The Binary Fraction of Milky Way Field Stars in DESI: Dependence on Chemical Abundance
Abstract
Binary populations encode information about the physical conditions of star formation and the subsequent evolution of stellar populations. Adopting a statistical method based on multi-epoch line-of-sight velocity variations, we constrain the binary fraction, fb, of field main-sequence turn-off stars in the Milky Way using data from the second data release of the DESI Milky Way Survey. fb is found to primarily increase with lower [Fe/H]. At [Fe/H]≳ −1.3, fb shows a modest increase with increasing [Mg/Fe], whereas no clear trend is detected at lower [Fe/H]. The apparent variations of fb with angular momentum and Galactic height are largely explained by their underlying [Fe/H] distributions, while the remaining variations broadly follow differences in [Mg/Fe]. Within overlapping regions of the [Fe/H]--[Mg/Fe] plane, the thin disk, thick disk, stellar halo and GSE populations exhibit no significant differences in their binary fractions. Thus, our measurements indicate that the variation in fb is dominated by chemical abundance, which could be explained by the metallicity-dependent gas cooling efficiency and fragmentation. The weaker [Mg/Fe] dependence at fixed [Fe/H] might be associated with the formation conditions of stars, with higher [Mg/Fe] stars generally forming earlier under a more gas-rich and turbulent environment.
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BibTeX
@misc{qiu2026binary,
title = {{The Binary Fraction of Milky Way Field Stars in DESI: Dependence on Chemical Abundance}},
author = {Tian Qiu and Wenting Wang and Sergey E Koposov and Songting Li and Nathan Sandford and Ting S Li and Joan Najita and Jessica Nicole Aguilar and Steven Ahlen and Davide Bianchi and David Brooks and Aurelio Carnero Rosell and Todd Claybaugh and Andrei Cuceu and Axel de la Macorra and Arjun Dey and Peter Doel and Jaime E Forero-Romero and Enrique Gaztañaga and Satya Gontcho A. Gontcho and Gaston Gutierrez and Stephanie Juneau and Robert Kehoe and Martin Landriau and Laurent Le Guillou and Aaron Meisner and Ramon Miquel and Enrique Paillas and Will Percival and Francisco Prada and Ignasi Pérez-Ràfols and Corentin Ravoux and Graziano Rossi and Eusebio Sanchez and Christoph Saulder and Edward Schlafly and David Schlegel and Michael Schubnell and Joseph Harry Silber and Małgorzata Siudek and Gregory Tarlé and Benjamin Alan Weaver},
howpublished = {HAL},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.11102},
eprint = {2610.11102},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05841985v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The Binary Fraction of Milky Way Field Stars in DESI: Dependence on Chemical Abundance
AU - Tian Qiu
AU - Wenting Wang
AU - Sergey E Koposov
AU - Songting Li
AU - Nathan Sandford
AU - Ting S Li
AU - Joan Najita
AU - Jessica Nicole Aguilar
AU - Steven Ahlen
AU - Davide Bianchi
AU - David Brooks
AU - Aurelio Carnero Rosell
AU - Todd Claybaugh
AU - Andrei Cuceu
AU - Axel de la Macorra
AU - Arjun Dey
AU - Peter Doel
AU - Jaime E Forero-Romero
AU - Enrique Gaztañaga
AU - Satya Gontcho A. Gontcho
AU - Gaston Gutierrez
AU - Stephanie Juneau
AU - Robert Kehoe
AU - Martin Landriau
AU - Laurent Le Guillou
AU - Aaron Meisner
AU - Ramon Miquel
AU - Enrique Paillas
AU - Will Percival
AU - Francisco Prada
AU - Ignasi Pérez-Ràfols
AU - Corentin Ravoux
AU - Graziano Rossi
AU - Eusebio Sanchez
AU - Christoph Saulder
AU - Edward Schlafly
AU - David Schlegel
AU - Michael Schubnell
AU - Joseph Harry Silber
AU - Małgorzata Siudek
AU - Gregory Tarlé
AU - Benjamin Alan Weaver
PY - 2026
DA - 2026/10/08
PB - HAL
DO - 10.48550/arxiv.2610.11102
UR - https://hal.science/hal-05841985v1
AB - Binary populations encode information about the physical conditions of star formation and the subsequent evolution of stellar populations. Adopting a statistical method based on multi-epoch line-of-sight velocity variations, we constrain the binary fraction, f_b, of field main-sequence turn-off stars in the Milky Way using data from the second data release of the DESI Milky Way Survey. f_b is found to primarily increase with lower [Fe/H]. At [Fe/H]≳ −1.3, f_b shows a modest increase with increasing [Mg/Fe], whereas no clear trend is detected at lower [Fe/H]. The apparent variations of f_b with angular momentum and Galactic height are largely explained by their underlying [Fe/H] distributions, while the remaining variations broadly follow differences in [Mg/Fe]. Within overlapping regions of the [Fe/H]--[Mg/Fe] plane, the thin disk, thick disk, stellar halo and GSE populations exhibit no significant differences in their binary fractions. Thus, our measurements indicate that the variation in f_b is dominated by chemical abundance, which could be explained by the metallicity-dependent gas cooling efficiency and fragmentation. The weaker [Mg/Fe] dependence at fixed [Fe/H] might be associated with the formation conditions of stars, with higher [Mg/Fe] stars generally forming earlier under a more gas-rich and turbulent environment.
ER -