A Strip Search for New Very Wide Halo Binaries

TL;DR

This study identifies new wide halo binary star candidates in SDSS Stripe 82, providing a valuable sample for astrophysical research and future surveys, despite limited current constraints on dark matter.

Contribution

The paper presents a new catalog of wide halo binary candidates with proper motion and photometric data, and discusses their implications for binary formation and Galactic evolution.

Findings

Sample of 24 wide halo binary candidates identified.

Wide binary separation function consistent with previous studies.

Estimated increase in binary sample size with upcoming surveys.

Abstract

We report on a search for new wide halo binary stars in SDSS Stripe 82. A list of new halo wide binary candidates which satisfy common proper motion and photometric constraints is provided. The projected separations of the sample lie between 0.007-0.25pc. Although the sample is not large enough to improve constraints on dark matter in the halo, we find the wide binary angular separation function is broadly consistent with past work. We discuss the significance of the new sample for a number of astrophysical applications, including as a testbed for ideas about wide binary formation. For the subset of candidates which have radial velocity information we make use of integrals of motion to investigate one such scheme in which the origin of Galactic wide binaries is associated with the accretion/disruption of stellar systems in the Galaxy. Additional spectroscopic observations of these candidate binaries will strengthen their usefulness in many of these respects. Based on our search experience in Stripe 82 we estimate that the upcoming Pan-STARRS survey will increase the sample size of wide halo binaries by over an order of magnitude.