arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2006.00965astro-ph.SR
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40 pc I以内的$\textit{Gaia}$白矮星:新候选者的光谱观测

$\textit{Gaia}$ white dwarfs within 40 pc I: spectroscopic observations of new candidates

P. -E. Tremblay, M. A. Hollands, N. P. Gentile Fusillo, J. McCleery, P. Izquierdo, B. T. Gänsicke, E. Cukanovaite, D. Koester, W. R. Brown, S. Charpinet, T. Cun… 展开作者

P. -E. Tremblay, M. A. Hollands, N. P. Gentile Fusillo, J. McCleery, P. Izquierdo, B. T. Gänsicke, E. Cukanovaite, D. Koester, W. R. Brown, S. Charpinet, T. Cunningham, J. Farihi, N. Giammichele, V. van Grootel, J. J. Hermes, M. J. Hoskin, S. Jordan, S. O. Kepler, S. J. Kleinman, C. J. Manser, T. R. Marsh, D. de Martino, A. Nitta, S. G. Parsons, I. Pelisoli, R. Raddi, A. Rebassa-Mansergas, J. -J. Ren, M. R. Schreiber, R. Silvotti, O. Toloza, S. Toonen, S. Torres

摘要:

我们提出了一个光谱调查的230个白矮星候选人在40 pc的太阳从威廉赫歇尔望远镜和大加那利望远镜。所有候选者都是从$\textit{Gaia}$数据发布2(DR2)中选择的,并且几乎所有情况下都没有先前的光谱分类。我们总共发现了191颗确认的白矮星和39颗主序星污染物。样本中的大多数恒星残骸都相对较冷($\langle T_{\rm eff} \rangle$ = 6200 K),显示出氢巴耳末线或无特征的光谱,分别对应于89 DA和76 DC白矮星。我们还恢复了两个DBA白矮星和9 - 10的磁性残留物。我们发现了两颗含碳DQ星和14颗新的富金属白矮星。这包括可能探测到第一颗带有金属线的超冷白矮星。我们描述了三个DZ星,我们发现至少有四种不同的金属物种,包括一个强烈的Fe和Ni丰富,吸积的星子与核心地球组成的指示。我们发现了一颗质量极大的(1.31 $\pm$ 0.01 M $_{\odot}$)DA白矮星,它显示出微弱的巴耳末线,可能表明了恒星的磁性。另一颗白矮星显示出强烈的巴耳末线发射,但没有红外线过量,这表明它是一颗低质量的亚恒星伴星。在北半球($δ>$ 0 deg),位于赫兹-罗素图中白矮星冷却轨道上,40 pc样本内的$\textit{Gaia}$ DR 2源现在已经达到了高光谱完整性($>$ 99%)。一个完整的北方样本的统计研究是在一个配套文件。

英文摘要:

We present a spectroscopic survey of 230 white dwarf candidates within 40 pc of the Sun from the William Herschel Telescope and Gran Telescopio Canarias. All candidates were selected from $\textit{Gaia}$ Data Release 2 (DR2) and in almost all cases had no prior spectroscopic classifications. We find a total of 191 confirmed white dwarfs and 39 main-sequence star contaminants. The majority of stellar remnants in the sample are relatively cool ($\langle T_{\rm eff} \rangle$ = 6200 K), showing either hydrogen Balmer lines or a featureless spectrum, corresponding to 89 DA and 76 DC white dwarfs, respectively. We also recover two DBA white dwarfs and 9--10 magnetic remnants. We find two carbon-bearing DQ stars and 14 new metal-rich white dwarfs. This includes the possible detection of the first ultra-cool white dwarf with metal lines. We describe three DZ stars for which we find at least four different metal species, including one which is strongly Fe- and Ni-rich, indicative of the accretion of a planetesimal with core-Earth composition. We find one extremely massive (1.31 $\pm$ 0.01 M$_{\odot}$) DA white dwarf showing weak Balmer lines, possibly indicating stellar magnetism. Another white dwarf shows strong Balmer line emission but no infrared excess, suggesting a low-mass sub-stellar companion. High spectroscopic completeness ($>$99%) has now been reached for $\textit{Gaia}$ DR2 sources within 40 pc sample, in the northern hemisphere ($δ>$ 0 deg) and located on the white dwarf cooling track in the Hertzsprung-Russell diagram. A statistical study of the full northern sample is presented in a companion paper.

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