AI 中文总结
研究四颗冷且金属污染严重的H大气白矮星，通过多种方法分析其大气参数，测量金属丰度，识别出多种独特金属，发现不同白矮星吸积的星子成分各异，增加了严重污染冷白矮星样本。
AI 中文摘要
我们展示了对用X-shooter观测的四颗冷且金属污染严重的H大气白矮星的分析。我们比较了通过光谱学、光度测量和一种混合方法获得的它们的大气参数，发现三种分析之间有效温度的差异高达约160K，表面重力对数的差异约为0.3 dex。我们采用光度分析中的有效温度和表面重力，随后通过光谱建模测量光球元素的金属丰度并分析其组成。我们在四颗白矮星的光球中识别出5到11种独特金属，总吸积率在10^8到10^9 g s^-1之间。对WD J035826.49+215726.16的成分分析表明，其吸积的星子类似于富含核心的分化天体，核心质量分数为70%，使其成为已知被白矮星吸积的最富含核心的天体之一。WD J042643.98−415341.44吸积的母体与地球相比钠含量增加，使其与原始球粒陨石最为相似。WD J013222.88+052923.71的光球中类似核心的物质大量耗尽，其成分类似于纯地壳/地幔物质。WD J232428.21−021643.65吸积了最富含铁的星子，铁质量分数为67%。我们将这些结果与其他已发表的研究进行比较并得出结论，这些白矮星是迄今为止研究的污染最严重的冷DAZ之一，使具有五种或更多金属的冷H主导白矮星样本增加了50%。
英文摘要
We present the analysis of four cool and strongly metal-polluted H-atmosphere white dwarfs observed with X-shooter. We compared their atmospheric parameters obtained from spectroscopy, photometry and a hybrid method, finding a difference of up to $\simeq160$ K in $T_\mathrm{eff}$, and $\simeq0.3$ dex in $\log g$, between the three analyses. We adopt the $T_\mathrm{eff}$ and $\log g$ from the photometric analysis, and subsequently measured the metal abundances of the photospheric elements from spectroscopic modelling, analysing their compositions. We identified from five to eleven unique metals in the photospheres of the four white dwarfs, with total accretion rates ranging from $10^{8}$ to $10^{9}$ $\mathrm{g~s^{-1}}$. The compositional analysis of WD J035826.49$+$215726.16 suggests an accreted planetesimal akin to a core-rich differentiated body, with a core mass fraction of 70 per cent, placing it among the most core-rich objects known to be accreted by white dwarfs. The parent body accreted by WD J042643.98$-$415341.44 shows an enhancement in Na compared to that of the Earth, making it most similar to primitive chondrites. The photosphere of WD J013222.88$+$052923.71 is greatly depleted in core-like material, and its composition resembles that of pure crust/mantle material. WD J232428.21$-$021643.65 has accreted the most Fe-rich planetesimal, with an Fe mass fraction of 67 per cent. We compare these results to other published studies and conclude that these white dwarfs are among the most heavily polluted cool DAZs studied to date, increasing the sample of cool H-dominated white dwarfs with five or more metals by 50 per cent.
Comments21 pages, 15 figures, accepted by MNRAS
Journal refMon Not R Astron Soc (2026)
