论文标题
短 - 周期性头孢虫的进化和流体动力学模型
Evolutionary and hydrodynamic models of short--period Cepheids
论文作者
论文摘要
主序列5 m_ \ odot <= m_0 <= 6.1 m_ \ odoT和氦y_0 = 0.28的初始分数丰度= 0.28，Z_0 = 0.02的最初分数丰度被带到中央氦气阶段。选定的核心氦燃烧模型被用作溶液的初始条件，用于描述头孢虫的径向搏动的流体动力学方程和时间依赖性对流。在Hertzsprung-俄罗斯图中，进化轨道被证明可以穿过M_0> 5.1m_ \ odot的不稳定条的红色边缘。计算了核心氦气的流体动力模型的网格 - 在第二个和第三个交叉处的阶段燃烧的头孢菌素的网格计算。脉动周期π和周期速率变化\dotπwer是第一个超过电脉冲脉冲的每个进化序列的星年的连续函数。计算结果与短 - period Cepheids V532 Cyg，BG CRU和RT AUR获得的\dotπ的观察估计值一致。
The evolutionary calculations for population I stars with masses on the main sequence 5 M_\odot <= M_0 <= 6.1 M_\odot and initial fractional abundances of helium Y_0=0.28 and heavier elements Z_0=0.02 were carried out to the stage of central helium exhaustion. Selected core helium--burning models were used as initial conditions for solution of the equations of hydrodynamics and time--dependent convection describing radial pulsations of Cepheids. In the Hertzsprung--Russel diagram the evolutionary tracks are shown to cross the red edge of the instability strip for M_0 > 5.1M_\odot. The grid of hydrodynamic models of core helium--burning Cepheids on the stages of the second and the third crossings of the instability strip was computed. The pulsation period Πand the rate of period change \dotΠwere determined as a continuous function of star age for each evolutionary sequence of first--overtone pulsators. Results of calculations agree with observational estimates of \dotΠrecently obtained for the short--period Cepheids V532 Cyg, BG Cru and RT Aur.
