eRASSUCDs

Ein neues Fenster zur magnetischen Aktivität auf Ultrakühlen Zwergen: eROSITA in Synergie mit Multiwellenlaengenbeobachtungen

01.01.2022 bis 31.12.2024

Ultracool dwarfs (UCDs) are defined as objects with spectral type M7 and later. The advent of the (nearly) all-sky space missions eROSITA and TESS opens a new window to UCDs, providing for the first time statistical samples of coronal X-ray emission and photospheric optical activity measures and surface rotation periods. eROSITA will increase the number of X-ray detected UCDs by at least a factor of 10, and it will enable a systematic study of flare variability thanks to its multi-epoch data (8 visits over 4 years). TESS provides optical flares and rotation periods that – according to previous studies – appear to be crucial for determining the type of activity in UCDs. This will be complemented by an in-depth study of UCDs for which the applicant of this funding request has collected multi-wavelength observations of all critical parameters for activity (X-rays, radio and rotation).