neighbor that is a random field star. Using these differing relationships, we determine probabilities of close pairs to be binary systems. Here we propose to observe 20 faint candidate binaries with physical separations <30 AU that have not been previously identified, or observed with high resolution imaging. With these observations, we hope to confirm their binary status and assess the validity of our method, and begin to map out the orbits of these systems.