论文标题
BPS CS 22940-0009的光谱分析：连接进化的氦星
Spectroscopic analysis of BPS CS 22940-0009: connecting evolved helium stars
论文作者
论文摘要
BPS CS 22940-0009是富含氦气的B-Star，具有与富含氦气的B分量和极端氦星的特征。从盐观测值分析了BPS CS 22940-0009的光谱。发现大气参数为$ t _ {\ rm eff} = 34970 \ pm 370 $ k，$ \ log g/{\ rm cm cm \ \，s^{ - 2}} = 4.79 \ 4.79 \ pm 0.17 $，pm 0.17 $，$ n _ { $ n _ {\ rm c}/n _ {\ rm he} \ simeq 0.007 $，$ n _ {\ rm n}/n _ {\ rm he} \ simeq 0.002 $，尽管对氦气线的进一步改进是值得的。这将恒星作为HE-SDB和EHE种群之间的链接，$ g $ -T $ Space。丰度概况显示了CNO加工中N的富集，以及C $3α$燃烧的C。 Fe的Al，Si，S和Fe上极限的耗竭显示恒星本质上是金属丧失的。结果与BPS CS 22940-0009是一致的，该BPS由两个氦白色矮人合并而形成，目前朝着氦气主序列发展。
BPS CS 22940-0009 is a helium-rich B-star that shares characteristics with both helium-rich B subdwarfs and extreme helium stars. The optical spectrum of BPS CS 22940-0009 has been analysed from SALT observations. The atmospheric parameters were found to be $T_{\rm eff} = 34970 \pm 370$ K, $\log g/{\rm cm \, s^{-2}} = 4.79 \pm 0.17$, $n_{\rm H}/n_{\rm He} \simeq 0.007$, $n_{\rm C}/n_{\rm He} \simeq 0.007$, $n_{\rm N}/n_{\rm He} \simeq 0.002$, although further improvement to the helium line fits would be desirable. This places the star as a link between the He-sdB and EHe populations in $g$-$T$ space. The abundance profile shows enrichment of N from CNO-processing, and C from $3α$ burning. Depletion of Al, Si, S and a low upper limit for Fe show the star to be intrinsically metal-poor. The results are consistent with BPS CS 22940-0009 having formed from the merger of two helium white dwarfs and currently evolving toward the helium main sequence.
