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arXiv · 1004.1514

WASP-22 b: A transiting "hot Jupiter" planet in a hierarchical triple system

P. F. L. Maxted·D. R. Anderson·M. Gillon·C. Hellier·D. Queloz·B. Smalley·A. H. M. J. Triaud·R. G. West·D. M. Wilson·S. J. Bentley·H. Cegla·A. Collier Cameron·B. Enoch·L. Hebb·K. Horne·J. Irwin·T. A. Lister·M. Mayor·N. Parley·F. Pepe·D. Pollacco·D. Segransan·S. Udry·P. J. Wheatley
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Abstract

We report the discovery of a transiting planet orbiting the star TYC 6446-326-1. The star, WASP-22, is a moderately bright (V=12.0) solar-type star (Teff = 6000 +/- 100 K, [Fe/H] = -0.05 +/- 0.08). The lightcurve of the star obtained with the WASP-South instrument shows periodic transit-like features with a depth of about 1 and a duration of 0.14 days. The presence of a transit-like feature in the lightcurve is confirmed using z-band photometry obtained with Faulkes Telescope South. High resolution spectroscopy obtained with the CORALIE and HARPS spectrographs confirm the presence of a planetary mass companion with an orbital period of 3.533 days in a near-circular orbit. From a combined analysis of the spectroscopic and photometric data assuming that the star is a typical main-sequence star we estimate that the planet has a mass M_p = 0.56 +/- 0.02 M_Jup and a radius R_p = 1.12 +/- 0.04 R_Jup. In addition, there is a linear trend of 40 m/s/yr in the radial velocities measured over 16 months, from which we infer the presence of a third body with a long period orbit in this system. The companion may be a low mass M-dwarf, a white dwarf or a second planet.

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P. F. L. Maxted, D. R. Anderson, M. Gillon, C. Hellier, D. Queloz, B. Smalley, A. H. M. J. Triaud, R. G. West, D. M. Wilson, S. J. Bentley, H. Cegla, A. Collier Cameron, B. Enoch, L. Hebb, K. Horne, J. Irwin, T. A. Lister, M. Mayor, N. Parley, F. Pepe, D. Pollacco, D. Segransan, S. Udry, P. J. Wheatley. 2010-10-12. WASP-22 b: A transiting "hot Jupiter" planet in a hierarchical triple system. https://doi.org/10.1088/0004-6256%2F140%2F6%2F2007

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