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You are here: FRIAS Fellows Fellows 2019/20 Dr. rer. nat. Stefanie Rätz

Dr. rer. nat. Stefanie Rätz

Albert-Ludwigs-Universität Freiburg
Astronomy / Astrophysics
Junior Fellow (Marie S. Curie FCFP)
October 2016 - May 2017


Following a general interest in astronomy I started first astronomical observations already in basic school. I studied physics at the Friedrich-Schiller-University Jena and did my diploma and my PhD at the Astrophysical Institute and University Observatory Jena.
Today my main research field are transiting exoplanets in particular the search for transiting planets and the analysis of transit timing variations in already known transiting exoplanets. Additionally I'm also interested in the observations and analysis of variable stars especially eclipsing binaries. I'm involved in several research activities concerning the photometric observation of transiting planets and variable stars, including the search for transiting planets in young open clusters with the "Young Exoplanet Transit Initiative" (YETI), the observation of eclipsing binaries to search for eclipse timing variations within the "DWARF project" and the "Search for extrasolar planets by observations of transit timing variations" (TTV@YETI). I'm a very experienced observer. I observed >150 nights at the University Observatory Jena between 2006-2013, 15 nights at the 2.2 m telescope on Calar Alto, Spain between 2010-2012, and one night at the National Observatory Venezuela.
As a Research Fellow at the European Space Agency (ESA) I worked on the analysis of Transit Timing for the CoRoT planets and ground-based high precision follow-up photometry. I got involved in the Spectrograph for ESA's Optical Ground Station (OGS), a 1-m telescope at the Observatorio del Teide in Tenerife.

Selected Publications

  • Raetz, St., Schmidt, T.O.B., Czesla, S., et al. 2016, arXiv:1605.05091: "YETI observations of the young transiting planet candidate CVSO 30 b"

  • Schmidt, T.O.B., Neuhäuser, R., Briceno, C.,..., Raetz, St. et al. 2016, arXiv:1605.05315: "Direct Imaging discovery of a second planet candidate around the possibly transiting planet host CVSO 30"

  • Raetz, St., Maciejewski, G., Seeliger, M., et al. 2015, MNRAS, 451, 4139: "WASP-14 b: transit timing analysis of 19 light curves"

  • Raetz, St., Maciejewski, G., Ginski, C., et al. 2014, MNRAS, 444, 1351: "Transit timing of TrES-2: a combined analysis of ground- and space-based photometry"

  • Neuhäuser, R., Errmann, R., Berndt, A.,..., Raetz, St. et al. 2011, Astronomische Nachrichten, 332, 547: "The Young Exoplanet Transit Initiative (YETI)"

FRIAS Project

Variability and transiting extrasolar planets in young open clusters

So far only little is known about exoplanets during the first few millions of years  of their lives, and the goal is to fill the observational gap. Any detection of an exoplanet in  these young clusters would provide important constraints on planet formation and migration  time-scales and their relation to protoplanetary disc lifetimes.
Young open clusters provide an ideal environment for the search for young extrasolar planets,  since they feature a relatively large number of stars of the same known age and metallicity at  the same distance. In cooperation with the YETI (Neuhäuser et al. 2011) several 0.2 to 2.6 m telescopes around the world will be used to study one carefully selected young open clusters  (25 Ori, 7-10 Myr, 323 pc, Briceno  et al. 2007) mainly to detect young transiting planets and to  analyze variability phenomena on time-scales from minutes to years.
The light curves of young stars are dominated by stellar variability. In order to model any found transit event for a derivation of the planetary candidate properties, the effects of the stellar vari- ability in the light curves need to minimized. Therefore detailed studies of the variability will be carried out to characterize the young stars.
The project aims to provide a better understanding of the whole system especially their multi- plicity, physical variability and planetary companions.