HD 147506b: A supermassive planet in an eccentric orbit transiting a bright star

G. Á Bakos, G. Kovács, G. Torres, D. A. Fischer, D. W. Latham, R. W. Noyes, D. D. Sasselov, T. Mazeh, A. Shporer, R. P. Butler, R. P. Stefanik, J. M. Fernández, A. Sozzetti, A. Pal, J. Johnson, G. W. Marcy, J. N. Winn, B. Sipöcz, J. Lázár, I. PappP. Sári

Research output: Contribution to journalArticlepeer-review

155 Scopus citations


We report the discovery of a massive (Mp, = 9.04 ±0.50 MJ) planet transiting the bright (V = 8.7) F8 star HD 147506, with an orbital period of 5.63341 ±0.00013 days and an eccentricity of e = 0.520 ±0.010. From the transit light curve we determine that the radius of the planet is Rp = 0.982-0.105+0.038 R J. HD 147506b (also coined HAT-P-2b) has a mass about 9 times the average mass of previously known transiting exoplanets and a density of ρρ ≈12 g cm-3, greater than that of rocky planets like the Earth. Its mass and radius are marginally consistent with theories of structure of massive giant planets composed of pure H and He, and accounting for them may require a large (≳100 M) core. The high eccentricity causes a ninefold variation of insolation of the planet between peri- and apastron. Using follow-up photometry, we find that the center of transit is Tmid = 2,454,212.8559 ± 0.0007 ( HJD) and the transit duration is 0.177 ± 0.002 days.

Original languageEnglish (US)
Pages (from-to)826-832
Number of pages7
JournalAstrophysical Journal
Issue number1
StatePublished - Nov 20 2007
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Planetary systems
  • Stars: individual (HD 147506)


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