Non-adiabatic oscillations of red giants
Non-adiabatic oscillations of red giants
复制标题
红巨星的非绝热振荡
DOI：
10.1111/j.1365-2966.2007.11642.x
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发表时间：
2006-11
影响因子：
4.8
通讯作者：
中科院分区：
文献类型：
--
作者：
用我们的非定域含时对流理论计算了10个质量为1-3 M圆点的演化模型系列的线性非绝热振荡。结果表明，在赫兹斯普朗-拉塞尔图的低温侧存在一条红巨星不稳定带，该不稳定带沿着红巨星分支和渐近巨星分支的序列。对于较低光度的红巨星，在高阶泛音处发现脉动不稳定性;从基频到二阶泛音的低阶模是稳定的。随着光度的升高和有效温度的降低，不稳定性向低阶模移动，振荡的振幅增长率也增大。在带的高亮度端，基波和第一泛音变得不稳定，而所有四阶以上的模式变得稳定。详细研究了激发机制。结果表明，湍流压力对红变量的激发起着关键作用。冻结对流近似对具有扩展对流包层的低温星是不适用的。无论如何，这种近似既不能解释造父变星不稳定带的红边，也不能解释脉动红巨星不稳定带的蓝边。本文给出了脉动常数随恒星质量、光度和有效温度变化的解析表达式。
Using our non-local time-dependent theory of convection, the linear non-adiabatic oscillations of 10 evolutionary model series with masses of 1-3 M-circle dot are calculated. The results show that there is a red giant instability strip in the lower temperature side of the Hertzsprung-Russell diagram which goes along the sequences of the red giant branch and the asymptotic giant branch. For red giants of lower luminosities, pulsation instability is found at high order overtones; the lower order modes from the fundamental to the second overtone are stable. Towards higher luminosity and lower effective temperature, instability moves to lower order modes, and the amplitude growth rate of oscillations also grows. At the high luminosity end of the strip, the fundamental and the first overtone become unstable, while all the modes above the fourth order become stable. The excitation mechanisms have been studied in detail. It is found that turbulent pressure plays a key role for excitation of red variables. The frozen convection approximation is unavailable for the low temperature stars with extended convective envelopes. In any case, this approximation can explain neither the red edge of the Cepheid instability strip, nor the blue edge of the pulsating red giant instability strip. An analytic expression of a pulsation constant as a function of stellar mass, luminosity and effective temperature is presented from this work.
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影响因子：
6.5
作者：
M. Schultheis;I. Glass;M. Cioni
通讯作者：
M. Schultheis;I. Glass;M. Cioni
DOI：
10.1086/305601
发表时间：
1997-10
期刊：
The Astrophysical Journal
影响因子：
--
作者：
D. Xiong;L. Deng;Q. L. C. P. M. Observatory;B. Observatory;Chinese Academy of Sciences
通讯作者：
D. Xiong;L. Deng;Q. L. C. P. M. Observatory;B. Observatory;Chinese Academy of Sciences
DOI：
10.1086/152371
发表时间：
1973-09
期刊：
The Astrophysical Journal
影响因子：
--
作者：
O. Eggen
通讯作者：
O. Eggen
DOI：
10.1086/153367
发表时间：
1975-02
期刊：
The Astrophysical Journal
影响因子：
--
作者：
O. Eggen
通讯作者：
O. Eggen
DOI：
10.1046/j.1365-8711.2001.04308.x
发表时间：
2001-06
影响因子：
4.8
作者：
D. Xiong;L. Deng
通讯作者：
D. Xiong;L. Deng