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 language | English |
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Pages (from-to) | 2007-2012 |
Number of pages | 6 |
Journal | The Astronomical Journal |
Volume | 140 |
DOIs | |
Publication status | Published - 1 Dec 2010 |
Keywords
- planetary systems