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. PepeD. Pollacco, D. Segransan, S. Udry, P.~J. Wheatley

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23 Citations (Scopus)

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 (T$_eff$ = 6000 plusmn 100 K, [Fe/H] = -0.05 plusmn 0.08). The light curve 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 light curve is confirmed using z-band photometry obtained with Faulkes Telescope South. High-resolution spectroscopy obtained with the CORALIE and HARPS spectrographs confirms 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 plusmn 0.02M $_Jup$ and a radius R $_p$ = 1.12 plusmn 0.04R $_Jup$. In addition, there is a linear trend of 40 m s$^-1$ yr$^-1$ 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.
Original languageEnglish
Pages (from-to)2007-2012
Number of pages6
JournalThe Astronomical Journal
Volume140
DOIs
Publication statusPublished - 1 Dec 2010

Keywords

  • planetary systems

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