Not that simple: the metallicity dependence of the wide binary fraction changes with separation and stellar mass
arXiv:2205.04444 · doi:10.3847/1538-4357/ac6c84
Abstract
The metallicity dependence of the wide binary fraction (WBF) is critical for studying the formation of wide binaries. While controversial results have been found in recent years. Here we combine the wide binary catalog recognized from Gaia EDR3 and stellar parameters from LAMOST to investigate this topic. Taking bias of the stellar temperature at given separations into account, we find that the relationship between the WBF and metallicity depends on temperature for the thin-disk at s > 200 AU. It changes from negative to positive as the temperature increases from 4000 K to 7500 K. This temperature/mass dependence is not seen for the thick-disk. Besides, the general tendency between the WBF and metallicity varies with the separation, consistent with previous results. It shows anti-correlation at small separations, s < 200 AU for the thin-disk and s < 600 AU for the thick-disk. Then it becomes an "arcuate" shape at larger separations (hundreds to thousands of AU), peaking at [Fe/H] ~ 0.1 for the thin-disk and [Fe/H] ~ -0.5 for the thick disk. Finally it becomes roughly flat for the thin-disk at 1000 < s < 10000 AU. Our work provides new observational evidences for theoretical studies on binary formation and evolution.
14 pages, 9 figures, ApJ accepted. Comments are welcome
References in corpus (13)
- The Gaia mission
- A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties
- New Distant Companions to Known Nearby Stars. II. Faint companions of Hipparcos stars and the frequency of wide binary systems
- LAMOST Spectroscopic Survey of the Galactic Anti-centre (LSS-GAC): target selection and the first release of value-added catalogues
- A catalog of wide binary and multiple systems of bright stars from Gaia-DR2 and the Virtual Observatory
- Stellar loci II. a model-free estimate of the binary fraction for field FGK stars
- The stellar velocity distribution function in the Milky Way galaxy
- The Metallicity of Stars with Close Companions
- Effects of the selection function on metallicity trends in spectroscopic surveys of the Milky Way
- Binary fractions of G and K dwarf stars based on the Gaia EDR3 and LAMOST DR5: impacts of the chemical abundances
- Kinematics of the Galactic disk from LAMOST Dwarf sample
- Wide binaries from the H3 survey: the thick disk and halo have similar wide binary fractions
- Atomic diffusion in solar-like stars with MESA. Comparison with the Montreal/Montpellier and CESTAM stellar evolution codes