Styliani (Stella) Kafka joined DTM this month after completing her Ph.D. in Astronomy at Indiana University. Her research focuses on studying the characteristics and evolution of magnetic activity and activity cycles in fast-rotating lower-main-sequence M dwarfs. She is particularly interested in the possible effect a close companion star has on the activity levels of these stars. Such close binaries are abundant—ranging from detached and semi-detached systems to M-dwarf-exoplanet binaries, including tidally locked binary variables, known as cataclysmic variables (CVs).

As part of her Ph.D. thesis, Kafka explored methods to assess magnetic activity on low-mass main-sequence donor stars in CVs at times of negligible accretion. Using multi-epoch, time-resolved photometry and spectroscopy, she provided the first direct detection of “hyperactivity” on those stars in the form of magnetic loops. Her present sample indicates that such activity structures are characteristic of all CV donor stars, although their formation mechanism and consequences on the system’s evolution remain unexplained.

At DTM, Kafka plans on investigating how this M dwarf hyperactivity affects a star’s habitable zone. Using the DuPont and Magellan telescopes, she will study the effect of a host star’s flux variations during activity cycles on a star’s habitable zone and on planets’ biosignatures, assessing the habitability of planets in those zones.