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arXiv · 1501.06403

The GAPS Programme with HARPS-N@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. Gandolfi·P. 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
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Abstract

We revisit the TrES-4 system parameters based on 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 an amplitude $K=51\pm3$ m s$^{-1}$. The derived mass of TrES-4b is found to be $M_{\rm p} = 0.49\pm0.04 \rm M_{Jup}$, significantly lower than previously reported. Combined with the large radius ($R_{\rm p} = 1.84_{-0.09}^{+0.08} \rm R_{Jup}$) inferred from our analysis, TrES-4b becomes the second-lowest density transiting hot Jupiter 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.

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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. Gandolfi, P. 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. 2015-01-26. The GAPS Programme with HARPS-N@TNG VI: The Curious Case of TrES-4b. https://doi.org/10.1051/0004-6361%2F201425570

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