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arXiv 2402.18538astro-ph.GA
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利用红团簇星对疏散星团进行年龄校准的研究

On the Age Calibration of Open Clusters using Red Clump Stars

Abigail R. Chriss, Guy Worthey

AI总结:

本文利用Gaia DR3数据研究疏散星团中红巨星支与红团簇的颜色差随年龄的变化,发现该关系在年轻星团中变为双值且与金属丰度无关,指出现有恒星演化模型无法重现观测趋势。

摘要:

在本研究中,我们将Hatzidimitriou(1991)提出的、与尘埃无关的星团年龄与红巨星支(RGB)和红团簇之间$d_{B-R}$颜色差的关系扩展到更年轻的星团年龄。我们利用Gaia DR3天体测量数据对十四个银河系疏散星团进行了成员星分析,然后利用Gaia测光数据计算了红巨星支与红团簇的颜色差$d_{B-R}$。我们还计算了小麦哲伦云(SMC)星团周围五个天区的$d_{B-R}$。我们发现,从较年长星团推导出的趋势并不能外推到较年轻的年龄,并且该关系变为双值。我们确认$d_{B-R}$与金属丰度无关。当前的恒星演化等龄线无法定量地重现这一趋势,并且进一步预测颜色间隙会随着金属丰度的降低而增大,但数据中并未体现这一现象。基于当前等龄线的集成光模型在$-0.5 <$ [Fe/H] $< 0$区间内以百分之几的水平夸大了颜色变化。

英文摘要:

In this study, we extend the dust-independent Hatzidimitriou (1991) relation between cluster age and $d_{B-R}$ color difference between the red giant branch (RGB) and red clump to younger cluster ages. We perform membership analysis on fourteen galactic open clusters using Gaia DR3 astrometry, then compute the difference in color of the RGB and red clump $d_{B-R}$ using Gaia photometry. We also compute $d_{B-R}$ for five fields surrounding Small Magellanic Cloud (SMC) clusters. We find that the trend derived from older clusters does not extrapolate to younger ages and becomes double-valued. We confirm that $d_{B-R}$ is independent of metallicity. Current stellar evolutionary isochrones do not quantitatively reproduce the trend and furthermore predict an increased color gap with a decrease in metallicity that is not echoed in the data. Integrated light models based on current isochrones exaggerate the color change over the $-0.5 <$ [Fe/H] $< 0$ interval at the few-percent level.

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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