Investigating the Effects of Spots on Stellar Spectra
Author: Claire Komori
Faculty Supervisor: John. M. Brewer
Department: Physics & Astronomy
We present the results of comparative analyses of sunspot spectra with local thermodynamic equilibrium (LTE) spectral models constructed through forward modeling using Spectroscopy Made Easy. Correct interpretations of stellar spectra are crucial for accurately deriving stellar information. However, active regions of stars such as starspots can alter the light that we receive. It is not clearly understood, how active regions in stars affect the shapes of spectral lines when assuming LTE. In this study, we analyze sunspot spectra in the visible to investigate whether its spectral lines can be reproduced with a model that assumes solar parameters with cooler surface temperature. Our results show that the symmetric line shapes of LTE models do not adequately capture the spectral line shape variations that are induced by active regions. Therefore, to compute realistic spectral line profiles and derive unbiased stellar parameters from possible spotted stars, models will require improvement that takes into account the non-LTE line formation effects of starspots.