The GAPS programme with HARPS-N at TNG: VI. The curious case of TrES-4b

A. Sozzetti, A. S. Bonomo, K. Biazzo, L. Mancini, M. Damasso, S. Desidera, R. Gratton, A. F. Lanza, E. Poretti, M. Rainer, L. Malavolta, L. Affer, M. Barbieri, L. R. Bedin, C. Boccato, M. Bonavita, F. Borsa, S. Ciceri, R. U. Claudi, D. GandolfiP. Giacobbe, T. Henning, C. Knapic, D. W. Latham, G. Lodato, A. Maggio, J. Maldonado, F. Marzari, A. F. Martinez Fiorenzano, G. Micela, E. Molinari, C. Mordasini, V. Nascimbeni, I. Pagano, M. Pedani, F. Pepe, G. Piotto, N. Santos, G. Scandariato, E. Shkolnik, J. Southworth

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


We update the TrES-4 system parameters using high-precision HARPS-N radial-velocity measurements and new photometric light curves. A combined spectroscopic and photometric analysis allows us to determine a spectroscopic orbit with a semi-amplitude K = 51 ± 3 ± s-1. The derived mass of TrES-4b is found to be Mp = 0.49 ± 0.04 MJup, significantly lower than previously reported. Combined with the large radius (Rp = 1.84+0.08-0.09 RJup) inferred from our analysis, TrES-4b becomes the transiting hot Jupiter with the second-lowest density known. We discuss several scenarios to explain the puzzling discrepancy in the mass of TrES-4b in the context of the exotic class of highly inflated transiting giant planets.

Original languageEnglish (US)
Article numberL15
JournalAstronomy and Astrophysics
StatePublished - Mar 2015
Externally publishedYes


  • Planetary systems
  • Stars: individual: TrES-4b
  • Techniques: photometric
  • Techniques: radial velocities
  • Techniques: spectroscopic

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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