The SLoWPoKES Catalog of Low-mass Ultra-wide Binaries: A Cool Stars Resource for Testing Fundamental Properties and for Constraining Binary Formation Theory

TL;DR

The SLoWPoKES catalog provides a large, diverse sample of low-mass ultra-wide binaries, enabling studies of stellar properties and binary formation mechanisms through follow-up observations and analysis.

Contribution

This work presents the largest catalog of low-mass, ultra-wide binaries, with a new Galactic model for selection and a recalibrated metallicity index, facilitating stellar and formation studies.

Findings

Diverse properties of binary pairs suggest multiple formation modes.

The catalog contains 1342 systems, the largest of its kind.

New metallicity calibration improves abundance measurements.

Abstract

We present results from the Sloan Low-mass Wide Pairs of Kinematically Equivalent Stars (SLoWPoKES) catalog of ultra-wide (10^3-10^5.5 AU), low-mass (K5-M7) common proper motion binaries. We constructed a Galactic model, based on empirical stellar number density and 3D velocity distributions, to select bona fide pairs with probability of chance alignment <5%, making SLoWPoKES an efficient sample for followup observations. Our initial catalog contains 1342 disk dwarf, subdwarf, and white dwarf-red dwarf systems and is the largest collection of low-mass, wide binaries ever assembled. The diversity---in mass, metallicity, age, and evolutionary states---of SLoWPoKES pairs makes it a valuable resource of coeval laboratories to examine and constrain the physical properties of low-mass stars. SLoWPoKES pairs show signatures of two (or more) formation modes in the distribution of the physical separation and higher-order multiplicity. Neither dynamical dissipation of primordial triples/quadruples or dynamical capture of ejected stars can explain the observed populations by itself. We use followup spectroscopic observations to recalibrate the metallicity-sensitive {\zeta}_(TiO/CaH) index by assuming that both members of the binary system have the same composition. Our new formulation is a significantly better tracer of absolute metallicity, particularly for the early-type M dwarfs. The SLoWPoKES catalog is publicly available on a custom data visualization portal.