arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2101.08792astro-ph.SR
收藏

后共包络双星中的磁性白矮星

Magnetic white dwarfs in post-common-envelope binaries

S. G. Parsons, B. T. Gänsicke, M. R. Schreiber, T. R. Marsh, R. P. Ashley, E. Breedt, S. P. Littlefair, H. Meusinger

摘要:

星等有限的样本表明,20- 25%的激变变星包含磁场强度为兆高斯的白矮星,与之形成鲜明对比的是,大约5%的单个白矮星具有类似的磁场强度。此外,缺乏可识别的祖先系统的磁灾变变量导致相当大的挑战时,试图了解这些系统如何形成和演变。在这里,我们提出了一个样本的六个磁性白矮星在分离的双星与低质量的恒星同伴,我们约束的恒星和二进制参数,包括第一次,可靠的质量估计这些磁性白矮星。我们发现它们比分离双星中的无磁白矮星质量更大。这些磁性白矮星的冷却年龄通常超过1 Gyr,并且居住在非常接近罗奇叶填充的系统中。我们的研究结果更符合这些系统是暂时分离的灾变变量,而不是前灾变双星,但我们不能排除后一种可能性。我们发现,这些系统可以显示不寻常的不对称光变曲线,这可能提供一种方法来识别它们在未来的更大的数字。还提出了七个新的候选磁白矮星系统,其中三个具有不对称的光变曲线。最后,我们注意到,几个新发现的磁性系统的档案光谱中没有明确的磁性证据,这意味着这些双星以前已经错过了。然而,仍然明显缺乏年轻的分离磁白矮星系统。

英文摘要:

Magnitude-limited samples have shown that 20-25 per cent of cataclysmic variables contain white dwarfs with magnetic fields of Mega Gauss strength, in stark contrast to the approximately 5 per cent of single white dwarfs with similar magnetic field strengths. Moreover, the lack of identifiable progenitor systems for magnetic cataclysmic variables leads to considerable challenges when trying to understand how these systems form and evolve. Here we present a sample of six magnetic white dwarfs in detached binaries with low-mass stellar companions where we have constrained the stellar and binary parameters including, for the first time, reliable mass estimates for these magnetic white dwarfs. We find that they are systematically more massive than non-magnetic white dwarfs in detached binaries. These magnetic white dwarfs generally have cooling ages of more than 1 Gyr and reside in systems that are very close to Roche-lobe filling. Our findings are more consistent with these systems being temporarily detached cataclysmic variables, rather than pre-cataclysmic binaries, but we cannot rule out the latter possibility. We find that these systems can display unusual asymmetric light curves that may offer a way to identify them in larger numbers in future. Seven new candidate magnetic white dwarf systems are also presented, three of which have asymmetric light curves. Finally, we note that several newly identified magnetic systems have archival spectra where there is no clear evidence of magnetism, meaning that these binaries have been previously missed. Nevertheless, there remains a clear lack of younger detached magnetic white dwarf systems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑