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arXiv 2602.00896astro-ph.SR
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γ Persei 双星系统的蓝离散星并合起源

A blue-straggler merger scenario origin for the $γ$~Persei binary system

Konkoly Observatory, HUN-REN CSFK（孔科利天文台，匈牙利研究网络学术卓越中心）；MTA Centre of Excellence（匈牙利科学院卓越中心）；ELTE Eötvös Loránd University（罗兰大学）

D. Tarczay-Nehéz, L. Molnár, R. Z. Ádám

备注：
accepted to A&A
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AI总结：

通过等时线拟合和恒星演化模型，发现γ Persei双星无法用标准双星演化解释，提出其主星由三体系统中的一对主序星并合形成，并限定了并合时间与质量范围。

摘要：

我们使用 \texttt{MIST} 等时线拟合和用 MESA 计算的一组专用恒星演化模型来约束 $\gamma$ Persei 双星系统各分量的年龄。虽然单个恒星可以在特定金属丰度下与模型匹配，但没有联合等时线解能同时再现观测到的质量和演化状态。MESA 计算的恒星演化轨迹揭示了明显的演化不匹配。系统的主星处于与红巨星支或红团簇一致的主序后阶段。相比之下，较轻的次星位于主序转折点附近或处于亚巨星支的早期阶段。这种差异可以通过假设 $\gamma$ Persei 系统诞生时为三合星且主星是通过一对靠近的主序星并合形成的返老还童星来克服。我们表明，并合必须发生在系统形成后不超过几亿年内，且并合恒星的前身星质量受限于 $(M_{1,a},M_{1,b})$ 平面中一条窄带内的恒星组合，对应 $M_{1,a}\simeq0.9$--$2.1\\,M_\odot$ 和 $M_{1,b}\simeq2.3$--$2.5\\,M_\odot$。

英文摘要：

We used \texttt{MIST} isochrone fitting and a dedicated grid of stellar evolution models computed with MESA to constrain the ages of the components of the $γ$ Persei binary system. While individual stars can be matched to the models at specific metallicities, no joint isochrone solution reproduces both the observed masses and evolutionary states. The stellar evolutionary tracks calculated by MESA reveal a clear evolutionary mismatch. The primary component of the system is in a post-main-sequence phase consistent with the red giant branch or red clump. In contrast, the lighter secondary component lies near the turn-off point of the main sequence or is in the early phase of the subgiant branch. This discrepancy can be overcome by assuming that the $γ$ Persei system was born as a triple and the primary component is a rejuvenated star formed through a merger of a close-by pair of main-sequence stars. We show that the merger must have occurred no later than a few hundred megaryears after system formation, and the progenitor masses of the merging stars are restricted by a combination of stars that fall within a narrow band in the $(M_{1,a},M_{1,b})$ plane, corresponding to $M_{1,a}\simeq0.9$--$2.1\,M_\odot$ and $M_{1,b}\simeq2.3$--$2.5\,M_\odot$.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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