SLoWPoKES-II: 100,000 Wide Binaries Identified in SDSS without Proper Motions

TL;DR

The paper introduces SLoWPoKES-II, a large catalog of 105,537 wide binary systems identified from SDSS data without relying on proper motions, revealing diverse populations and potential multiple formation mechanisms.

Contribution

It presents the largest catalog of bona fide wide binaries identified through photometric distances, expanding the known sample and providing insights into their formation and properties.

Findings

Identification of 105,537 wide binaries with low chance alignment probability.

Evidence of multiple populations in the physical separation distribution.

Discovery of 141 M7 or later wide binary candidates, greatly increasing known systems.

Abstract

We present the SLoWPoKES-II catalog of low-mass visual binaries identified from the Sloan Digital Sky Survey by matching photometric distances. The candidate pairs are vetted by comparing the stellar density at their respective Galactic positions to Monte Carlo realizations of a simulated Milky Way. In this way, we are able to identify large numbers of bona fide wide binaries without the need of proper motions. 105,537 visual binaries with angular separations of $\sim$1-20", are identified, each with a probability of chance alignment of $\lesssim$5%. This is the largest catalog of bona fide wide binaries to date, and it contains a diversity of systems---in mass, mass ratios, binary separations, metallicity, and evolutionary states---that should facilitate follow-up studies to characterize the properties of M dwarfs and white dwarfs. There is a subtle but definitive suggestion of multiple populations in the physical separation distribution, supporting earlier findings. We suggest that wide binaries are comprised of multiple populations, most likely representing different formation modes. There are 141 M7 or later wide binary candidates, representing a 7-fold increase in the number currently known. These binaries are too wide to have been formed via the ejection mechanism. Finally, we find that ~6% of spectroscopically confirmed M dwarfs are not included in the SDSS STAR catalog; they are misclassified as extended sources due to the presence of a nearby or partially resolved companion. The SLoWPoKES-II catalog is publicly available to the entire community on the world wide web via the Filtergraph data visualization portal.