Measuring M dwarf winds with DAZ white dwarfs

被引:61
作者
Debes, John H. [1 ]
机构
[1] Carnegie Inst Sci, Dept Terr Magnetism, Washington, DC 20015 USA
关键词
circumstellar matter; stars : late-type; stars; winds; outflows; white dwarfs;
D O I
10.1086/508132
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Hydrogen atmosphere white dwarfs with metal lines, so-called DAZs, show evidence for ongoing accretion of material onto their surfaces. Some DAZs are known to have unresolved M dwarf companions, which could account for the observed accretion through a stellar wind. I combine observed Ca abundances of the DAZs with information on the orbital separation of their M dwarf companions to infer the mass-loss rate of the M dwarfs. I find that for three of the six known DAZs with M dwarf companions, a stellar wind can plausibly explain the observed accretion on the white dwarfs assuming Bondi-Hoyle accretion of solar abundance stellar winds on the order of 10(-14) to 10(-16) M-circle dot yr(-1). The rest of the sample have companions with orbits >= 1 AU and require companion mass-loss rates of > 10(-11) M-circle dot yr(-1). I conclude that there must be an alternative explanation for accretion of material onto DAZs with widely separated companions. The inferred winds for two of the close binaries are orders of magnitude smaller than typically assumed for the angular momentum loss of red dwarf-white dwarf pairs due to magnetic braking from a stellar wind and may seriously affect predictions for the formation rate of CVs with low-mass companions.
引用
收藏
页码:636 / 642
页数:7
相关论文
共 60 条
[1]   COOL METALLIC-LINE WHITE-DWARFS, RADIAL-VELOCITIES, AND INTERSTELLAR ACCRETION [J].
AANNESTAD, PA ;
KENYON, SJ ;
HAMMOND, GL ;
SION, EM .
ASTRONOMICAL JOURNAL, 1993, 105 (03) :1033-1044
[2]   ON THE NUMBER OF COMETS AROUND OTHER SINGLE STARS [J].
ALCOCK, C ;
FRISTROM, CC ;
SIEGELMAN, R .
ASTROPHYSICAL JOURNAL, 1986, 302 (01) :462-476
[3]  
Althaus LG, 1998, MON NOT R ASTRON SOC, V296, P206, DOI 10.1046/j.1365-8711.1998.01332.x
[4]   Cataclysmic variables: An empirical angular momentum loss prescription from open cluster data [J].
Andronov, N ;
Pinsonneault, M ;
Sills, A .
ASTROPHYSICAL JOURNAL, 2003, 582 (01) :358-368
[5]  
Badalyan O. G., 1992, Soviet Astronomy, V36, P70
[6]  
Baraffe I, 1998, ASTRON ASTROPHYS, V337, P403
[7]   On the mechanism of accretion by stars [J].
Bondi, H ;
Hoyle, F .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1944, 104 (01) :0273-0282
[8]   The precataclysmic binary RR Caeli revisited: Spectroscopy and light-curve synthesis [J].
Bruch, A .
ASTRONOMICAL JOURNAL, 1999, 117 (06) :3031-3040
[9]   Cool customers in the stellar graveyard. III. Limits to substellar objects around nearby white dwarfs using the Canada-France- Hawaii telescope [J].
Debes, JH ;
Ge, J ;
Ftaclas, C .
ASTRONOMICAL JOURNAL, 2006, 131 (01) :640-647
[10]   Cool customers in the stellar graveyard. I. Limits to extrasolar planets around the white dwarf G29-38 [J].
Debes, JH ;
Sigurdsson, S ;
Woodgate, BE .
ASTROPHYSICAL JOURNAL, 2005, 633 (02) :1168-1174