盖亚天体测量揭示的低质量恒星中与质量相关的多重性比例
Mass-dependent multiplicity fraction in low mass stars revealed by Gaia astrometry
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中文总结 AI 辅助
利用盖亚DR3天体测量数据，开发正向建模框架分析36.6万颗0.2-0.75倍太阳质量恒星，发现其多重性比例随质量变化，修正了传统单调上升的质量-多重性关系。
中文摘要 AI 辅助
不同轨道周期的恒星多重性可通过不同技术探测：最短周期用视向速度，最长周期用直接成像，中间周期用天体测量。盖亚DR3提供了前所未有的天体测量信息，可约束周期为数十至数千天的双星族群。除了少量直接轨道解外，盖亚还为所有天体发布了更粗略的天体测量诊断量，如天球加速度、加加速度或单星拟合优度指标RUWE。我们表明，这些诊断量结合起来对轨道周期的敏感范围远大于仅用轨道解的情况。基于Gaiamock模拟器，我们开发了正向建模框架，利用所有天体测量解类型从盖亚数据中约束多重性比例。我们将该框架应用于距离50至200秒差距、质量0.2至0.75倍太阳质量的366027颗主星，包含的M型矮星数量远超以往多重性研究。对于周期和质量比分布的基准模型，推断出的多重性比例从类太阳恒星区域降至0.4倍太阳质量时大致保持在约45%，之后降至0.2倍太阳质量时的约15%。这种质量-多重性关系修正了传统的单调上升的质量-多重性关系图像，使M型矮星的质量上限区域与类太阳恒星一致，而非处于持续下降的序列中。
英文摘要
Stellar multiplicity at different orbital periods is probed by different techniques: radial velocities at the shortest periods, direct imaging at the longest, and astrometry in between. Gaia DR3 provides unprecedented astrometric information to constrain binary populations with periods of tens to thousands of days. Beyond the small fraction of direct orbit solutions, Gaia publishes coarser astrometric diagnostics for all objects, such as on-sky accelerations, jerks, or the single-star goodness-of-fit measure, RUWE. We show that these diagnostics together are sensitive to a far wider range of orbital periods than orbit solutions alone. Built on the Gaiamock emulator, we develop a forward-modelling framework to constrain rates of multiplicity from Gaia data, using all astrometric solution types. We apply this framework to $366~027$ primaries of $0.2$--$0.75\,M_\odot$ between $50$ and $200$ pc, including vastly more M-dwarfs than previous multiplicity studies. For fiducial models of the period and mass-ratio distributions, the inferred multiplicity fraction is approximately constant at ${\sim}45\%$ from the solar-type regime down to $0.4\,M_\odot$, only then dropping to ${\sim}15\%$ by $0.2\,M_\odot$. This mass-multiplicity relationship revises the conventional picture of a monotonically rising mass--multiplicity relation, and aligns the upper M-dwarf regime with solar-type stars rather than placing it on a continuous decline.
发表机构
- Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）
- Fakultät für Physik und Astronomie, Universität Heidelberg（海德堡大学物理与天文学院）
- Department of Astronomy, California Institute of Technology（加州理工学院天文学系）
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