A theory of hydrogen shell flashes on accreting white dwarfs. I - Their progress and the expansion of the envelope. II - The stable shell burning and the recurrence period of shell flashes-猫眼课题宝

氢壳层理论闪现了吸积白矮星的现象。

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1982

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作者：

M. Fujimoto

通过应用包络层的解析解，对吸积白矮星从点火到最后阶段的氢壳闪光进行了半解析计算。当白矮星的质量M和富氢包膜的质量M/sub 1/确定时，它们的进程是唯一确定的。由于壳层闪光引起的结构变化和由此引起的包壳膨胀主要取决于上覆层的重量P（/sub 1/）或燃烧壳层上方柱质量与白矮星表面重力的乘积。证明了当P（/下标1/）越高时，这种展开式越快、越大。当P（/sub 1/）较低时(例如<或接近。=4 × 10/sup 18/ dyn cm/sup -2/ (M = 1.0 M/sub sun/)，壳层闪光很弱，包层在膨胀到太阳半径之前就处于热平衡状态。另一方面，当P（/sub 1/）足够高（10/sup 20/ dyn cm/sup -2/）时，结构变化是如此剧烈，以至于膨胀加速超过逃逸速度，直接导致新星爆炸。由于大的P(/sub 1/)，这样的新星爆炸需要相对大质量的吸积包层。即使对于接近钱德拉塞卡质量极限的白矮星，包层的必要质量也高达10/sup -5/ M/ subsun /，而对于质量较小的白矮星，由于表面重力较低，包层的必要质量仍然较大。这些结果表明这些新星爆炸是与表面重力有关的现象。这些结果表明，这些新星爆炸是与大质量白矮星缓慢吸积有关的现象。即使对于质量最大的白矮星，吸积速率也应该低于10/sup -9/ M/sub sun/ yr/sup -1/。«少

By applying an analytical solution to the envelope, hydrogen shell flashes on accreting white dwarfs are computed semianlytically from their ignition to their final stage. When the mass of the white dwarf, M, and the mass of the hydrogen-rich envelope, ..delta..M/sub 1/, are specified, their progress is determined uniquely. Structural change and the resultant expansion of the envelope due to the shell flash depend mainly on the weight of overlying layer P(/sub 1/ or the product of the column mass above the burning shell and the surface gravity of the white dwarf. It is proved that this expansion is more rapid and greater for higher P(/sub 1/. When P(/sub 1/ is low (e.g.,< or approx. =4 x 10/sup 18/ dyn cm/sup -2/ for M = 1.0 M/sub sun/), the shell flash is weak, and the envelope settles in thermal equilibrium even before it expands to a solar radius. When P(/sub 1/ is high enough (10/sup 20/ dyn cm/sup -2/), on the other hand, the structural change is so violent that the expansion is accelerated beyond the escape velocity and leads directly to a nova explosion. Because of large P(/sub 1/, such a nova explosion requies a relatively large mass ofmore » the accreted envelope. The necessary mass of the envelope is as large as 10/sup -5/ M/sub sun/ even for white dwarfs close to the Chandrasekhar mass limit, and for less massive white dwarfs, it is still larger because of lower surface gravity. These results indicate that these nova explosions are phenomena which are related to surface gravity. These results indicate that these nova explosion are phenomena which are related to the slow accretion onto massive white dwarfs. Even for the optimal case of the most massive white dwarfs, the accretion rate should be lower than 10/sup -9/ M/sub sun/ yr/sup -1/.« less

A theory of hydrogen shell flashes on accreting white dwarfs. I - Their progress and the expansion of the envelope. II - The stable shell burning and the recurrence period of shell flashes

氢壳层理论闪现了吸积白矮星的现象。

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