论文标题
行星星云SWST \，1：巨大的后AGB恒星中的热脉冲的冷却中央恒星？
The cooling-down central star of the planetary nebula SwSt\,1: a late thermal pulse in a massive post-AGB star?
论文作者
论文摘要
SWST 1（PN G001.5-06.7）是一个明亮而紧凑的行星星云，其中包含较晚的[WC]型中心星。先前的研究表明，随着时间的推移，烟囱和恒星线正在缓慢变化。我们研究了物体的新的和档案的光学和紫外光谱。 [OIII] 4959和5007 A至$ \ MATHRM {H}β$线通量比在1976年至1997/2015年之间降低。恒星光谱还显示了这些时期之间的变化。我们建模了在不同时期观察到的恒星和网状光谱。分析表明，在1976年至1993年之间，恒星温度从约42 kk降至40.5 kk。我们在1993年至2015年之间没有检测到显着变化。观察结果表明，该恒星在H-R图中进行了循环。当壳源在AGB后演变中激活壳源时，这是可能的。我们推断出大量的后AGB恒星经历的晚期热脉冲（LTP）可以解释中央恒星的演变。由于LTP的结果，这样的恒星并没有大大扩展，也没有成为一个重生的红色巨人。但是，释放的能量可以消除恒星的微小信封。
SwSt 1 (PN G001.5-06.7) is a bright and compact planetary nebula containing a late [WC]-type central star. Previous studies suggested that the nebular and stellar lines are slowly changing with time. We studied new and archival optical and ultraviolet spectra of the object. The [OIII] 4959 and 5007 A to $\mathrm{H}β$ line flux ratios decreased between about 1976 and 1997/2015. The stellar spectrum also shows changes between these epochs. We modeled the stellar and nebular spectra observed at different epochs. The analyses indicate a drop of the stellar temperature from about 42 kK to 40.5 kK between 1976 and 1993. We do not detect significant changes between 1993 and 2015. The observations show that the star performed a loop in the H-R diagram. This is possible when a shell source is activated during its post-AGB evolution. We infer that a late thermal pulse (LTP) experienced by a massive post-AGB star can explain the evolution of the central star. Such a star does not expand significantly as the result of the LTP and does not became a born-again red giant. However, the released energy can remove the tiny H envelope of the star.
