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

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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
Pages (from-to)826-832
Number of pages7
JournalAstrophysical Journal
Issue number1
Publication statusPublished - Nov 20 2007



  • Planetary systems
  • Stars: individual (HD 147506)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Bakos, G. Á., Kovács, G., Torres, G., Fischer, D. A., Latham, D. W., Noyes, R. W., Sasselov, D. D., Mazeh, T., Shporer, A., Butler, R. P., Stefanik, R. P., Fernández, J. M., Sozzetti, A., Pal, A., Johnson, J., Marcy, G. W., Winn, J. N., Sipöcz, B., Lázár, J., ... Sári, P. (2007). HD 147506b: A supermassive planet in an eccentric orbit transiting a bright star. Astrophysical Journal, 670(1), 826-832. https://doi.org/10.1086/521866