The Radial Velocity Measurement Accuracy of Different Spectral Type Low Resolution Stellar Spectra at Different Signal-to-Noise Ratio
WANG Feng-fei1，2, LUO A-li1, ZHAO Yong-heng1
1. National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China 2. University of Chinese Academy of Sciences, Beijing 100049, China
Abstract：The radial velocity of the star is very important for the study of the dynamics structure and chemistry evolution of the Milky Way, is also an useful tool for looking for variable or special objects. In the present work, we focus on calculating the radial velocity of different spectral types of low-resolution stellar spectra by adopting a template matching method, so as to provide effective and reliable reference to the different aspects of scientific research. We choose high signal-to-noise ratio (SNR) spectra of different spectral type stellar from the Sloan Digital Sky Survey (SDSS), and add different noise to simulate the stellar spectra with different SNR. Then we obtain the radial velocity measurement accuracy of different spectral type stellar spectra at different SNR by employing a template matching method. Meanwhile, the radial velocity measurement accuracy of white dwarf stars is analyzed as well. We concluded that the accuracy of radial velocity measurements of early-type stars is much higher than late-type ones. For example, the 1-sigma standard error of radial velocity measurements of A-type stars is 5~8 times as large as K-type and M-type stars. We discuss the reason and suggest that the very narrow lines of late-type stars ensure the accuracy of measurement of radial velocities, while the early-type stars with very wide Balmer lines, such as A-type stars, become sensitive to noise and obtain low accuracy of radial velocities. For the spectra of white dwarfs stars, the standard error of radial velocity measurement could be over 50 km·s-1 because of their extremely wide Balmer lines. The above conclusion will provide a good reference for stellar scientific study.
王凤飞1, 2, 罗阿理1, 赵永恒1 . 不同光谱型的低分辨率恒星光谱在不同信噪比条件下视向速度测量精度的分析 [J]. 光谱学与光谱分析, 2014, 34(02): 565-568.
WANG Feng-fei1，2, LUO A-li1, ZHAO Yong-heng1 . The Radial Velocity Measurement Accuracy of Different Spectral Type Low Resolution Stellar Spectra at Different Signal-to-Noise Ratio . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2014, 34(02): 565-568.
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