恒星类太阳和类长周期变星脉动激发机制的理论探讨  

A Theoretical Probe for Excitation Mechanism of Solar-like and Mira-like Oscillations of Stars

作　　者：熊大闰[1] 邓李才[2] 

机构地区：[1]中国科学院紫金山天文台,南京210008 [2]中国科学院国家天文台,北京100012

出　　处：《天文学报》2013年第1期20-26,共7页Acta Astronomica Sinica

基　　金：国家自然科学基金项目(11073053,10973015)资助

摘　　要：利用一种非局部和非定常的恒星对流理论,计算了0.6～3.0 M_⊙恒星演化模型的线性非绝热脉动.结果表明,赫罗图上脉动不稳定带右方的脉动不稳定的低温恒星可以分成2大类(群).一类由主序矮星、亚巨星和中低光度红巨星组成的类太阳振荡恒星,它们的中高阶(径向阶n_r≥12)p模是脉动不稳定的,而低阶(n_r≤5)模是脉动稳定的;另一类是由亮的红巨星和渐近巨星支星(AGB)组成的类长周期变星,它们的低阶模(n_r≤5)是脉动不稳定的,而高阶模(n_r≥12)却是脉动稳定的.能利用对流与脉动的耦合统一解释造父变星脉动不稳定带红边界、类太阳和类长周期变星脉动.对赫罗图右方的低温恒星的中低阶p模振荡,对流与脉动的耦合是主要的脉动激发和阻尼机制,而湍流的随机激发机制仅对类太阳振荡高阶p模重要.The linear stability analysis of the radial and non-radial oscillations for the evolutionary models of the star with a mass of 0.6-3 M⊙ is taken by using a nonlocal and time-dependent convection theory. The results show that the unstable low-temperature stars on the right side of instability strip can be divided into two groups. One is the solar-like oscillation stars composed of the main-sequence dwarfs, subgiants and low- and intermediate-luminous red giants, which are unstable in the intermediate- and high-order （n 〉 12） p-modes and stable in the low-order （n 〈 5） p-modes. Another is the Mira-like stars composed of the lulninous red giants and AGB stars, which are just contrary to the solar-like stars, unstable in the low-order （n 〈 5） p-modes and stable in the intermediate- and high-order （n ≥ 12） p-modes. The red edge of Cepheid （d Seuti） instability strip, the oscillations of solar-like and Mira-like stars can be explained uniformly by the coupling between convection and oscillations （CCO） of instability strip, CCO is the dominant For the low-temperature stars on the right side excitation and damping mechanism for the low- and intermediate-order p-modes, and the turbulent stochastic excitation becomes important only for the high-order p-modes of solar-like oscillations.

关 键 词：恒星 振荡 太阳 振荡 恒星 变星 

分 类 号：P144[天文地球—天体物理]