首页     开始     To Survive in the Universe    
Inhabited Sky
    News@Sky     天文图片     收集     论坛     Blog New!     常见问题     新闻     登录  

HD 190946


目录

图像

上传图像

DSS Images   Other Images


相关文章

The X-Ray Emission of A-Type Stars
From X-ray images in the ROSAT public archives, we determine soft X-rayfluxes, or flux upper limits, for 74 A-type stars, which have beenobserved during deep integrations with the PSPC. Nine supposedly single,late A stars (0.20 < B-V < 0.35) are found to coincide with X-raysources. The X-ray luminosities we infer for these stars range fromlevels comparable to the Active Sun, at log L_x ~27.6, to much brighteremission levels similar to those observed for active late-type binarysystems, near log L_x ~30.1. Another 10 sources are identified withearly A stars (0.0 < B-V < 0.2). Five of these are confirmeddouble stars, the rest are ostensibly single. The maximum luminosity wedetect in the early A stars, log L_x = 30.1, is 3.5 orders of magnitudebrighter than the X-ray upper limits for the nondetected stars.Additional study, including radial velocity monitoring and/or opticalinterferometry, will be needed to determine whether the putativelysingle X-ray emitting stars are in fact single, or whether theiremission is produced entirely or in part by unknown or unresolved binarycompanions. The level of X-ray emission associated with chemicallynormal, single A stars thus far appears to be uncorrelated with anyobvious stellar property, including the rotation rate, which is known togreatly influence the dynamo activity and the X-ray emission levels oflower mass stars. (SECTION: Stars)

提交文章


相关链接

  • - 没有找到链接 -
提交链接


下列团体成员


观测天体数据

星座:狐狸座
右阿森松:20h06m40.19s
赤纬:+22°42'43.1"
视星:7.878
距离:869.565 天文距离
右阿森松适当运动:0.1
赤纬适当运动:-6.8
B-T magnitude:7.822
V-T magnitude:7.874

目录:
适当名称   (Edit)
HD 1989HD 190946
TYCHO-2 2000TYC 2154-3733-1
USNO-A2.0USNO-A2 1125-15097497
HIPHIP 99058

→ 要求更多目录从vizier