Contributed Talk - Splinter Exoplanets

Friday, 17 September 2021, 16:30   (virtual Exo)

Using direct flare localization to understand exo-space weather and stellar magnetic fields

Ekaterina Ilin (1,2), Katja Poppenhäger (1,2), Sarah J. Schmidt (1), Silva P. Järvinen (1), Elisabeth R. Newton (3), Julián D. Alvarado-Gómez (1), J. Sebastian Pineda (4), James R. A. Davenport (5), Mahmoudreza Oshagh (6,7), Ilya Ilyin (1)
(1) Leibniz Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany (2) Institute for Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany (3) Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755, USA (4) University of Colorado Boulder, Laboratory for Atmospheric and Space Physics, 3665 Discovery Drive, Boulder CO, 80303, USA (5) Department of Astronomy, University of Washington, Seattle, WA 98195, USA (6) Instituto de Astrofísica de Canarias (IAC), 38205 La Laguna, Tenerife, Spain (7) Departamento de Astrofísica, Universidad de La Laguna (ULL), 38206, La Laguna, Tenerife, Spain

Stars are uniform spheres, but only to first order. The way in which stellar rotation and magnetism break this symmetry places important observational constraints on stellar magnetic fields, and factors in the assessment of the impact of stellar activity on exoplanets. The spatial distribution of flares on the solar surface is well known to be non-uniform, but it is elusive on other stars. There are several indirect ways to localize flares on the stellar surface. In this talk, I will briefly review them, and introduce a new direct method that enables systematic flare localization directly from optical light curves. The results obtained by applying the new method to light curves taken by the Transiting Exoplanet Survey Satellite are evidence that actively flaring regions emerge much closer to the rotational poles of fully convective stars than on the Sun. This may reduce the impact that stellar activity has on the habitability of exoplanets that orbit those stars in the equatorial plane.