Discovery of an ultracool white dwarf companion

被引：19

作者：

Farihi, J ^{[1
]}

机构：

[1] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA

来源：

ASTROPHYSICAL JOURNAL | 2004年 / 610卷 / 02期

关键词：

binaries : general; stars : fundamental parameters; stars : individual (GD 392); white dwarfs;

D O I：

10.1086/382682

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

The discovery of a low-luminosity common proper-motion companion to the white dwarf GD 392 at a wide separation of 46" is reported. BVRI photometry suggests a low temperature (T(eff)similar to4000 K), while JHK data strongly indicate suppressed flux at all near-infrared wavelengths. Thus, GD 392B is one of the few white dwarfs to show significant collision-induced absorption due to the presence of photospheric H-2 and the first ultracool white dwarf detected as a companion to another star. Models fail to explain GD 392B as a normal-mass white dwarf. If correct, the cool companion may be explained as a low-mass white dwarf or unresolved double degenerate. The similarities of GD 392B to known ultracool degenerates are discussed, including some possible implications for the faint end of the white dwarf luminosity function.

引用

页码：1013 / 1020

页数：8