HAT-P-24b: An inflated hot Jupiter on a 3.36 day period transiting a hot, metal-poor star

D. M. Kipping, G. Á Bakos, J. Hartman, G. Torres, A. Shporer, D. W. Latham, Géza Kovács, R. W. Noyes, A. W. Howard, D. A. Fischer, J. A. Johnson, G. W. Marcy, B. Béky, G. Perumpilly, G. A. Esquerdo, D. D. Sasselov, R. P. Stefanik, J. Lázár, I. Papp, P. Sári

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


We report the discovery of HAT-P-24b, a transiting extrasolar planet orbiting the moderately bright V = 11.818 F8 dwarf star GSC 0774-01441, with a period P = 3.3552464±0.0000071 days, transit epoch Tc = 2455216.97669±0.00024 (BJD)11, and transit duration 3.653±0.025 hr. The host star has a mass of 1.191±0.042M, radius of 1.317±0.068R, effective temperature 6373±80 K, and a low metallicity of [Fe/H] = -0.16±0.08. The planetary companion has a mass of 0.681±0.031 MJ and radius of 1.243±0.072 RJ yielding a mean density of 0.439±0.069 g cm-3. By repeating our global fits with different parameter sets, we have performed a critical investigation of the fitting techniques used for previous Hungarian-made Automated Telescope planetary discoveries. We find that the system properties are robust against the choice of priors. The effects of fixed versus fitted limb darkening are also examined. HAT-P-24b probably maintains a small eccentricity of e = 0.052-0.017+0.022, which is accepted over the circular orbit model with false alarm probability 5.8%. In the absence of eccentricity pumping, this result suggests that HAT-P- 24b experiences less tidal dissipation than Jupiter. Due to relatively rapid stellar rotation, we estimate that HAT-P-24b should exhibit one of the largest known Rossiter-McLaughlin effect amplitudes for an exoplanet (ΔVRM ≃ 95 m s-1) and thus a precise measurement of the sky-projected spin-orbit alignment should be possible.

Original languageEnglish (US)
Pages (from-to)2017-2028
Number of pages12
JournalAstrophysical Journal
Issue number2
StatePublished - Dec 20 2010
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Planetary systems
  • Stars: individual (HAT-P-24)
  • Techniques: photometric
  • Techniques: spectroscopic


Dive into the research topics of 'HAT-P-24b: An inflated hot Jupiter on a 3.36 day period transiting a hot, metal-poor star'. Together they form a unique fingerprint.

Cite this