Extended Main-sequence Turnoffs in the Double Cluster h and χ Persei: The Complex Role of Stellar Rotation

doi:10.3847/1538-4357/ab15d2

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	Extended Main-sequence Turnoffs in the Double Cluster h and χ Persei: The Complex Role of Stellar Rotation
	Li,Chengyuan 7,8,9; Sun,Weijia 5,6; Grijs,Richard de 4,8,9; Deng,Licai 3,7; Wang,Kun 2,3; Cordoni,Giacomo 1; Milone,Antonino P.1
刊名	The Astrophysical Journal
	2019-05-06
卷号	876 期号:1
关键词	Hertzsprung–Russell and C–M diagrams open clusters and associations: individual (NGC 869 and NGC 884)
ISSN号	0004-637X
DOI	10.3847/1538-4357/ab15d2
英文摘要	Abstract Using Gaia Data Release 2 photometry, we report the detection of extended main-sequence turnoff (eMSTO) regions in the color–magnitude diagrams (CMDs) of the ～14 Myr old double clusters h and χ Persei (NGC 869 and NGC 884). We find that stars with masses below ～1.3 M⊙ in both h and χ Persei populate narrow main sequences (MSs), while more massive stars define the eMSTO, closely mimicking observations of young Galactic and Magellanic Cloud clusters (with ages older than ～30 Myr). Previous studies based on clusters older than ～30 Myr found that rapidly rotating MS stars are redder than slow rotators of similar luminosity, suggesting that stellar rotation may be the main driver of the eMSTO. By combining photometry and projected rotational velocities from the literature of stars in h and χ Persei, we find no obvious relation between the rotational velocities and colors of non-emission-line eMSTO stars, in contrast with what is observed in older clusters. Similar to what is observed in Magellanic Cloud clusters, most of the extremely rapidly rotating stars, identified by their strong Hα emission lines, are located in the red part of the eMSTOs. This indicates that stellar rotation plays a role in the color and magnitude distribution of MSTO stars. By comparing the observations with simulated CMDs, we find that a simple population composed of coeval stars that span a wide range of rotation rates is unable to reproduce the color spread of the cluster’s MSs. We suggest that variable stars, binary interactions, and stellar rotation affect the eMSTO morphology of these very young clusters.
语种	英语
出版者	The American Astronomical Society
WOS记录号	IOP:0004-637X-876-1-AB15D2
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/28872]
专题	中国科学院国家天文台
作者单位	1.Dipartimento di Fisica e Astronomia “Galileo Galilei,” Università di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova, Italy 2.Instituto de Astrof?isica de Canarias, E-38200 La Laguna, Tenerife, Spain 3.Department of Astronomy, China West Normal University, Nanchong 637002, People’s Republic of China 4.International Space Science Institute–Beijing, 1 Nanertiao, Zhongguancun, Hai Dian District, Beijing 100190, People’s Republic of China 5.Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Lu 5, Hai Dian District, Beijing 100871, People’s Republic of China 6.Department of Astronomy, Peking University, Yi He Yuan Lu 5, Hai Dian District, Beijing 100871, People’s Republic of China 7.Key Laboratory for Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Beijing 100012, People’s Republic of China 8.Centre for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109, Australia 9.Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109, Australia; chengyuan.li@mq.edu.au
推荐引用方式 GB/T 7714	Li,Chengyuan,Sun,Weijia,Grijs,Richard de,et al. Extended Main-sequence Turnoffs in the Double Cluster h and χ Persei: The Complex Role of Stellar Rotation[J]. The Astrophysical Journal,2019,876(1).
APA	Li,Chengyuan.,Sun,Weijia.,Grijs,Richard de.,Deng,Licai.,Wang,Kun.,...&Milone,Antonino P..(2019).Extended Main-sequence Turnoffs in the Double Cluster h and χ Persei: The Complex Role of Stellar Rotation.The Astrophysical Journal,876(1).
MLA	Li,Chengyuan,et al."Extended Main-sequence Turnoffs in the Double Cluster h and χ Persei: The Complex Role of Stellar Rotation".The Astrophysical Journal 876.1(2019).