湍动对流与变星脉动稳定性  

Turbulent Convection and Pulsation Stability of Stars

作　　者：熊大闰[1] 

机构地区：[1]中国科学院紫金山天文台,南京210008

出　　处：《天文学报》2017年第2期1-17,共17页Acta Astronomica Sinica

基　　金：国家自然科学基金项目(AO11373069)资助

摘　　要：对低温变星的脉动激发机制中的一些争议问题进行了评述:(1)大多数人相信γDoradus型变星是由所谓的阻塞对流机制所激发.研究表明,γDoradus和δScuti变星的激发机制不存在任何实质性的差别,他们是更大一类δScuti-γDoradus变星的2个次群:δScuti变星是p模脉动子群;而γDoradus是g模脉动子群.(2)大多数人相信太阳5分钟振荡和恒星的类太阳振荡被对流所阻尼,他们是由所谓湍流随机激发机制驱动的.研究表明,对流并非单纯只是脉动的阻尼机制,否则无法解释Mira变星和类Mira变星.利用非局部和非定常的恒星对流理论,不仅可以重现δScuti和γDoradus脉动不稳定区,也可重现低光度红巨星的类太阳振荡和高光度红巨星的类Mira振荡特性.The controversies about the excitation mechanism for cool variables are reviewed： （1） Most people believe that γ Doradus stars are excited by so called convec- tive blocking. Our researches show that the excitation of γ, Doradus has no difference from that of δ Scuti. They are two subgroups of a broader type of 5 Stuti-γ, Doradus stars： 5 Scuti is the p-mode subgroup, while γ Doradus is the g-mode subgroup. （2） Most people believe that the Solar- and Solar-like oscillations of stars are damped by convection, and they are excited by so called stochastic effects of turbulence. Our re- searches show that convection is not solely a damping mechanism for stellar oscillations, otherwise it is not able to explain the excitation of Mira and Mira-like stars. It can be repeated not only the δ Scuti and γ, Doradus strip, but also the characteristics of Solar-like and Mira-like oscillations, respectively, for the low- and high- luminosity red stars by using our non-local and time-dependent theory of convection.

关 键 词：恒星 变星 恒星 振荡 对流 

分 类 号：P144[天文地球—天体物理]