Analysis of the X-ray emission of OB stars:O stars  

作　　者：Elizaveta Ryspaeva Alexander Kholtygin 

机构地区：[1]Main(Pulkovo)Astronomical Observatory,196140 Saint Petersburg,Russia [2]Saint Petersburg State University,198504 Saint Petersburg,Russia

出　　处：《Research in Astronomy and Astrophysics》2018年第8期121-134,共14页天文和天体物理学研究（英文版）

基　　金：support from the Russian Science Foundation project No.18-12-00423;RFBR grant 18-02-00554

摘　　要：We investigate the global properties of X-ray emission from O stars, analyzing the X-ray spec- tra of 32 O stars from archival data of the XMM-Newton space observatory. We examine two hypotheses about of the origin of X-ray emission from O stars. The first is a paradigm proposed by Pollock, that was revealed from an analysis of the （ Ori X-ray observation. The second is the magnetically confined wind-shock （MCWS） model. For checking Pollock＇s hypothesis, we determine the distribution of the ratio of half width at half maximum （HWHM） to the wind terminal velocity for lines in spectra of all examined stars. In addition, we check three probable consequences from the MCWS model. We analyze if a correlation exists between the spectral hardness and such stellar parameters as the wind terminal velocity, stellar magnetic field and mass loss rate. The result showed that Pollock＇s hypothesis is not correct. We also established that not all consequences of the MCWS model considered by us are con- firmed. In addition, our spectral analysis method indicated that O stars probably have clumped stellar winds with spherical clumps.We investigate the global properties of X-ray emission from O stars, analyzing the X-ray spec- tra of 32 O stars from archival data of the XMM-Newton space observatory. We examine two hypotheses about of the origin of X-ray emission from O stars. The first is a paradigm proposed by Pollock, that was revealed from an analysis of the （ Ori X-ray observation. The second is the magnetically confined wind-shock （MCWS） model. For checking Pollock＇s hypothesis, we determine the distribution of the ratio of half width at half maximum （HWHM） to the wind terminal velocity for lines in spectra of all examined stars. In addition, we check three probable consequences from the MCWS model. We analyze if a correlation exists between the spectral hardness and such stellar parameters as the wind terminal velocity, stellar magnetic field and mass loss rate. The result showed that Pollock＇s hypothesis is not correct. We also established that not all consequences of the MCWS model considered by us are con- firmed. In addition, our spectral analysis method indicated that O stars probably have clumped stellar winds with spherical clumps.

关 键 词：STARS early-type - stars SPECTRA X-RAY 

分 类 号：P172.2[天文地球—天文学]