Metal abundances in the hottest known DO white dwarf (KPD 0005+5106)
Metal abundances in the hottest known DO white dwarf (KPD 0005+5106)
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已知最热的 DO 白矮星中的金属丰度 (KPD 0005 5106)
DOI：
10.1051/0004-6361/201015007
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发表时间：
2010
影响因子：
6.5
通讯作者：
J. Kruk
中科院分区：
文献类型：
--
作者：
Daniel Wassermann;K. Werner;T. Rauch;J. Kruk
对KPD 0005 +5106的紫外光谱和可见光谱进行了分析。重新确定的大气参数是必要的，因为最近发现的高度电离的金属（氖八，钙x）表明，有效温度是显着高于以前认为的。在这里，我们宣布发现了来自高度电离的硅、硫和铁（Si VII、S VII、Fe x）的谱线，这些谱线以前从未在任何恒星光球中发现过。我们对这些谱线以及氦和其他几种金属谱线的分析得出T_eff = 200000 ± 20000 K，log g = 6.7 ± 0.3。质量和光度与演化轨迹比较：M = 0.64 M，log L/L = 3.7，所以严格来说，这颗星星是一颗燃烧氦的前白矮星。在以氦为主的大气中，金属的质量分数在0.7-4.3太阳能的范围内。氢是不可检测的，我们得出的丰度上限为0.034太阳能。这种丰度模式可能不受重力沉降和辐射悬浮的影响。它的起源在于以前的进化阶段。我们讨论了KPD 0005 +5106与RCrB星的联系，以及它可能是由双简并事件引起的。
We present the analysis of ultraviolet and optical spectra of KPD0005+5106. Redetermination of the atmospheric parameters is necessary because the recent discovery of highly ionised metals (Ne VIII, Ca x) indicates that the effective temperature is significantly higher than previously thought. Here we announce the discovery of lines from highly ionised silicon, sulphur, and iron (Si VII, S VII, Fe x) which were never found before in any stellar photosphere. Our analysis of these lines and those from helium and several other metals gives T eff = 200000 ± 20000 K, log g = 6.7 ± 0.3. Mass and luminosity follow from a comparison with evolutionary tracks: M = 0.64 M ⊙ and log L/L ⊙ = 3.7, so that, strictly speaking, the star is a helium-burning pre-white dwarf. The mass fractions of the metals in the helium-dominated atmosphere are in the range 0.7-4.3 solar. Hydrogen is not detectable and we derive an upper abundance limit of 0.034 solar. This abundance pattern is probably unaffected by gravitational settling and radiative levitation. Its origin lies in previous evolutionary stages. We discuss the link of KPD0005+5106 to RCrB stars and the possibility that it results from a double-degenerate merger event.
影响因子：
3.5
作者：
K. Werner;F. Herwig
通讯作者：
K. Werner;F. Herwig