| Issue |
A&A
Volume 575, March 2015
|
|
|---|---|---|
| Article Number | L15 | |
| Number of page(s) | 10 | |
| Section | Letters | |
| DOI | https://doi.org/10.1051/0004-6361/201425570 | |
| Published online | 05 March 2015 | |
The GAPS programme with HARPS-N at TNG
VI. The curious case of TrES-4b⋆,⋆⋆
1 INAF–Osservatorio Astrofisico di Torino, via Osservatorio 20, 10025 Pino Torinese, Italy
e-mail: sozzetti@oato.inaf.it
2 INAF–Osservatorio Astrofisico di Catania, via S.Sofia 78, 95123 Catania, Italy
3 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
4 INAF–Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, 35122 Padova, Italy
5 INAF–Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate (LC), Italy
6 INAF–Osservatorio Astronomico di Palermo, Piazza del Parlamento, Italy 1, 90134 Palermo, Italy
7 Landessternwarte Königstuhl, Zentrum für Astronomie der Universitat Heidelberg, Königstuhl 12, 69117 Heidelberg, Germany
8 INAF–Osservatorio Astronomico di Trieste, via Tiepolo 11, 34143 Trieste, Italy
9 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts, 02138, USA
10 Dipartimento di Fisica, Università di Milano, via Celoria 16, 20133 Milano, Italy
11 Dip. di Fisica e Astronomia Galileo Galilei–Università di Padova, Vicolo dell’Osservatorio 2, 35122 Padova, Italy
12 Fundación Galileo Galilei – INAF, Rambla José Ana Fernandez Pérez 7, 38712 Breña Baja, TF, Spain
13 INAF–IASF Milano, via Bassini 15, 20133 Milano, Italy
14 Département d’Astronomie de l’Université de Genève, 51 ch. des Maillettes – Observatoire de Sauverny, 1290 Versoix, Switzerland
15 Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
16 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
17 Lowell Observatory, 1400 W. Mars Hill Road, Flagstaff, AZ 86001, USA
18 Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
Received: 22 December 2014
Accepted: 19 January 2015
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 m 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 = 1.84-0.09+0.08 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.
Key words: stars: individual: TrES-4b / planetary systems / techniques: radial velocities / techniques: spectroscopic / techniques: photometric
Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundacion Galileo Galilei of the INAF at the Spanish Observatorio del Roque de los Muchachos of the IAC in the frame of the program Global Architecture of Planetary Systems (GAPS), and with the Zeiss 1.23-m telescope at the German-Spanish Astronomical Center at Calar Alto, Spain.
Tables 1 and 3 are available in electronic form at http://www.aanda.org
© ESO, 2015
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