WASP-22 b: A TRANSITING “HOT JUPITER” PLANET IN A HIERARCHICAL TRIPLE SYSTEM

• Published in: The Astronomical journal Vol. 140; no. 6; pp. 2007 - 2012
• Main Authors: Maxted, P. F. L., Anderson, D. R., Gillon, M., Hellier, C., Queloz, D., Smalley, B., Triaud, A. H. M. J., West, R. G., Wilson, D. M., Bentley, S. J., Cegla, H., Collier Cameron, A., Enoch, B., Hebb, L., Horne, K., Irwin, J., Lister, T. A., Mayor, M., Parley, N., Pepe, F., Pollacco, D., Segransan, D., Udry, S., Wheatley, P. J.
• Format: Journal Article Web Resource
• Language: English
• Published: United States Univ Chicago Press 01.12.2010
• Subjects: Astrophysics - Earth and Planetary Astrophysics; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Aérospatiale, astronomie & astrophysique; DWARF STARS; MAIN SEQUENCE STARS; MASS; ORBITS; PERIODICITY; PHOTOMETRY; Physical, chemical, mathematical & earth Sciences; Physique, chimie, mathématiques & sciences de la terre; planetary systems; PLANETS; RADIAL VELOCITY; Space science, astronomy & astrophysics; SPECTROSCOPY; STARS; TELESCOPES; VARIATIONS; VELOCITY; WHITE DWARF STARS
• ISSN: 0004-6256; 0004-637X; 1538-4357; 1538-3881; 1538-3881
• DOI: 10.1088/0004-6256/140/6/2007

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 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 ? 0.02M Jup and a radius R p = 1.12 ? 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.