球状星团中低光度红巨星的脉动稳定性

利用一种非定常的恒星非局部对流理论,对球状星团中低光度的红巨星进行了线性非绝热脉动理论计算．结果表明,对所有温度高于约5400 K模型的基音到4阶泛音都是脉动稳定的．随着恒星光度的增大,低阶泛音也变得脉动不稳定．对中低光度的红巨星,脉动稳定性非常低,接近中性稳定．因此他们将是不变星或非常小振幅的短周期变星(P<2天)．

Pulsational Stability for Intermediate-and low-Luminosity Red Stars of Globular Cluster

Using a time-dependent theory non-local of convection, the linear non-adiabatic oscillations for intermediate- and low-luminosity red giants of globular cluster were calculated. The results show that all the models, temperature of which is higher than 5400 K, are pulsationally stable from fundamental modes to fourth overtone. The high-order modes become unstable with decrease of effective temperature of stars. The low-order modes become unstable with inclease of luminosity. The pulsational stability is very low and near to neutral stability for the intermediate- and low-luminosity red giants. Therefore, they should be constant stars or very-small-amplitude , short-period (P < 2 day) variables.