EX Lupi: History and spectroscopy
EX Lupi: History and spectroscopy
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DOI：
10.1086/517494
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发表时间：
2007-06-01
影响因子：
5.3
通讯作者：
Herbig, G. H.
中科院分区：
文献类型：
--
作者：
Herbig, G. H.
EX Lupi是“EXor”类的原型，EXor类是主序前的变量，通常保持在最低光照下，但会发生相对短暂（几个月到几年）的几个量级的耀斑。本文研究了EX Lup本身的已知信息，并描述了1995年至2005年期间收集的新光度和光谱信息，在此期间星星经历了四次耀斑。它的结论是，在协议与以前的调查，耀斑是由于间歇性的质量下降。证据：M0型吸收光谱的遮蔽，在许多发射线上出现位移达+340 km s（-1）的反向P Cyg型吸收成分，以及发射线结构的显著变化。这些现象是否也被其他EXOR所共享，还有待观察，这些EXOR通常根据零碎的观测证据被归类为EXOR。
EX Lupi is the prototype of the "EXor'' class, which are pre-main-sequence variables that normally remain at minimum light, but are subject to relatively brief ( a few months to a few years) flare-ups of several magnitudes amplitude. This paper examines what is known about EX Lup itself, and describes new photometric and spectroscopic information collected between 1995 and 2005, during which time the star underwent four flare-ups. It is concluded, in agreement with previous investigations, that the flare-ups are due to intermittent mass infall. The evidence: veiling of the M0-type absorption spectrum, appearance of reversed P Cyg-type absorption components displaced up to +340 km s(-1) at many emission lines, and striking variations in emission-line structure. It remains to be seen whether these phenomena are shared by other EXors, which are often classified as such on the basis of fragmentary observational evidence.