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Group members

My research group, in the lingo of my institute, is called a “research section” with the name Stellar Physics and Exoplanets, and it includes an embedded “research group” with the name Stellar Activity which is led by my senior scientist Sydney Barnes. The current group members are:

Senior scientists:

  • Prof. Dr. Katja Poppenhaeger (head of Stellar Physics and Exoplanets); star-exoplanet systems, stellar magnetic activity, exoplanetary atmospheres, young stars, coronae
  • Dr. Julián Alvarado-Gómez; observations and simulations of stellar coronal mass ejections, exoplanet atmospheres
  • Dr. Sydney Barnes (head of embedded group Stellar Activity); gyrochronology, stellar clusters
  • Dr. Thorsten Carroll; Doppler Imaging, Zeeman Doppler Imaging
  • Dr. Silva Järvinen; magnetism of cool and hot stars (staff astronomer; ANDES-UBV instrument scientist)
  • Dr. Matthias Steffen; stellar chromospheres, simulations (retired/guest)


  • Dr. Eliana Amazo Gomez; stellar magnetism and rotation
  • Dr. Nikoleta Ilic; star-planet interactions
  • Dr. David Gruner (with Barnes); gyrochronology

PhD students:

  • Desmond Dsouza; stellar activity, binary systems
  • Judy Chebly; simulations of stellar winds in star-exoplanet systems
  • Yu Xu (visiting PhD student); coronal mass ejections
  • Özgün Adebali (with Barnes); stellar binary systems

Master and Bachelor students:

  • Cole Kilby (master student); machine learning and exoplanet spectroscopy
  • Cinta Vidante (master student); flares of young M dwarfs

Completed theses

  • “The impact of stellar activity evolution on atmospheric mass loss of young exoplanets”, PhD thesis, Laura Ketzer, U Potsdam, 2024
  • “Evolutionary scatter of magnetic activity in cool star twins”, Master thesis, Desmond Dsouza, U Potsdam, 2023
  • “Stars under influence: evidence of tidal interactions between stars and substellar companions”, PhD thesis, Nikoleta Ilic, U Potsdam, 2023
  • “Spectral features of Earth’s Atmosphere in Observations”, Master thesis, Joana Wokittel, FU Berlin, 2023
  • “Analysis of facular to spot ratio of sun-like stars using Gradient of Power Spectra (GPS) method”, Master thesis, Prachi Rahate, U Potsdam, 2023
  • “Clarifying the discrepant results in the characterization of exoplanetary atmospheres”, PhD thesis (with Strassmeier), Xanthippi Alexoudi, U Potsdam, 2023
  • “High lights: stellar flares as probes of magnetism in stars and star-planet systems”, PhD thesis, Ekaterina Ilin, U Potsdam, 2022
  • “X-ray studies of exoplanet systems”, PhD thesis, Grace Foster, U Potsdam, 2022
  • “Bestimmung der Bahnverkippung der Muttersterne exosolarer heißer Gasplaneten”, Bachelor thesis, Julia Schötzig, TU Wildau, 2022
  • “From fast to slow rotation in the open clusters NGC 2516 and NGC 3532”, PhD thesis (with Barnes), Dario Fritzewski, U Potsdam, 2021
  • “Atmospheric properties and dynamics of gaseous exoplanets inferred from high-resolution alkali line transmission spectroscopy”, PhD thesis (with Strassmeier), Engin Keles, U Potsdam, 2021
  • “Are there clouds on Ultra Hot Jupiters?”, Master thesis, Alexandra Gillet, U Potsdam, 2021
  • “Transits in the young system PTFO 8-8695, is there a planet?”, Master thesis, Marzie Hosseini, U Potsdam, 2021
  • “The properties of transiting exoplanets”, PhD thesis, Rob Wells, Queen’s University Belfast, 2019
  • “The magnetic activity evolution of main sequence cool stars”, PhD thesis, Rachel Booth, Queen’s University Belfast, 2019

Former long-term group members

  • Dr. Ekaterina Ilin (PhD, postdoc, now at ASTRON / Vedantham’s group); low-mass stars, flares, star-planet systems
  • Dr. Engin Keles (PhD, postdoc, now at TU Berlin / Noack’s group); exoplanet high-resolution transmission spectroscopy
  • Dr. Matthias Mallonn (postdoc, now at Forschungsträger Jülich); exoplanet photometry and spectroscopy
  • Dr. Andy Gallagher (postdoc with Steffen, now in industry); stellar atmospheres and abundances
  • Dr. Grace Foster (PhD, now in data science); X-ray studies of exoplanet systems
  • Dr. Xanthippi Alexoudi (PhD with Strassmeier); transit observations of exoplanets
  • Dr. Laura Ketzer (PhD, now in professional sports); evaporation of young exoplanets
  • Dr. Elisabeth Cole-Kodikara (postdoc with Barnes, now at ANU / Krumholz’s group); stellar clusters
  • Dr. Dario Fritzewski (PhD, postdoc with Barnes, now at KU Leuven / Aerts’ group); stellar clusters

Talks by special guests

  • Mar. 2024: Dr. Kristina Monsch on evolution of protoplanetary disks
  • Jan. 2023: Marcus Marcussen and Prof. Dr. Simon Albrecht on exoplanets in perpendicular orbits
  • Feb. 2022: Victoria diTomasso on exoplanet projects and the graduate student experience in the US
  • Feb. 2020: Prof. Dr. Carolina von Essen on TESS light curve studies of exoplanet host stars
  • Nov. 2019: Dr. Vera Dobos on tidal heating of exomoons