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formerly Baltic Astronomy

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Volume 26, Issue 1


News From The Erebos Project

Veronika Schaffenroth
  • Corresponding author
  • Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, 72076 Tübingen, Germany
  • Institute for Astro- and Particle Physics, University of Innsbruck, Technikerstr. 25/8, 6020 Innsbruck, Austria
  • Email
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Brad Barlow / Stephan Geier
  • Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, 72076 Tübingen, Germany
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Maja Vučković
  • Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Playa Ancha, Valparaíso 2360102, Chile
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Dave Kilkenny
  • Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Johannes Schaffenroth
  • Dr. Remeis-Observatory & ECAP, Astronomical Institute, Friedrich-Alexander University Erlangen-Nürnberg, Sternwartstr. 7, 96049 Bamberg, Germany
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2017-12-29 | DOI: https://doi.org/10.1515/astro-2017-0438


Planets and brown dwarfs in close orbits will interact with their host stars, as soon as the stars evolve to become red giants. However, the outcome of those interactions is still unclear. Recently, several brown dwarfs have been discovered orbiting hot subdwarf stars at very short orbital periods of 0.065 - 0.096 d. More than 8% of the close hot subdwarf binaries might have sub-stellar companions. This shows that such companions can significantly affect late stellar evolution and that sdB binaries are ideal objects to study this influence. Thirty-eight new eclipsing sdB binary systems with cool low-mass companions and periods from 0.05 to 0.5 d were discovered based on their light curves by the OGLE project. In the recently published catalog of eclipsing binaries in the Galactic bulge, we discovered 75 more systems. We want to use this unique and homogeneously selected sample to derive the mass distribution of the companions, constrain the fraction of sub-stellar companions and determine the minimum mass needed to strip off the red-giant envelope. We are especially interested in testing models that predict hot Jupiter planets as possible companions. Therefore, we started the EREBOS (Eclipsing Reflection Effect Binaries from the OGLE Survey) project, which aims at analyzing those new HW Vir systems based on a spectroscopic and photometric follow up. For this we were granted an ESO Large Program for ESO-VLT/FORS2. Here we give an update on the the current status of the project and present some preliminary results.

Keywords : hot subdwarf stars; low-mass stellar companions; sub-stellar companions


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About the article

Received: 2017-09-30

Accepted: 2017-11-06

Published Online: 2017-12-29

Published in Print: 2017-12-20

Citation Information: Open Astronomy, Volume 26, Issue 1, Pages 208–213, ISSN (Online) 2543-6376, DOI: https://doi.org/10.1515/astro-2017-0438.

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