A Distance-Limited Imaging Survey of Sub-Stellar Companions to Solar Neighborhood Stars

TL;DR

This survey used adaptive optics imaging to search for sub-stellar companions around nearby solar-type stars, achieving high sensitivity but finding no new companions within the surveyed separation range.

Contribution

It presents a new high-sensitivity imaging technique and results from a systematic survey of 21 stars, setting constraints on the presence of sub-stellar companions.

Findings

No new sub-stellar companions detected.

Sensitivity to companions down to 50-75 MJ depending on age.

Survey covers separations of 20-250 AU.

Abstract

We report techniques and results of a Palomar 200-inch (5 m) adaptive optics imaging survey of sub-stellar companions to solar-type stars. The survey consists of Ks coronagraphic observations of 21 FGK dwarfs out to 20 pc (median distance about 17 pc). At 1-arcsec separation (17 projected AU) from a typical target system, the survey achieves median sensitivities 7 mag fainter than the parent star. In terms of companion mass, that corresponds to sensitivities of 50MJ (1 Gyr), 70MJ (solar age), and 75MJ (10 Gyr), using the evolutionary models of Baraffe and colleagues. Using common proper motion to distinguish companions from field stars, we find that no system shows positive evidence of a previously unknown substellar companion (searchable separation about 20-250 projected AU at the median target distance).