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arXiv 1006.4451astro-ph.HE
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壳层核燃烧吸积白矮星数目和SN Ia出现率的演化

Evolution of the number of accreting white dwarfs with shell nuclear burning and of occurrence rate of SN Ia

L. R. Yungelson

摘要:

分析了半分离和分离双星中吸积的白矮星数量随时间的演化。我们考虑一个恒星系统,其中恒星形成持续10 Gyr以恒定的速率,以及一个系统,其中相同数量的恒星形成在一个单一的爆发持续1 Gyr。白矮星数量的演化与通常被认为是Ia超新星或吸积引起的坍缩的事件发生率的演化相对应,即一颗白矮星积累了一颗白矮星的质量,或一对总质量不低于白矮星质量的CO白矮星合并。在恒星形成爆发的系统中,在$t=$ 10 Gyr观测到的超软X射线源很可能不是Ia超新星的前兆。对于恒星形成速率恒定的系统中的绝大多数源来说,情况也是如此。在这两种系统中,白矮星的合并是Ia超新星的主要情况。在共生双星中,吸积的CO矮星没有积累足够的质量来进行超新星爆发,而ONeMg矮星则通过吸积引起的坍缩形成中子星来完成演化。

英文摘要:

We analyze temporal evolution of the number of accreting white dwarfs with shell hydrogen burning in semidetached and detached binaries. We consider a stellar system in which star formation lasts for 10 Gyr with a constant rate, as well as a system in which the same amount of stars is formed in a single burst lasting for 1 Gyr. Evolution of the number of white dwarfs is confronted to the evolution of occurrence rate of events that usually are identified with SN Ia or accretion-induced collapses, i.e. with accumulation of Chandrasekhar mass by a white dwarf or a merger of a pair of CO white dwarfs with total mass not lower than the Chandrasekhar one. In the systems with a burst of star formation, at $t=$10 Gyr observed supersoft X-ray sources, most probably, are not precursors of SN Ia. The same is true for an overwhelming majority of the sources in the systems with constant star formation rate. In the systems of both kinds mergers of white dwarfs is the dominant SN Ia scenario. In symbiotic binaries, accreting CO-dwarfs do not accumulate enough mass for SN Ia explosion, while ONeMg-dwarfs finish their evolution by an accretion-induced collapse with formation of a neutron star.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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