The GAPS programme with HARPS-N at TNG. IX. The multi-planet system KELT-6: Detection of the planet KELT-6 c and measurement of the Rossiter-McLaughlin effect for KELT-6 b

Journal
Date Issued
2015
Author(s)
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Esposito, M.
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Bieryla, A.
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Latham, D. W.
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Gandolfi, D.
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Petrovich, C.
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Collins, K. A.
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Piotto, G.
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Di Fabrizio, L.
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Gomez-Jimenez, M.
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Murabito, S.
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Barbieri, M.
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Mancini, L.
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Southworth, J.
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Zanmar Sanchez, R.
DOI
Description
GAPS acknowledges support from INAF through the “Progetti Premiali” funding scheme of the Italian Ministry of Education, University, and Research. M.D. acknowledges support from INAF-OATo through grant 35/2014, and thanks the Astronomical Observatory of the Autonomous Region of the Aosta Valley for its support with computing infrastructure. IRAF is distributed by the National Optical Astronomy Observatories, operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation. We made use of the SIMBAD database and VizieR catalogue access tool, operated at the CDS, Strasbourg, France.
Abstract
Aims: For more than 1.5 years we spectroscopically monitored the star KELT-6 (BD+31 2447), which is known to host the transiting hot-Saturn KELT-6 b, because a previously observed long-term trend in radial velocity time series suggested that there is an outer companion. Methods: We collected a total of 93 new spectra with the HARPS-N and TRES spectrographs. A spectroscopic transit of KELT-6 b was observed with HARPS-N, and simultaneous photometry was obtained with the IAC-80 telescope. Results: We proved the existence of an outer planet with a mininum mass Mpsin i = 3.71 ± 0.21 MJup and a moderately eccentric orbit (e = 0.21-0.036+0.039) of period P ~ 3.5 years. We improved the orbital solution of KELT-6 b and obtained the first measurement of the Rossiter-McLaughlin effect, showing that the planet has a likely circular, prograde, and slightly misaligned orbit with a projected spin-orbit angle of λ = -36 ± 11 degrees. We improved the KELT-6 b transit ephemeris from photometry and provide new measurements of the stellar parameters. KELT-6 appears as an interesting case for studying the formation and evolution of multi-planet systems.

Based on observations made with (i) the HARPS-N spectrograph on the Italian Telescopio Nazionale Galileo (TNG), operated on the island of La Palma by the INAF - Fundacion Galileo Galilei (Spanish Observatory of Roque de los Muchachos of the IAC); (ii) the Tillinghast Reflector Echelle Spectrograph (TRES) on the 1.5-m Tillinghast telescope, located at the Smithsonian Astrophysical Observatory's Fred L. Whipple Observatory on Mt. Hopkins in Arizona; (iii) the IAC-80 telescope at the Teide Observatory (Instituto de Astrofísica de Canarias, IAC).Figure 4 and Tables 2 and 3 are available in electronic form at "http://www.aanda.org/10.1051/0004-6361/201526995/olm"

Volume
581
Start page
L6
Uri
Url
Issn Identifier
0004-6361
Ads BibCode
2015A&A...581L...6D
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open.access
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