IACOB项目 XVIII：银晕富氦O型星中短周期双星的普遍性
The IACOB project XVIII. Prevalence of short-period binaries among Galactic helium rich O-type stars
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中文总结 AI 辅助
IACOB项目研究45个O型SB1系统发现7个短周期富氦O型星，证实双星相互作用是其氦富集的主导起源，对大质量恒星演化模型及后相互作用双星识别有重要意义。
中文摘要 AI 辅助
数十年来，O型星氦丰度的起源一直是个悬而未决的问题。本研究对包含Cyg X-1在内的45个O型SB1系统样本，探究了表面氦丰度与轨道参数的关联。研究共发现7个富氦系统，全部集中在短轨道周期（P≲15天）且均为逃兵星；其中4个具有相对较高的偏心率，另外3个存在椭球变光。研究认为这些特性是双星相互作用的结果，为双星相互作用是O型星氦富集的主导起源提供了有力观测证据，该结果对大质量恒星演化模型中化学混合与表面丰度的处理具有重要意义，且确立了氦富集作为识别后相互作用双星系统的有效观测示踪剂的潜力。
英文摘要
For decades, the origin of helium enrichment in O-type stars has remained an open question. In this study, we investigate the correlation between surface helium abundance and orbital parameters for a sample of 45 O-type SB1 systems --including Cyg X-1. We find seven He-rich systems, all of which are concentrated at short orbital periods (P$\lesssim 15$ days) and are classified as runaways. In addition, four of them present relatively high eccentricities, while the other three have ellipsoidal variations. We argue that these properties are the result of binary interaction. These findings provide strong observational evidence that binary interaction is the dominant origin of helium enrichment in O-type stars. This result has important implications for the treatment of chemical mixing and surface abundances in massive-star evolutionary models, and establishes helium enrichment as a promising observational tracer for identifying post-interaction binary systems.
