Stellar Contamination in Exoplanet Transmission Spectra

该项目的目的是限制恒星不均匀性对系外行星透射光谱的污染（即，斑点和光斑），以便能够更准确地进行系外行星大气反演。开始，恒星大气的磁流体动力学模拟的正向建模将与不同的平均磁场和不同的光谱类型。每个模拟的斑点和光斑的覆盖分数和对比度将使污染水平得以了解。这些模拟还将探讨光斑和光斑出现的活跃纬度不同对污染程度的影响。然后将对标准系外行星过境每个恒星模拟的模拟过境数据进行大气检索。这将允许已知污染对每个导出的透射光谱的影响被约束为不同的磁场强度和恒星光谱类型。调查结果将应用于真实的过境数据。

The purpose of the project is to constrain the contamination of exoplanet transmission spectra from stellar inhomogeneities (i.e., spots and faculae) in order that exoplanet atmospheric retrievals can be performed with greater accuracy. To begin, forward modelling of stellar atmospheres with magneto-hydrodynamic simulations will be done with a varying mean magnetic field and for different spectral types. The covering fraction and contrasts of the spots and faculae for each simulation will enable the contamination level to be known. The simulations will also explore the effect of having different active latitudes for spot and faculae emergence on the degree of contamination. Atmospheric retrievals will then be done to simulated transit data for a standard exoplanet transiting each of the stellar simulations. This will allow the effect of the known contamination on each of the derived transmission spectra to be constrained for varying magnetic field strength and stellar spectral type. The findings from this investigation will then be applied to real transit data.