Séminaire IPAG

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A physics-based model of stellar activity for exoplanet detection

jeudi 26 mars 2026 - 11h00

Nathan Hara - LAM
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To detect small exoplanets with photometry and radial velocities, it is essential to estimate the contribution of stellar signals. In particular, magnetic activity creates signals whose amplitude exceeds that of terrestrial planets in the habitable zone. Modelling activity signals precisely is critical, yet existing models are based on qualitative considerations. In this talk, I will present a way to build a computationally efficient model of stellar activity signals from physical hypotheses. Besides exoplanet detection, the new models have two applications. First, we will see that they allow to perform statistical Doppler imaging retrieving the average properties of magnetic regions even if their signal is too small to be resolved individually. I will show in particular that the inclination of the Sun can be estimated based on photometric and radial velocity observations only. Second, I will show that the statistical framework of a flexible class of models to represent complex, correlated noises.

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Hôtes : Alexandre Santerne

Salle Manuel Forestini, 414 rue de la piscine, 38400 Saint Martin d'Hères