Stellar Parameters and Orbital Period Estimates for Composite-Spectrum sdB+MS Binaries from LAMOST

Fuente: arXiv
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Autores principales: Li, Jiangdan, Xiong, Jianping, Li, Jiao, Chen, Hai-Liang, Ge, Hongwei, Yang, Mingkuan, Chen, Xuefei, Han, Zhanwen
Formato: Preprint
Publicado: 2026
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author Li, Jiangdan
Xiong, Jianping
Li, Jiao
Chen, Hai-Liang
Ge, Hongwei
Yang, Mingkuan
Chen, Xuefei
Han, Zhanwen
author_facet Li, Jiangdan
Xiong, Jianping
Li, Jiao
Chen, Hai-Liang
Ge, Hongwei
Yang, Mingkuan
Chen, Xuefei
Han, Zhanwen
contents Hot subdwarf (sdB) stars in binary systems with main-sequence (MS) companions provide valuable insights into mass transfer and envelope ejection processes in binary evolution. Their mass ratios, orbital periods, and stellar properties encode key information about their evolutionary histories. In this work, we analyze a sample of 123 composite-spectrum sdB+MS binaries identified from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope Low-Resolution Survey (LAMOST-LRS) Data Release (DR) 8. We adopt atmospheric parameters from spectral decomposition and estimate stellar masses and radii using theoretical evolutionary tracks. Radial velocities for both the hot subdwarfs and cool companions are measured independently through cross-correlation with synthetic templates. Orbital periods are statistically estimated using single-epoch RV separations and a Monte Carlo method that accounts for random inclination and orbital phase. We find that sdB masses are narrowly distributed around 0.5 Msun, consistent with expectations for core helium-burning stars, while MS companion masses span 0.6-1.9 Msun, with most falling between 1.0 and 1.4 Msun. The inferred orbital-period distribution shows a clear concentration toward long periods, broadly consistent with expectations for binaries formed through stable Roche-lobe overflow. Given that our sample consists of composite-spectrum sdB binaries, mainly sdB+FGK systems, the prevalence of long periods is largely driven by observational selection effects rather than the intrinsic period distribution of the sdB binary population. This study provides one of the largest uniform catalogs of composite spectrum sdB binaries to date, offering new observational constraints on their physical properties and formation channels.
format Preprint
id arxiv_https___arxiv_org_abs_2604_04110
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Stellar Parameters and Orbital Period Estimates for Composite-Spectrum sdB+MS Binaries from LAMOST
Li, Jiangdan
Xiong, Jianping
Li, Jiao
Chen, Hai-Liang
Ge, Hongwei
Yang, Mingkuan
Chen, Xuefei
Han, Zhanwen
Solar and Stellar Astrophysics
Hot subdwarf (sdB) stars in binary systems with main-sequence (MS) companions provide valuable insights into mass transfer and envelope ejection processes in binary evolution. Their mass ratios, orbital periods, and stellar properties encode key information about their evolutionary histories. In this work, we analyze a sample of 123 composite-spectrum sdB+MS binaries identified from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope Low-Resolution Survey (LAMOST-LRS) Data Release (DR) 8. We adopt atmospheric parameters from spectral decomposition and estimate stellar masses and radii using theoretical evolutionary tracks. Radial velocities for both the hot subdwarfs and cool companions are measured independently through cross-correlation with synthetic templates. Orbital periods are statistically estimated using single-epoch RV separations and a Monte Carlo method that accounts for random inclination and orbital phase. We find that sdB masses are narrowly distributed around 0.5 Msun, consistent with expectations for core helium-burning stars, while MS companion masses span 0.6-1.9 Msun, with most falling between 1.0 and 1.4 Msun. The inferred orbital-period distribution shows a clear concentration toward long periods, broadly consistent with expectations for binaries formed through stable Roche-lobe overflow. Given that our sample consists of composite-spectrum sdB binaries, mainly sdB+FGK systems, the prevalence of long periods is largely driven by observational selection effects rather than the intrinsic period distribution of the sdB binary population. This study provides one of the largest uniform catalogs of composite spectrum sdB binaries to date, offering new observational constraints on their physical properties and formation channels.
title Stellar Parameters and Orbital Period Estimates for Composite-Spectrum sdB+MS Binaries from LAMOST
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2604.04110