Observations of ultracool white dwarfs

被引：46
作者：
Oppenheimer, BR
Saumon, D
Hodgkin, ST
Jameson, RF
Hambly, NC
Chabrier, G
Filippenko, AV
Coil, AL
Brown, ME
机构：
[1] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA
[2] Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA
[3] Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England
[4] Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England
[5] Univ Edinburgh, Inst Astron, Edinburgh EH9 3HJ, Midlothian, Scotland
[6] Ecole Normale Super Lyon, CRAL, CNRS, UMR 5574, F-69364 Lyon 07, France
[7] CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA
来源：
ASTROPHYSICAL JOURNAL | 2001年 / 550卷 / 01期
关键词：
stars : fundamental parameters; stars; individual; (LHS; 3250; WD; 0346+246); white dwarfs;
D O I：
10.1086/319718
中图分类号：
P1 [天文学];
学科分类号：
0704 ;
摘要：
We present new spectroscopic and photometric measurements of the white dwarfs LHS 3250 and WD 0346+246. Along with F351-50, these white dwarfs are the coolest ones known, all with effective temperatures below 4000 K. Their membership in the Galactic halo population is discussed, and detailed comparisons of all three objects with new atmosphere models are presented. The new models consider the effects of mixed H/He atmospheres and indicate that WD 0346+246 and F351-50 have predominantly helium atmospheres with only traces of hydrogen. LHS 3250 may be a double degenerate whose average radiative temperature is between 2000 and 4000 K, but the new models fail to explain this object.
引用
收藏
页码：448 / 456
页数：9
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