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The K2-ESPRINT Project II: Spectroscopic follow-up of three exoplanet systems from Campaign 1 of K2

Van Eylen, Vincent and Nowak, Grzegorz and Albrecht, Simon and Palle, Enric and Ribas, Ignasi and Bruntt, Hans and Perger, Manuel and Gandolfi, Davide and Hirano, Teriyuki and Sanchis-Ojeda, Roberto and Kiilerich, Amanda and Prieto-Arranz, Jorge and Badenas, Mariona and Dai, Fei and Deeg, Hans J. and Guenther, Eike W. and Montañés-Rodríguez, Pilar and Narita, Norio and Rogers, Leslie A. and Béjar, Víctor J. S. and Shrotriya, Tushar S. and Winn, Joshua N. and Sebastian, Daniel (2016) The K2-ESPRINT Project II: Spectroscopic follow-up of three exoplanet systems from Campaign 1 of K2. Astrophysical Journal, 820 (1). Art. No. 56. ISSN 0004-637X.

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We report on Doppler observations of three transiting planet candidates that were detected during Campaign 1 of the K2 mission. The Doppler observations were conducted with FIES, HARPS-N, and HARPS. We measure the mass of EPIC 201546283b, and provide constraints and upper limits for EPIC 201295312b and EPIC 201577035b. EPIC 201546283b is a warm Neptune orbiting its host star in 6.77 days and has a radius of 4.45_(-0.33)^(+0.33)R_⊕ and a mass of 29.1_(-7.4)^(+7.5)M_⊕, which leads to a mean density of 1.80_(-0.55)^(+0.70) cm^(-3). EPIC 201295312b is smaller than Neptune with an orbital period of 5.66 days, a radius of 2.75_(-0.22^)(0.24)R_⊕, and we constrain the mass to be below 12 M_⊕ at 95% confidence. We also find a long-term trend indicative of another body in the system. EPIC 201577035b, which was previously confirmed as the planet K2-10b, is smaller than Neptune, orbiting its host star in 19.3 days, with a radius of 3.84_(-0.34)^(+0.35)R_⊕. We determine its mass to be 27_(-16)^(+17)M_⊕, with a 95% confidence upper limit at 57M_⊕, and a mean density of 2.6_(-1.6)^(+2.1)g cm^(-3). These measurements join the relatively small collection of planets smaller than Neptune with measurements or constraints of the mean density. Our code for performing K2 photometry and detecting planetary transits is now publicly available.

Item Type:Article
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URLURL TypeDescription Paper
Van Eylen, Vincent0000-0001-5542-8870
Sanchis-Ojeda, Roberto0000-0002-6193-972X
Dai, Fei0000-0002-8958-0683
Rogers, Leslie A.0000-0003-0638-3455
Winn, Joshua N.0000-0002-4265-047X
Additional Information:© 2016 The American Astronomical Society. Received 2015 September 9; accepted 2016 February 1; published 2016 March 17. We appreciate the referee's quick and thoughtful comments and suggestions, which significantly improved the manuscript. We are grateful for the Python implementation of a BLS algorithm by Ruth Angus and Dan Foreman-Mackey. We are thankful to the GAPS consortium, which kindly agreed to exchange time with us, and the KEST team, which shared observations. Based on observations made with the NOT and TNG telescopes operated on the island of La Palma in the Observatorio del Roque de Los Muchachos of the Instituto de Astrofísica de Canarias, as well as observations with the HARPS spectrograph at ESO's La Silla observatory (095.C-0718(A)). Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (grant agreement no. DNRF106). The research is supported by the ASTERISK project (ASTERoseismic Investigations with SONG and Kepler) funded by the European Research Council (grant agreement no. 267864). We acknowledge ASK for covering travels in relation to this publication. This research has made use of the Exoplanet Orbit Database and the Exoplanet Data Explorer at This work was performed (in part) under contract with the Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. I.R. and M.P. acknowledge support from the Spanish Ministry of Economy and Competitiveness (MINECO) and the Fondo Europeo de Desarrollo Regional (FEDER) through grants ESP2013-48391-C4-1-R and ESP2014-57495-C2-2-R. N.N. acknowledges supports by the NAOJ Fellowship, Inoue Science Research Award, and Grant-in-Aid for Scientific Research (A) (JSPS KAKENHI Grant Number 25247026). T.H. is supported by Japan Society for Promotion of Science (JSPS) Fellowship for Research (No.25-3183). L.A.R. gratefully acknowledges support provided by NASA through Hubble Fellowship grant #HF-51313 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. H.D. acknowledges support by grant AYA2012-39346-C02-02 of the Spanish Secretary of State for R&D&i (MICINN).
Funding AgencyGrant Number
Danish National Research FoundationDNRF106
European Research Council (ERC)267864
Ministerio de Economía y Competitividad (MINECO)UNSPECIFIED
Fondo Europeo de Desarrollo Regional (FEDER)ESP2013-48391-C4-1-R
Fondo Europeo de Desarrollo Regional (FEDER)ESP2014-57495-C2-2-R
National Astronomical Observatory of Japan (NAOJ)UNSPECIFIED
Inoue Prize for ScienceUNSPECIFIED
Japan Society for Promotion of Science (JSPS)JPS KAKENHI 25247026
Japan Society for Promotion of Science (JSPS)25-3183
NASA Hubble FellowshipHF-51313
Space Telescope Science InstituteUNSPECIFIED
NASANAS 5-26555
Ministerio de Economía y Competitividad (MICINN)AYA2012-39346-C02-02
Issue or Number:1
Record Number:CaltechAUTHORS:20160426-152339520
Persistent URL:
Official Citation:Vincent Van Eylen et al 2016 ApJ 820 56
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:66491
Deposited By: Ruth Sustaita
Deposited On:27 Apr 2016 02:55
Last Modified:25 Feb 2020 18:09

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