AI 中文总结
本研究基于盖亚 DR3 数据，分析 500 pc 内 301 颗热亚矮星的短周期双星族，得出其短周期双星占比、新发现多类双星系统，并估算相关并合率与 SN Ia 前身星贡献。
AI 中文摘要
双星中光谱型为 O 型和 B 型的热亚矮星（sdO/B）是红巨星支顶端附近发生大量质量损失的产物，能为双星演化模型提供有力约束，但部分形成通道的细节仍未明确。我们利用盖亚 DR3 的精确视差，对 500 pc 限体积热亚矮星样本中的短周期双星族开展了全面分析。除了 500 pc 范围内已知的 45 个双星系统，本研究还新发现 50 个单谱线视向速度变源系统，其中 34 个拥有轨道解，周期介于 0.07 至 22 天之间。针对 500 pc 范围内全部 301 颗热亚矮星样本，我们校正轨道倾角和探测效率后，得出短周期双星占比为 34.7（+2.8/-2.9）%。新解出的双星系统主要分布在 1-20 天的周期范围内，该参数空间此前在文献中记录较少。我们识别出 5 个新的反射效应系统、3 个椭球调制系统、1 个新解出的 HW Vir 系统以及 1 个新的三星候选体。sdB 型和 sdO 型热亚矮星的双星占比相近，而 sdOB 型的占比约为 sdB/sdO 型的一半，且周期均超过 1 天，表明其演化路径存在差异。低于经典极端水平分支的低光度热亚矮星，其双星占比与其他 sdB/sdO 型热亚矮星相当，但仅拥有白矮星伴星，这些伴星质量更大，且主要分布在周期短于 1 天的系统中。我们提供了亚族的首个体积完整的出生率估算，得出 sdO/B 型双星的银河系并合率为 2.5±1.5×10⁻⁵ 年⁻¹，解释的 eHe-sdO 族数量不超过 12%。我们还得出了两种 Ia 型超新星（SN Ia）前身星通道的出生率，发现热亚矮星双星可解释观测到的银河系 SN Ia 率的 2.5（+0.7/-0.5）%。
英文摘要
Hot subdwarf stars of spectral types O and B (sdO/B) in binaries form as products of substantial mass loss near the tip of the red giant branch and offer powerful constraints on binary-star evolutionary models. However, details of some formation channels remain missing. We present a comprehensive analysis of the short-period binary population in the 500 pc volume-limited sample of hot subdwarfs, enabled by precise Gaia DR3 parallaxes. Besides 45 known binaries within 500 pc, this work identifies 50 new single-lined radial-velocity variable systems, 34 with orbital solutions with periods between 0.07 and 22 days. We derive an overall short-period binary fraction of 34.7 (+2.8/-2.9)% for the full sample of 301 hot subdwarfs within 500 pc, corrected for orbital inclination and detection efficiency. The newly solved binaries predominantly occupy the 1-20 day range, a parameter space previously under-represented in the literature. We identify five new reflection-effect systems, three ellipsoidal modulation systems, a newly solved HW Vir system, and a new triple candidate. The sdB and sdO binary fractions are similar, while the sdOB class shows a fraction roughly half that of sdB/sdO stars, with periods over one day, suggesting a different evolutionary pathway. Underluminous hot subdwarfs below the canonical extreme horizontal branch show a binary fraction comparable to other sdB/sdO stars but host only white dwarf companions, which are more massive and mainly found at periods under one day. We provide the first volume-complete birthrate estimates for sub-populations, determining a Galactic merger rate of 2.5+-1.5x10^-5 yr^-1 for sdO/B binaries, explaining no more than ~12% of the eHe-sdO population. We also derive birthrates for two SN Ia progenitor channels, finding hot subdwarf binaries could account for up to 2.5 (+0.7/-0.5)% of the observed Galactic SN Ia rate.
Comments24 pages, 13 figures, accepted in A&A
