The merger fraction of ultramassive white dwarfs
The merger fraction of ultramassive white dwarfs
复制标题
超大质量白矮星的合并部分
DOI：
10.1093/mnras/stac3182
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发表时间：
2022
影响因子：
4.8
通讯作者：
Dufour, P.
中科院分区：
文献类型：
--
作者：
Kilic, Mukremin;Moss, Adam G.;Kosakowski, Alekzander;Bergeron, P.;Conly, Annamarie A.;Brown, Warren R.;Toonen, Silvia;Williams, Kurtis A.;Dufour, P.
我们通过跟踪光谱学和高节奏光度学在蒙特利尔白色矮星数据库100 pc样本中的25个最大质量的白色矮星中寻找并合产物。我们发现，在这个种群中，磁白色矮星的比例异常高，达到40%。此外，我们确定了四个异常值的横向速度和检测快速旋转的五个对象。我们的研究结果表明，%的超大质量白色矮星是通过合并形成的。这一分数明显高于使用α处方（αλ = 2）的默认双星总体合成计算的预期，并为有效的轨道收缩提供了进一步的支持，例如低的公共包络效率值。
We search for merger products among the 25 most massive white dwarfs in the Montreal White Dwarf Database 100 pc sample through follow-up spectroscopy and high-cadence photometry. We find an unusually high fraction, 40 per cent, of magnetic white dwarfs among this population. In addition, we identify four outliers in transverse velocity and detect rapid rotation in five objects. Our results show thatper cent of theultramassive white dwarfs form through mergers. This fraction is significantly higher than expected from the default binary population synthesis calculations using the α prescription (with αλ = 2), and provides further support for efficient orbital shrinkage, such as with low values of the common-envelope efficiency.