arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新，休息一下吧，周末愉快~~
arXiv 1606.01181astro-ph.SR
收藏

RR型天琴座星inM5长期周期变化的新研究

A New Overview of Secular Period Changes of RR Lyrae stars inM5

A. Arellano Ferro, J. A. Ahumada, N. Kains, A. Luna

备注：
Accepted in MNRAS, June 3, 2016; 13 pages 3 tables 5 figures
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

利用我们最新的CCD $V$测光和1889年以来文献中的历史测光数据库，分析了球状星团M5中76颗天琴座RR型星的长期周期变化$β=\dot{P}$。这为这些变量提供了长达118年的时间基线。使用两种独立的方法进行分析：第一，经典的$O-C$行为的时间最大的光，第二，通过网格$(P,β)$，其中的解决方案产生的最小散射的相位光变曲线被选择。两种方法的结果令人满意地一致。这使得对M5中许多天琴座RR型恒星周期变化的性质有了新的解释。结果发现，在所研究的恒星的$96\%$没有不规则或随机变化需要索赔，但人口的$66\%$显示稳定的周期增加或减少，和周期的$34\%$似乎一直稳定在过去的世纪。缺乏系统的积极或消极的周期变化的RR天琴座恒星在其他球状星团的解决，和作为恒星演化的结果周期变化的范例进行了讨论，在恒星核心附近的化学变化和多个恒星种群。在M5中，我们发现了一个小的正平均值的$β$和一个小的盈余RRab星的周期增加。尽管如此，在M5中，我们已经能够分离出一组可能进化的恒星，它们系统地显示出正的（在某些情况下是很大的）周期变化率。

英文摘要：

Secular period variations, $β=\dot{P}$, in 76 RR Lyrae stars in the globular cluster M5 are analysed using our most recent CCD $V$ photometry and the historical photometric database available in the literature since 1889. This provides a time baseline of up to 118 years for these variables. The analysis was performed using two independent approaches: first, the classical $O-C$ behaviour of the time of maximum light, and second, via a grid $(P,β)$, where the solution producing the minimum scatter in the phased light curve is chosen. The results of the two methods agree satisfactorily. This allowed a new interpretation of the nature of the period changes in many RR Lyrae stars in M5. It is found that in $96\%$ of the stars studied no irregular or stochastic variations need to be claimed, but that $66\%$ of the population shows steady period increases or decreases, and that $34\%$ of the periods seem to have been stable over the last century. The lack of systematic positive or negative period variations in RR Lyrae stars in other globular clusters is addressed, and the paradigm of period changes being a consequence of stellar evolution is discussed in terms of chemical variations near the stellar core and of multiple stellar populations. In M5 we found a small positive average value of $β$ and a small surplus of RRab stars with a period increase. Nevertheless, in M5 we have been able to isolate a group of likely evolved stars that systematically show positive, and in some cases large, period change rates.

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。

↑