X-ray Activity from Different Types of Stars
Abstract
X-ray emission is an important indicator of stellar activity. In this paper, we study stellar X-ray activity using the XMM-Newton and LAMOST data for different types of stars. We provide a sample including 1259 X-ray emitting stars, of which 1090 have accurate stellar parameter estimations. Our sample size is much larger than those in previous works. We find a bimodal distribution of X-ray to optical flux ratio (log(fX/fV)) for G and K stars. We interpret that this bimodality is due to two subpopulations with different coronal heating rates. Furthermore, using the full widths at half maxima calculated from H{\alpha} and H\b{eta} lines, we show that these stars in the inactive peaks have smaller rotational velocities. This is consistent with the magnetic dynamo theory that stars with low rotational velocities have low levels of stellar activity. We also examine the correlation between log(fX/fV) and luminosity of the excess emission in the H{\alpha} line, and find a tight relation between the coronal and chromospheric activity indicators.
Keywords
Cite
@article{arxiv.1902.00856,
title = {X-ray Activity from Different Types of Stars},
author = {Lin He and Song Wang and Xiaojie Xu and Roberto Soria and Jifeng Liu and Xiangdong Li and Yu Bai and Zhongrui Bai and Jincheng Guo and Yanli Qiu and Yong Zhang and Ruochuan Xu and Kecheng Qian},
journal= {arXiv preprint arXiv:1902.00856},
year = {2019}
}
Comments
25 pages, 19 figures, 3 tables. Accepted for publication in RAA