Modelling stellar variability

恒星变异性在恒星-行星相互作用中起着关键作用，也是系外行星描述中的一个令人讨厌的参数。该项目的目的是模拟恒星活动引起的恒星亮度的变化。我们将特别重视捕捉具有小尺度通量的活动区(“光斑”)的发射，因为这些区域的特征远不如恒星黑子。由于光斑没有被分解，我们将使用从磁对流的辐射传输计算中得到的模型光谱。这将使我们能够从行星凌日光谱中去除恒星活动的污染。

Stellar variability plays a key part in star-planet interactions and is a nuisance parameter in exoplanet characterisation. The aim of the project is to model changes in the stellar brightness due to stellar activity. We will put particular emphasis in capturing the emission from active regions with small-scale flux (`faculae') as these are much less well characterised than starspots. As faculae are not resolved, we will be using model spectra derived from radiative transfer calculations of magneto-convection. This will allow us to remove stellar-activity contamination from planet transit spectra.