English

Transit mapping of a starspot on CoRoT-2 - Probing a stellar surface by planetary transits

Solar and Stellar Astrophysics 2015-05-13 v1

Abstract

We analyze variations in the transit lightcurves of CoRoT-2b, a massive hot Jupiter orbiting a highly active G star. We use one transit lightcurve to eclipse-map a photospheric spot occulted by the planet. In this case study we determine the size and longitude of the eclipsed portion of the starspot and systematically study the corresponding uncertainties. We determine a spot radius between 4.5\degr4.5\degr and 10.5\degr10.5\degr on the stellar surface and the spot longitude with a precision of about ±1\pm 1 degree. Given the well-known transit geometry of the CoRoT-2 system, this implies a reliable detection of spots on latitudes typically covered by sunspots; also regarding its size the modelled spot is comparable to large spot groups on the Sun. We discuss the future potential of eclipse mapping by planetary transits for the high-resolution analysis of stellar surface features.

Keywords

Cite

@article{arxiv.0906.4140,
  title  = {Transit mapping of a starspot on CoRoT-2 - Probing a stellar surface by planetary transits},
  author = {U. Wolter and J. H. M. M. Schmitt and K. F. Huber and S. Czesla and H. M. Mueller and E. W. Guenther and A. P. Hatzes},
  journal= {arXiv preprint arXiv:0906.4140},
  year   = {2015}
}

Comments

accepted by Astronomy and Astrophysics