标题： 差分自转对类太阳脉动体中声学模随机激励的影响 显示英文标题

标题： The impact of differential rotation on the stochastic excitation of acoustic modes in solar-like pulsators

摘要： 声学模态由太阳类恒星外对流包层中的湍流对流激发。 来自星震学研究的观测结果表明，44%的太阳类恒星不表现出可检测到的随机激发的声学模态。 这种现象似乎与其旋转速率和磁活动有关。 在第一篇论文中，我们表明均匀旋转会显著减小模态振幅。 然而，太阳型恒星的对流包层是差旋的：中纬度和赤道之间的旋转速率差异可以达到60%，如最近的星震学研究所示。 在本文中，我们研究了差旋对太阳类恒星中声学模态随机激发的影响。 我们提供了对差旋太阳类恒星中声学模态激发的理论预测。 我们使用旋转混合长度理论方法来模拟差旋对对流的局部影响。 然后，我们通过结合MESA恒星结构和演化代码以及GYRE恒星脉动代码，数值估算湍流对流对振荡模态功率注入的影响。 我们表明，对于具有相同平均旋转速率$5 \Omega_{\odot}$但不同差旋速率的恒星，注入声学模态的功率差异可达30%。 在反向差旋区域，即恒星极点比赤道旋转更快的情况下，轴对称声学模态的激发进一步受到抑制，与均匀旋转情况相比。 这可能会阻碍在这种配置下的模态检测。 本研究首次预测了太阳类脉动星中声学模态激发随差旋的变化情况。 显示英文摘要

摘要： Acoustic modes are excited by turbulent convection in the outer convective envelope of solar-like stars. Observational results from asteroseismic studies show that 44% of solar-like stars do not present detectable stochastically-excited acoustic modes. This phenomenon appears to be related to their rotation rate and magnetic activity. In a first paper, we showed that uniform rotation tends to diminish the mode amplitudes significantly. However, convective envelopes in solar-type stars are differentially rotating: the rotation rate difference between mid-latitudes and the equator can go up to 60%, as shown by recent asteroseismic works. In this paper, we examine the impact of differential rotation on the stochastic excitation of acoustic modes in solar-like stars. We provide theoretical predictions for the excitation of acoustic modes in a differentially rotating solar-like star. We use the Rotating Mixing-Length Theory approach to model the local influence of differential rotation on convection. We then estimate the resulting impact on power injection by turbulent convection into oscillation modes numerically, using a combination of the MESA stellar structure and evolution code and GYRE stellar pulsation code. We show that the power injected in acoustic modes differs by up to 30 % for stars with the same mean rotation rate $5 \Omega_{\odot}$ but a distinct differential rotation rate. The excitation of axisymmetric acoustic modes is further inhibited in the anti-solar differential rotation regime where the pole of stars rotates faster than their equator when compared to the uniform rotation case. This could hinder mode detection in such configurations. This study permits a first prediction of the excitation of acoustic modes as a function of the differential rotation in solar-like pulsators.