发表机构
Konkoly Observatory, HUN-REN CSFK; CSFK, MTA Centre of Excellence; Eötvös Loránd University, Institute of Physics and Astronomy; The Ohio State University; Center for Cosmology and Astroparticle Physics (CCAPP), The Ohio State University; Princeton University（孔科利天文台，匈牙利研究与教育网络科学中心; 匈牙利科学院卓越研究中心; 厄特沃什·罗兰大学物理与天文学研究所; 俄亥俄州立大学; 俄亥俄州立大学宇宙学与高能粒子物理中心; 普林斯顿大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究对K2观测的极贫金属球状星团NGC 5897的20颗RGB、6颗EAGB恒星开展星震学分析，推导其质量与总质量损失，更新I型球状星团质量损失-金属丰度关系，支持RGB总质量损失随金属丰度降低而减小的结论。
AI 中文摘要
低质量恒星在红巨星支（RGB）和早渐近巨星支（EAGB）阶段的质量损失对恒星演化至关重要，但其对金属丰度等恒星参数的依赖关系仍未明确，观测研究得出的趋势相互矛盾。我们对K2任务期间开普勒空间望远镜观测到的最遥远、最贫金属球状星团NGC 5897中的RGB和EAGB恒星开展了首次星震学分析。我们探测到20颗RGB恒星和6颗EAGB恒星的类太阳振荡，并推导得到最大功率过剩频率ν_max。利用星震学标度关系，我们得出RGB恒星平均质量为$\bar{M}_{RGB}=0.74\boldsymbol{\u00B1}0.01M_\u2609$，EAGB恒星平均质量为$\bar{M}_{EAGB}=0.65\boldsymbol{\u00B1}0.03M_\u2609$。两个阶段间的总质量损失推导为$\boldsymbol{\u0394}M_{RGB-EAGB}=0.08\boldsymbol{\u00B1}0.03M_\u2609$。我们提出了I型球状星团更新后的质量损失-金属丰度关系，将其扩展至极贫金属区域，支持RGB总质量损失随金属丰度降低而减小的结论。
英文摘要
Mass loss in low-mass stars during the red giant branch (RGB) and early asymptotic giant branch (EAGB) phases plays a key role in shaping stellar evolution, yet its dependence on stellar parameters such as metallicity remains poorly constrained, with observational studies yielding conflicting trends. We present the first asteroseismic analysis of RGB and EAGB stars in NGC 5897, the most distant and metal-poor globular cluster observed by the Kepler space telescope during the K2 mission. We detected solar-like oscillations and derived the frequency of maximum power excess, $ν_{\rm max}$, for 20 RGB and 6 EAGB stars. Using asteroseismic scaling relations, we derived mean masses of $\overline{M}_{\rm RGB} = 0.74\pm0.01\,M_{\odot}$ and $\overline{M}_{\rm EAGB}=0.65\pm 0.03\,M_{\odot}$. The inferred integrated mass loss between the two phases is $ΔM_{\rm RGB-EAGB}=0.08\pm 0.03 \,M_{\odot}$. We present an updated mass-loss--metallicity relation for Type I globular clusters, extending it to the very metal-poor regime and supporting decreasing integrated RGB mass loss with decreasing metallicity.
CommentsAccepted for publication in ApJL, 16 pages, 10 figures, 2 tables
