Catalogs of Wide Binaries: Impact on Galactic Astronomy

Abstract

Abstract.Wide binaries, particularly in large numbers and as free from selection biases as possible, constitute a largely overlooked tool for studying the Galaxy. The goal of this review is to highlight the potential inherent to large samples of field wide binaries for research on problems as varied as star formation in the early Galaxy, the nature of halo dark matter, the evolution of the stellar halo, new geometric distances, metallicities, masses, and ages of field stars and white dwarfs, and much more. Using the Revised NLTT as an illustrative example, I review the main steps in the assembly of a large catalog of wide binaries useful for multiple applications. The capability of cleanly separating between the Galactic disk and halo populations using good colors and proper motions is emphasized. The critical role of large surveys for research on wide binaries as well as for the better understanding of the Galaxy in general is stressed throughout. Finally, I point out the potential for assembling new samples of wide binaries from available proper-motion surveys, and report on current efforts of using the SDSS towards this goal.

Stellar Archeology: What White Dwarf Stars Tell Us About the History of the Galaxy

“…Newer searches by Pokorny et al (2003), Chanamé & Gould (2004), Lépine & Shara (2005), and Smith et al (2005) identified many new potential fragile binaries in the solar neighborhood. Chanamé (2007) searched the SDSS for nearby fragile pairs in the halo. Zhao et al (2012a) showed that the SDSS contains ultra wide pairs at distances well beyond the solar neighborhood (>1 kpc).…”

Fragile Binaries: Observational Leverage on Difficult Astrophysical Problems

“…Chanamé (2007) is conducting a search of the Sloan Digital Sky Survey to find FBs in the halo. Most will be long-lived low-mass MS+MS pairs whose orbits can set constraints on the dark matter content in the halo (see Chanamé & Gould 2004).…”

“…Silvestri et al (2002) showed that the velocity histograms for the WD+MS sample, look like those of Oppenheimer et al (2001), when degraded by the zero radial velocity assumption necessary for single WDs lacking radial velocity measurements. Recently, Monteiro et al (2006) and Chanamé (2007) have begun looking for FBs of high space velocity. Such pairs will be very important probes of the age and dark matter content in the halo.…”

A distant sample of halo wide binaries from SDSS

“…In consequence, stars in binary systems provide valuable information and influence almost all the branches in astronomy. However, most of this knowledge has come from the study of binary stars in close orbits, while the population of binaries with semi-major axes a 100 AU (often referred to as wide binaries) remains poorly explored, comparatively speaking (Chanamé 2007). Wide binaries have low binding energies and large collisional cross sections, which makes them easily disrupted by any inhomogeneity of the underlying gravitational potential (e.g., passing stars, molecular clouds, spiral arms, etc.)…”