Seminar: Stellar limb darkening for JWST spectroscopic light curves: theory vs. data

Stellar limb-darkening controls the depth and shape of every transit light curve. Accurate knowledge of limb darkening is essential when measuring the orbital, atmospheric, and bulk properties of transiting exoplanets. Prior to JWST, empirical tests of stellar limb darkening focused mainly on broadband photometric time series (e.g., Kepler, TESS). Now with very precise spectroscopic light curves from JWST, we have the opportunity and a strong need to test models of limb darkening.

I will compare limb-darkening measurements obtained by fitting JWST spectroscopic observations (0.6-5.3 µm) of exoplanet transits with theoretical limb darkening predicted by various stellar atmosphere models, including a 3D MHD model (MURaM + MPS-ATLAS) with various magnetic field strengths. I will show results for a sequence of spectral types (G0, K1, M4), noting differences between predicted and measured limb darkening. I will discuss how limb darkening parameterization and analysis choices can impact limb darkening measurements.

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We shall leave for lunch at around 12:15. There might be fika after the seminar.