The discovery of a companion to the lowest mass white dwarf

被引：31
作者：
Kilic, Mukremin [1 ]
Brown, Warren R.
Prieto, Carlos Allende
Pinsonneault, M. H.
Kenyon, S. J.
机构：
[1] Ohio State Univ, Dept Astron, Columbus, OH 43210 USA
[2] Smithsonian Astrophys Observ, Cambridge, MA 02138 USA
[3] Univ Texas, McDonald Observ, Austin, TX 78712 USA
[4] Univ Texas, Dept Astron, Austin, TX 78712 USA
来源：
ASTROPHYSICAL JOURNAL | 2007年 / 664卷 / 02期
关键词：
stars : individual (SDSS J091709.55+463821.8); stars; low-mass; brown dwarfs; white dwarfs;
D O I：
10.1086/518735
中图分类号：
P1 [天文学];
学科分类号：
0704 ;
摘要：
We report the detection of a radial velocity companion to SDSS J091709.55+463821.8, the lowest mass white dwarf currently known, with M similar to 0.17 M-circle dot. The radial velocity of the white dwarf shows variations with a semi-amplitude of 148.8 +/- 6.9 km s(-1) and a period of 7.5936 +/- 0: 0024 hr, which implies a companion mass of M >= 0.28 M-circle dot. The lack of evidence of a companion in the optical photometry forces any main-sequence companion to be smaller than 0.1 M-circle dot, hence a low-mass main-sequence star companion is ruled out for this system. The companion is most likely another white dwarf, and we present tentative evidence for an evolutionary scenario that could have produced it. However, a neutron star companion cannot be ruled out, and follow-up radio observations are required to search for a pulsar companion.
引用
收藏
页码：1088 / 1092
页数：5
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