Metal traces in white dwarfs of the SPY (ESO Supernova Ia Progenitor Survey) sample
Metal traces in white dwarfs of the SPY (ESO Supernova Ia Progenitor Survey) sample
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DOI：
10.1051/0004-6361:20041927
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发表时间：
2005-03
影响因子：
6.5
通讯作者：
D. Koester;K. Rollenhagen;R. Napiwotzki;B. Voss;N. Christlieb;D. Homeier;D. Reimers
中科院分区：
文献类型：
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作者：
D. Koester;K. Rollenhagen;R. Napiwotzki;B. Voss;N. Christlieb;D. Homeier;D. Reimers
我们在 SPY（ESO 超新星始祖巡天）巡天中以高分辨率观察到的约 800 个显然是单个白矮星的光谱中寻找微弱的 Ca II 谱线。在 24 DAZ 中检测到光球 Ca；在 25 个最热的物体中，观测到的线一定是星际线。我们还在以氦为主的大气中重新发现了 9 条强 H 线和 K 线，并首次在 8 DB 中发现了微弱的线。其中大多数也显示出微弱的氢线，因此被分类为 DBAZ。讨论了金属丰度的分布，并将其与吸积/扩散情景的预测进行了比较。我们认为，在持续不断的吸积速率随环境介质条件而变化的情况下，观察结果更容易理解，而不是在 Dupuis 等人强烈理想化的“两相吸积/扩散情况”下。 (1992, 1993a,b)。
We search for faint Ca II lines in the spectra of about 800 apparently single white dwarfs observed at high resolution for the SPY (ESO Supernova Progenitor Survey) survey. Photospheric Ca is detected in 24 DAZ; in 25 mostly hot objects the observed lines must be interstellar. We also rediscover 9 strong H and K lines in helium-dominated atmospheres and discover for the first time faint lines in 8 DB. Most of these also show faint hydrogen lines and are thus classified DBAZ. The distribution of metal abundances is discussed and compared with the predictions of the accretion/diffusion scenario. We argue that the observations are easier to understand in a scenario of continuous ongoing accretion with rates varying with the conditions of the ambient medium, rather than with the strongly idealized "two phase accretion/diffusion scenario" of Dupuis et al. (1992, 1993a,b).