Magnetic activity and age estimation of red giants using neural networks

doi:10.1093/mnras/stab1395

	Magnetic activity and age estimation of red giants using neural networks
	Lu, Hong-peng 1,2,3; Karoff, Christoffer 3,4; Zhang, Li-yun 1,2,5
发表期刊	MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
	2021-06-08
卷号	505 期号:2 页码:2124-2135
DOI	10.1093/mnras/stab1395
收录类别	SCI
关键词	methods: data analysis stars: activity stars: evolution stars: fundamental parameters
摘要	In this work, we analysed the magnetic activity of 5349 Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) low-dispersion spectra of 3539 red giants by calculating equivalent width (EW) of magnetic activity lines (H alpha, H beta, H gamma, H delta, Ca II H&K, Ca II IRT). Combining LAMOST spectral parameters, asteroseismic parameters, and EWs of the magnetic activity lines, an attempt was made to estimate the age of red giants using neural networks. By using the neural networks to select the input parameters, we get the best age estimation of the red giants with the input parameters 'T-eff', '[Fe/H]', 'log g', 'nu(max)', and 'Delta nu', which is in line with expectations. The average value of the relative error between the estimated age and the isochronous age is 22.4 per cent. The age estimation was not improved by adding the EWs of more magnetic activity lines. This indicates that the EWs of these spectral lines are not directly related to the age of the red giants. The reason for this might be that the dynamo operating in the outer layers of the red giants has shut off at the end of core-hydrogen-burning. The absence of emission in all the magnetic activity lines of the 5349 LAMOST spectra also confirms this conclusion. In addition, the results indicate that the EWs of the magnetic activity lines are more related to the effective temperature, which is also in line with expectations.
资助项目	National Development and Reform Commission ; China Scholarship Fund ; NSFC[11963002] ; NSFC[U1631236] ; NSFC[U1431114] ; CAS[11963002] ; CAS[U1631236] ; CAS[U1431114] ; Open Project Program of the Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences
项目资助者	National Development and Reform Commission ; China Scholarship Fund ; NSFC[11963002, U1631236, U1431114] ; CAS[11963002, U1631236, U1431114] ; Open Project Program of the Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences
语种	英语
学科领域	天文学 ; 恒星与银河系 ; 恒星形成与演化
文章类型	Article
出版者	OXFORD UNIV PRESS
出版地	GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND
ISSN	0035-8711
URL	查看原文
WOS记录号	WOS:000767895100009
WOS研究方向	Astronomy & Astrophysics
WOS类目	Astronomy & Astrophysics
关键词[WOS]	DIGITAL SKY SURVEY ; ACTIVITY-ROTATION RELATIONSHIP ; SOLAR-LIKE OSCILLATIONS ; X-RAY-EMISSION ; CHROMOSPHERIC ACTIVITY ; LAMOST OBSERVATIONS ; STELLAR ACTIVITY ; APOKASC CATALOG ; ISOCHRONE AGES ; COOL STARS
引用统计
文献类型	期刊论文
条目标识符	http://ir.ynao.ac.cn/handle/114a53/24514
专题	中国科学院天体结构与演化重点实验室
通讯作者	Karoff, Christoffer; Zhang, Li-yun
作者单位	1.Guizhou Univ, Coll Phys, Guiyang 550025, Peoples R China 2.Guizhou Univ, Guizhou Prov Key Lab Publ Big Data, Guiyang 550025, Peoples R China 3.Aarhus Univ, Stellar Astrophys Ctr, Dept Phys & Astron, Ny Munkegade 120, DK-8000 Aarhus C, Denmark 4.Aarhus Univ, Dept Geosci, Hoegh Guldbergs Gade 2, DK-8000 Aarhus C, Denmark 5.Chinese Acad Sci, Key Lab Struct & Evolut Celestial Objects, Kunming 650011, Yunnan, Peoples R China
推荐引用方式 GB/T 7714	Lu, Hong-peng,Karoff, Christoffer,Zhang, Li-yun. Magnetic activity and age estimation of red giants using neural networks[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2021,505(2):2124-2135.
APA	Lu, Hong-peng,Karoff, Christoffer,&Zhang, Li-yun.(2021).Magnetic activity and age estimation of red giants using neural networks.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,505(2),2124-2135.
MLA	Lu, Hong-peng,et al."Magnetic activity and age estimation of red giants using neural networks".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 505.2(2021):2124-2135.

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