WASP-12b: The hottest transiting extrasolar planet yet discovered

L. Hebb, A. Collier-Cameron, B. Loeillet, D. Pollacco, G. Hébrard, R. A. Street, F. Bouchy, H. C. Stempels, C. Moutou, E. Simpson, S. Udry, Y. C. Joshi, R. G. West, I. Skillen, D. M. Wilson, I. McDonald, N. P. Gibson, S. Aigrain, D. R. Anderson, C. R. BennD. J. Christian, B. Enoch, C. A. Haswell, C. Hellier, K. Horne, J. Irwin, T. A. Lister, P. Maxted, M. Mayor, A. J. Norton, N. Parley, F. Pont, D. Queloz, B. Smalley, P. J. Wheatley

Research output: Contribution to journalArticle

226 Citations (Scopus)


We report on the discovery of WASP-12b, a new transiting extrasolar planet with Rpl = 1.79 -0.09 +0.09RJ and Mpl = 1.41-0.10 +0.10 MJ. The planet and host star properties were derived from a Monte Carlo Markov chain analysis of the transit photometry and radial velocity data. Furthermore, by comparing the stellar spectrum with theoretical spectra and stellar evolution models, we determined that the host star is a supersolar metallicity ([M/H]= 0.3 -0.15 +0.05), late-F (Teff = 6300 -100 +200 K) star which is evolving off the zero-age main sequence. The planet has an equilibrium temperature of Teq = 2516 K caused by its very short period orbit (P = 1.09 days) around the hot, twelfth magnitude host star. WASP-12b has the largest radius of any transiting planet yet detected. It is also the most heavily irradiated and the shortest period planet in the literature.

Original languageEnglish
Pages (from-to)1920-1928
Number of pages9
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 10 Mar 2009
Externally publishedYes



  • Planetary systems
  • Techniques: photometric
  • Techniques: radial velocities

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Hebb, L., Collier-Cameron, A., Loeillet, B., Pollacco, D., Hébrard, G., Street, R. A., Bouchy, F., Stempels, H. C., Moutou, C., Simpson, E., Udry, S., Joshi, Y. C., West, R. G., Skillen, I., Wilson, D. M., McDonald, I., Gibson, N. P., Aigrain, S., Anderson, D. R., ... Wheatley, P. J. (2009). WASP-12b: The hottest transiting extrasolar planet yet discovered. Astrophysical Journal, 693(2), 1920-1928. https://doi.org/10.1088/0004-637X/693/2/1920