晚型活动星的散射线偏振
Scattering linear polarization of late-type active stars
摘要：
许多活跃的恒星被斑点覆盖，比太阳更多，这是由光谱和光度观测所表明的。据预测，恒星黑子通过破坏可见星盘的对称性而引起非零的内禀线偏振。虽然很小，这种影响可能是有用的星点研究，这是特别重要的未来偏振大气层的特征外行星轨道活跃的宿主恒星。使用模型的中心到边缘的强度和偏振的连续散射的存在下，并采用一个简化的双温度光球模型，我们的目标是估计的内禀线性偏振晚型恒星的不同重力，有效温度，和斑点。我们开发了一个代码，模拟各种斑点配置或使用任意的表面映射，进行数值磁盘积分，并建立斯托克斯参数相位曲线的恒星在一个旋转周期为选定的波长。它允许估计最小和最大偏振值为一组给定的恒星参数和现场覆盖。在假设光球-光斑温度差和光斑尺寸分布的基础上，利用平行平面和球形大气模型，计算了$T_{\rm eff}$ = 3500 K - 6000 K，log $g$ = 1.0 - 5.0的晚型恒星的线偏振。采用随机光斑表面分布，分析了光斑覆盖率与偏振态的关系，确定了不同输入参数对结果的影响。此外，我们认为点配置与极地点和活跃的纬度和赤道。
英文摘要：
Many active stars are covered in spots, much more so than the Sun, as indicated by spectroscopic and photometric observations. It has been predicted that star spots induce non-zero intrinsic linear polarization by breaking the visible stellar disk symmetry. Although small, this effect might be useful for star spot studies, and it is particularly significant for a future polarimetric atmosphere characterization of exoplanets orbiting active host stars. Using models for a center-to-limb variation of the intensity and polarization in presence of continuum scattering and adopting a simplified two-temperature photosphere model, we aim to estimate the intrinsic linear polarization for late-type stars of different gravity, effective temperature, and spottedness. We developed a code that simulates various spot configurations or uses arbitrary surface maps, performs numerical disk integration, and builds Stokes parameter phase curves for a star over a rotation period for a selected wavelength. It allows estimating minimum and maximum polarization values for a given set of stellar parameters and spot coverages. Based on assumptions about photosphere-to-spot temperature contrasts and spot size distributions, we calculate the linear polarization for late-type stars with $T_{\rm eff}$ = 3500 K - 6000 K, log$g$ = 1.0 - 5.0, using the plane-parallel and spherical atmosphere models. Employing random spot surface distribution, we analyze the relation between spot coverage and polarization and determine the influence of different input parameters on results. Furthermore, we consider spot configurations with polar spots and active latitudes and longitudes.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
