Hat-P-9b: A low-density planet transiting a moderately faint F star

Avi Shporer, Gáspár Á Bakos, Francois Bouchy, Frederic Pont, Géza Kovács, Dave W. Latham, Brigitta Sipöcz, Guillermo Torres, Tsevi Mazeh, Gilbert A. Esquerdo, András Pál, Robert W. Noyes, Dimitar D. Sasselov, József Lázár, István Papp, Pál Sári, Gábor Kovács

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37 Citations (Scopus)


We report the discovery of a planet transiting a moderately faint (V = 12.3 mag) late F star, with an orbital period of 3.92289 ± 0.00004 days. From the transit light curve and radial velocity measurements, we determine that the radius of the planet is Rp = 1.40 ± 0.06 R Jup and that the mass is Mp = 0.78 ± 0.09 M Jup. The density of the new planet, ρp = 0.35 ± 0.06 g cm -3, fits to the low-density tail of the currently known transiting planets. We find that the center of transit is at T c = 2454417.9077 ± 0.0003 (HJD), and the total transit duration is 0.143 ± 0.004 days. The host star has M = 1.28 ± 0.13 M and R = 1.32 ± 0.07 R .

Original languageEnglish
Pages (from-to)1393-1400
Number of pages8
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 2009


  • Planetary systems
  • Stars: individual (GSC 02463 - 00281, HAT-P-9)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Shporer, A., Bakos, G. Á., Bouchy, F., Pont, F., Kovács, G., Latham, D. W., Sipöcz, B., Torres, G., Mazeh, T., Esquerdo, G. A., Pál, A., Noyes, R. W., Sasselov, D. D., Lázár, J., Papp, I., Sári, P., & Kovács, G. (2009). Hat-P-9b: A low-density planet transiting a moderately faint F star. Astrophysical Journal, 690(2), 1393-1400. https://doi.org/10.1088/0004-637X/690/2/1393