LAMOST低分辨率光谱中A型星的恒星参数测量新方法  

A New Method for Measuring Stellar Parameters of A-Type Stars in LAMOST Low-Resolution Spectra

作　　者：左芳 罗阿理[1,2] ZUO Fang;LUO Ali(Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院国家天文台光学天文重点实验室,北京100101 [2]中国科学院大学,北京100049

出　　处：《天文学进展》2024年第4期618-627,共10页Progress In Astronomy

基　　金：国家重点研发计划(2019YFA0405502);国家自然科学基金(12261141689)。

摘　　要：以LAMOST为代表的恒星光谱巡天获得了海量的A型星光谱。从A型星的低分辨率光谱中准确测量其大气物理参数并形成统一的处理管线的过程,往往受到特殊A型星的影响。探讨了特殊A型星Am和Ae在光学波段的光谱特征,Am星以弱的Ca II K线和强的Fe线为特征,而Ae星则以光谱中的发射线为显著特征。通过屏蔽Am和Ae星中对测量大气参数有重要影响的光谱区域,并尽量保留对恒星参数敏感的区域,获得了测量A型恒星大气参数的统一算法。该方法将应用于LAMOST DR11以及后续的数据产品中。通过对重复观测源的参数进行统计分析,有效温度(Teff)、表面重力(lg g)和金属丰度([Fe/H])的精度分别为108 K、0.103 dex和0.074 dex。通过与高分辨率星表PASTEL进行交叉对比发现,该方法获得的有效温度、表面重力和金属丰度的标准差分别为215 K、0.283 dex和0.307 dex。The stellar spectroscopic surveys represented by LAMOST have generated a vast amount of A-type star spectra.Accurately measuring the atmospheric physical parameters from low-resolution spectra of A-type stars and forming a unified processing pipeline is often affected by special A-type stars.This paper discusses the spectral features of special Atype stars,Am and Ae in the optical band.Am stars are characterized by weak Ca II lines and strong Fe lines,while Ae stars are distinguished by emission lines in their spectra.By shielding the spectral regions in Am and Ae stars that have a significant impact on the measurement of atmospheric parameters and retaining regions sensitive to stellar parameters as much as possible,we have obtained a unified algorithm for measuring the atmospheric parameters of A-type stars.This method will be applied to LAMOST Data Release 11(DR11)and subsequent data products.Through statistical analysis of parameters from repeated observations,the precisions for effective temperature(Teff),surface gravity(lg g)and metallicity([Fe/H])are found to be 108 K,0.103 dex,and 0.074 dex,respectively.External comparison analysis with the high-resolution catalog PASTEL reveals that the standard deviations for Teff,lg g,and[Fe/H]obtained by this method are 234 K,0.283 dex,and 0.327 dex,respectively.

关 键 词：A型恒星 恒星大气参数 巡天 

分 类 号：P145.1[天文地球—天体物理]