权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Hydrodynamic Pulsation Modes of Multi-frequency Radiative Transfer for Mass-losing Early Type Stars

质量损失早型恒星多频辐射传输的水动力脉动模式

基本信息

批准号：
14540229
负责人：
AIKAWA Toshiki
金额：
$ 0.64万
依托单位：
Tohoku Gakuin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540229/
关键词：
stars stellar pulsation radiative transfer post-AGB stars chaos 脈動変光星輻射流体力学カオス現象

项目摘要

Hydrodynamic Pulsation models with an improved radiative transfer is studied. In this study, we concentrated in unified treatment of radiative transfer for linear analysis and non-linear simulation modeling.. As the first step of this study, we took non-diffusion approximation as the approximation of radiative transfer instead of equilibrium diffusion approximation. We have the fallowing results.1. We constructed computer codes for both linear analysis and non-linear simulation. We may extend the codes for the variable Eddington factor approximation for more improved treatment of radiative transfer. We applied the present codes to post-AGB stars as am example of less-massive supergiants stars as well as classical Cephieds.2. For linear analysis we compare the pulsation periods and the growth rate of models. The non- equilibrium approximation yields very small change for both the quantities. For non-linear simulation, we compared the time variations of observable quantities at the photosphere of models. The new approximation yields very small changes on these values.3. We have an interesting result on irregular pulsation of the post-AGB stars. It is known that pulsation model for post-AGB stars shows irregular pulsation fix luminous supergiant stars. The new model yields quite large different time evolution of irregular pulsation compared with ones which is obtained with the model of traditional diffusion approximation for the same values of model parameters. We suspect that the difference comes form the characteristics of chaos. In chaos system, a small change of basic equations may yield great differences of time evolution at later time, even if the calculation starts with the same initial conditions for the same model That is the case of the behavior.

本文研究了改进辐射传递的水动力脉动模型。在本研究中，我们集中在辐射传输的线性分析和非线性模拟建模的统一处理。作为研究的第一步，我们采用非扩散近似代替平衡扩散近似作为辐射传递的近似。我们有了令人失望的结果。我们构造了线性分析和非线性模拟的计算机代码。为了更好地处理辐射传递，我们可以扩展可变爱丁顿因子近似的代码。我们应用目前的代码后AGB星作为一个例子，质量较小的超巨星，以及经典的仙王座。对于线性分析，我们比较了模型的脉动周期和增长率。非平衡态近似对这两个量产生很小的变化.对于非线性模拟，我们比较了模型光球层观测量的时间变化。新的近似值对这些值产生非常小的变化。我们对后AGB星的不规则脉动有一个有趣的结果。已知后AGB星的脉动模型显示出不规则的脉动固定发光超巨星。在相同的模型参数值下，新模型与传统扩散近似模型得到的不规则脉动的时间演化有很大的差别。我们怀疑这种差异来自混沌的特性。在混沌系统中，即使对同一个模型在相同的初始条件下进行计算，基本方程的微小变化也可能在以后的时间演化中产生很大的差异。