Year: 2026
Type: preprint
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, $f_b$, 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 $[\mathrm{Fe}/\mathrm{H}]\gtrsim -1.3$, $f_b$ 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.
Source: arXiv (Cornell University)
Authors: Qiu, Tian, Wang, Wenting, Koposov, Sergey E., Li, Songting, Sandford, Nathan, Li, Ting S., Najita, Joan, Aguilar, Jessica Nicole, Ahlen, Steven, Bianchi, Davide, Brooks, David, Rosell, Aurelio Carnero, Claybaugh, Todd, Cuceu, Andrei, de la Macorra, Axel, Dey, Arjun, Doel, Peter, Forero-Romero, Jaime E., Gaztañaga, Enrique, Gontcho, Satya Gontcho A, Gutierrez, Gaston, Juneau, Stephanie, Kehoe, Robert, Landriau, Martin, Guillou, Laurent Le, Meisner, Aaron, Miquel, Ramon, Paillas, Enrique, Percival, Will, Prada, Francisco, Pérez-Ràfols, Ignasi, Ravoux, Corentin, Rossi, Graziano, Sanchez, Eusebio, Saulder, Christoph, Schlafly, Edward, Schlegel, David, Schubnell, Michael, Silber, Joseph Harry, Siudek, Małgorzata, Tarlé, Gregory, Weaver, Benjamin Alan
Institutions: Shanghai Jiao Tong University, Shanghai Key Laboratory for Particle Physics and Cosmology, University of Cambridge, Royal Observatory, University of Edinburgh, University of Toronto, NSF NOIRLab, Lawrence Berkeley National Laboratory, Boston University, University of Milan, Brera Astronomical Observatory, University College London, Universidad de La Laguna, Instituto de Astrofísica de Canarias, Universidad Nacional Autónoma de México, Universidad de Los Andes, Institut d'Estudis Espacials de Catalunya, University of Portsmouth, Universitat Politècnica de Catalunya, Fermi National Accelerator Laboratory, Southern Methodist University, Institució Catalana de Recerca i Estudis Avançats, Institute for High Energy Physics, Barcelona Institute of Science and Technology, Universidad Diego Portales, Centre National de la Recherche Scientifique, Consejo Superior de Investigaciones Científicas, University of Waterloo, Perimeter Institute, Université Clermont Auvergne, Sejong University, Max Planck Institute for Extraterrestrial Physics, Instituto de Astrofísica de Andalucía, Universidad Autónoma de Madrid
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, Gordon and Betty Moore Foundation, Ministerio de Ciencia, Innovación y Universidades, National Energy Research Scientific Computing Center, European Space Agency, National Natural Science Foundation of China, Shanghai Jiao Tong University, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Office of Science, Science and Technology Facilities Council, Agencia Estatal de Investigación, Division of Astronomical Sciences
Awards: G1044631029, G1105844351, G122673668, G1286236842, G1677143136, G1813527838, G1863003419, G1864818996, G2461805613, G3452655474, G3582141642, G419881185, G42916606, G4501827968, G491712853, G498139845, G5076365615, G5635532810, G593054264, G6190274306, G6209684921, G6652958823, G6876926712, Probing dark matter distribution in the Milky Way with the DESI survey, G704498496, Management and Operations of the National Optical Astronomy Observatory, G7395345766, G7805626310, G7863371703, G8497050386, G8667377315, G9000046764
OpenAlex ID: W7221079719