Seminars at MPS

Interested visitors are very welcome to join in all seminars held and talks given at the MPS. The presentations are mainly given in English. More detailed information can be found at the seminars' pages. Invited guest scientists of other institutes report on the successes and results of their research in institute seminars and colloquia. PhD students of the International Max Planck Research School (IMPRS) present their work in S3 seminars. In the Seminars about Planets and Comets, as well as in the Seminars about the Sun and sunlike Stars, the scientists of the respective departments report on the latest results and progress made in their projects and introduce new missions. All seminars are concluded with a short discussion or a questions-and-answers sessions.

A picture of a part of the limb of the Sun with a large protuberance towering above the surface to the left of the limb

SSGS: Stellar surface magnetic field: Effects on Limb Darkening and Granulation Flicker (Nadiia Kostogryz)

Solar and Stellar Group Seminar

Date: Sep 8, 2026
Time: 11:00 AM - 12:00 PM (Local Time Germany)
Speaker: Nadiia Kostogryz
MPS
Location: Max-Planck-Institut für Sonnensystemforschung
Room: Auditorium
Host: Robert Cameron

Magnetic fields shape the surfaces of cool stars, even when the star appears photometrically quiet. In this seminar, I will discuss how small-scale surface magnetism affects two key stellar signals relevant for exoplanet and stellar studies: limb darkening and granulation-driven brightness variability, or flicker. Using 3D radiative magnetohydrodynamic simulations with MURaM, combined with spectral synthesis using MPS-ATLAS, we investigate how magnetic fields modify the center-to-limb intensity variation and the wavelength dependence of flicker. I will show that magnetic flux concentrations can make limb darkening shallower, alter the spectral shape of flicker, and introduce wavelength-dependent stellar signals that may affect transit and transmission-spectroscopy analyses. These results highlight the need to include realistic magnetic stellar atmospheres when interpreting high-precision observations from Kepler, TESS, JWST, and PLATO. [more]