Theoretical modeling of the thermal state of accreting white dwarfs undergoing classical nova cycles

被引:136
作者
Townsley, DM
Bildsten, L
机构
[1] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
[2] Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Santa Barbara, CA 93106 USA
关键词
binaries : close; novae; cataclysmic variables; nuclear reactions; nucleosynthesis; abundances; stars : dwarf novae; white dwarfs;
D O I
10.1086/379647
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
White dwarfs (WDs) experience a thermal renaissance when they receive mass from a stellar companion in a binary. For accretion rates of less than 10(-8) M-. yr(-1), the freshly accumulated hydrogen/helium envelope ignites in a thermally unstable manner that results in a classical nova (CN) outburst and ejection of material. We have undertaken a theoretical study of the impact of the accumulating envelope on the thermal state of the underlying WD. This has allowed us to find the equilibrium WD core temperatures (T-c), the CN ignition masses (M-ign), and the thermal luminosities for WDs accreting at rates of 10(-11) to 10(-8) M-. yr(-1). These accretion rates are most appropriate for WDs in cataclysmic variables (CVs) of P-orb less than or similar to7 hr, many of which accrete sporadically as dwarf novae. We have included He-3 in the accreted material at levels appropriate for CVs and find that it significantly modifies the CN ignition mass. We compare our results with several others from the CN literature and find that the inclusion of He-3 leads to lower values of M-ign for [M] over dot greater than or similar to 10(-10) M-. yr(-1) and that for [M] over dot values below this the particular author's assumption concerning T-c, which we calculate consistently, is a determining factor. Initial comparisons of our CN ignition masses with measured ejected masses find reasonable agreement and point to ejection of material comparable to that accreted.
引用
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页码:390 / 403
页数:14
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