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arXiv · 1304.2140

HATS-2b: A transiting extrasolar planet orbiting a K-type star showing starspot activity

M. Mohler-Fischer·L. Mancini·J. D. Hartman·G. B. Bakos·K. Penev·D. Bayliss·A. Jordan·Z. Csubry·G. Zhou·M. Rabus·N. Nikolov·R. Brahm·N. Espinoza·L. A. Buchhave·B. Beky·V. Suc·B. Csak·T. Henning·D. J. Wright·C. G. Tinney·B. C. Addison·B. Schmidt·R. W. Noyes·I. Papp·J. Lazar·P. Sari·P. Conroy
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Abstract

We report the discovery of HATS-2b, the second transiting extrasolar planet detected by the HATSouth survey. HATS-2b is moving on a circular orbit around a V=13.6 mag, K-type dwarf star (GSC 6665-00236), at a separation of 0.0230 \pm 0.0003 AU and with a period of 1.3541 days. The planetary parameters have been robustly determined using a simultaneous fit of the HATSouth, MPG/ESO~2.2\,m/GROND, Faulkes Telescope South/Spectral transit photometry and MPG/ESO~2.2\,m/FEROS, Euler~1.2\,m/CORALIE, AAT~3.9\,m/CYCLOPS radial-velocity measurements. HATS-2b has a mass of 1.37 \pm 0.16 M_J, a radius of 1.14 \pm 0.03 R_J and an equilibrium temperature of 1567 \pm 30 K. The host star has a mass of 0.88 \pm 0.04 M_Sun, radius of 0.89 \pm 0.02 R_Sun and shows starspot activity. We characterized the stellar activity by analysing two photometric follow-up transit light curves taken with the GROND instrument, both obtained simultaneously in four optical bands (covering the wavelength range of 3860-9520 \AA). The two light curves contain anomalies compatible with starspots on the photosphere of the parent star along the same transit chord.

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M. Mohler-Fischer, L. Mancini, J. D. Hartman, G. B. Bakos, K. Penev, D. Bayliss, A. Jordan, Z. Csubry, G. Zhou, M. Rabus, N. Nikolov, R. Brahm, N. Espinoza, L. A. Buchhave, B. Beky, V. Suc, B. Csak, T. Henning, D. J. Wright, C. G. Tinney, B. C. Addison, B. Schmidt, R. W. Noyes, I. Papp, J. Lazar, P. Sari, P. Conroy. 2013-04-08. HATS-2b: A transiting extrasolar planet orbiting a K-type star showing starspot activity. https://doi.org/10.1051/0004-6361/201321663

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