HD 207897 b: A dense sub-Neptune transiting a nearby and bright K-type star

Creators: Heidari, N.; Boisse, I.; Orell-Miquel, J.; Hebrard, G.; Acuña, L.; Hara, N. C.; Lillo-Box, J.; Eastman, J. D.; Arnold, L.; Astudillo-Defru, N.; Adibekyan, V.; Bieryla, A.; Bonfils, X.; Bouchy, F.; Barclay, T.; Brasseur, C. E.; Borgniet, S.; Bourrier, V.; Buchhave, L.; Behmard, A.; Beard, C.; Batalha, N. M.; Courcol, B.; Cortés-Zuleta, P.; Collins, K.; Carmona, A.; Crossfield, I. J. M.; Chontos, A.; Delfosse, X.; Dalal, S.; Deleuil, M.; Demangeon, O. D. S.; Díaz, R. F.; Dumusque, X.; Daylan, T.; Dragomir, D.; Delgado Mena, E.; Dressing, C.; Dai, F.; Dalba, P. A.; Ehrenreich, D.; Forveille, T.; Fulton, B.; Fetherolf, T.; Gaisné, G.; Giacalone, S.; Riazi, N.; Hoyer, S.; Hobson, M. J.; Howard, A. W.; Huber, D.; Hill, M. L.; Hirsch, L. A.; Isaacson, H.; Jenkins, J.; Kane, S. R.; Kiefer, F.; Luque, R.; Latham, D. W.; Lubin, J.; Lopez, T.; Mousis, O.; Moutou, C.; Montagnier, G.; Mignon, L.; Mayo, A.; Močnik, T.; Murphy, J. M. A.; Palle, E.; Pepe, F.; Petigura, E. A.; Rey, J.; Ricker, G.; Robertson, P.; Roy, A.; Rubenzahl, R. A.; Rosenthal, L. J.; Santerne, A.; Santos, N. C.; Sousa, S. G.; Stassun, K. G.; Stalport, M.; Scarsdale, N.; Strøm, P. A.; Seager, S.; Segransan, D.; Tenenbaum, P.; Tronsgaard, R.; Udry, S.; Vanderspek, R.; Vakili, F.; Winn, J. N.; Weiss, L. M.

Style

An error occurred while generating the citation.

Abstract

We present the discovery and characterization of a transiting sub-Neptune that orbits the nearby (28 pc) and bright (V = 8.37) K0V star HD 207897 (TOI-1611) with a 16.20-day period. This discovery is based on photometric measurements from the Transiting Exoplanet Survey Satellite mission and radial velocity (RV) observations from the SOPHIE, Automated Planet Finder, and HIRES high-precision spectrographs. We used EXOFASTv2 to model the parameters of the planet and its host star simultaneously, combining photometric and RV data to determine the planetary system parameters. We show that the planet has a radius of 2.50 ± 0.08 R_E and a mass of either 14.4 ± 1.6 M_E or 15.9 ± 1.6 M_E with nearly equal probability. The two solutions correspond to two possibilities for the stellar activity period. The density accordingly is either 5.1 ± 0.7 g cm⁻³ or 5.5_(−0.7)^(+0.8) g cm⁻³, making it one of the relatively rare dense sub-Neptunes. The existence of this dense planet at only 0.12 AU from its host star is unusual in the currently observed sub-Neptune (2 < R_E < 4) population. The most likely scenario is that this planet has migrated to its current position.

Additional Information

© N. Heidari et al. 2022. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Received 29 May 2021; Accepted 8 September 2021; Published online 18 February 2022. We warmly thank the OHP staff for their support on the observations. X.B., I.B. and T.F. received funding from the French Programme National de Physique Stellaire (PNPS) and the Programme National de Planétologie (PNP) of CNRS (INSU). We also acknowledge the financial support of French embassy in Tehran. N.H. acknowledges F. Vakili for his constant academic and administrative support. N.H. warmly thanks Ph. Stee, J. L. Beuzit, E. T. Givenchy for all their help. N.H also thanks Jason D. Eastman and Michael Hippke who have written EXOFASTv2 and TLS package, respectively, for their guides. This publication makes use of The Data & Analysis Center for Exoplanets (DACE), which is a facility based at the University of Geneva (CH) dedicated to extrasolar planets data visualisation, exchange and analysis. DACE is a platform of the Swiss National Centre of Competence in Research (NCCR) PlanetS, federating the Swiss expertise in Exoplanet research. The DACE platform is available at https://dace.unige.ch. J.L-B. acknowledges financial support received from "la Caixa" Foundation (ID 100010434) and from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 847648, with fellowship code LCF/BQ/PI20/11760023. This work has been carried out in the frame of the National Centre for Competence in Research "Planets" supported by the Swiss National Science Foundation (SNSF). This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (project SPICE DUNE, grant agreement No 947634). This work was supported by FCT – Fundação para a Ciência e Tecnologia (FCT) through national funds and by FEDER through COMPETE2020 – Programa OperacionalCompetitividade e Internacionalização by these grants: UID/FIS/04434/2019; UIDB/04434/2020; UIDP/04434/2020; PTDC/FIS-AST/32113/2017 and POCI-01-0145-FEDER-032113; PTDC/FIS-AST/28953/2017 and POCI-01-0145-FEDER-028953. V.A., E.D.M, N.C.S., and S.G.S. also acknowledge the support from FCT through Investigador FCT contracts nr. IF/00650/2015/CP1273/CT0001, IF/00849/2015/CP1273/CT0003, IF/00169/2012/CP0150/CT0002, and IF/00028/2014/CP1215/CT0002, respectively, and POPH/FSE (EC) by FEDER funding through the program "Programa Operacional de Factores de Competitividade – COMPETE". O.D.S.D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by FCT. A.C. et P.C. acknowledge funding from the French National Research Agency (ANR) under contract number ANR-18-CE31-0019 (SPlaSH). N.A.D. acknowledges the support of FONDECYT project 3180063. S.H. acknowledges CNES funding through the grant 837319. X.D. and G.G. acknowledge funding in the framework of the Investissements d'Avenir program (ANR-15-IDEX-02), through the funding of the "Origin of Life" project of the Univ. Grenoble-Alpes. This work was supported by Fundação para a Ciência e a Tecnologia (FCT) and Fundo Europeu de Desenvolvimento Regional (FEDER) via COMPETE2020 through the research grants UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-AST/32113/2017 and POCI-01-0145-FEDER-032113, PTDC/FIS-AST/28953/2017 and POCI-01-0145-FEDER-028953. O.D.S.D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by FCT. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. Funding for the TESS mission is provided by NASA's Science Mission directorate. We acknowledge the use of public TESS Alert data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This paper includes data collected by the TESS mission that are publicly available from the Mikulski Archive for Space Telescopes (MAST). D.D acknowledges support from the TESS Guest Investigator Program grant 80NSSC19K1727 and NASA Exoplanet Research Program grant 18 − 2XRP182 − 0136. T.D acknowledges support from MIT's Kavli Institute as a Kavli postdoctoral fellow. E.A.P. acknowledges the support of the Alfred P. Sloan Foundation. L.M.W. is supported by the Beatrice Watson Parrent Fellowship and NASA ADAP Grant 80NSSC19K0597. A.C. is supported by the NSF Graduate Research Fellowship, grant No. DGE 1842402. D.H. acknowledges support from the Alfred P. Sloan Foundation, the National Aeronautics and Space Administration (80NSSC19K0379), and the National Science Foundation (AST-1717000). I.J.M.C. acknowledges support from the NSF through grant AST-1824644. P.D. acknowledges support from a National Science Foundation Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1903811. A.B. is supported by the NSF Graduate Research Fellowship, grant No. DGE 1745301. R.A.R. is supported by the NSF Graduate Research Fellowship, grant No. DGE 1745301. C.D.D. acknowledges the support of the Hellman Family Faculty Fund, the Alfred P. Sloan Foundation, the David and Lucile Packard Foundation, and the National Aeronautics and Space Administration via the TESS Guest Investigator Program (80NSSC18K1583). J.M.A.M. is supported by the NSF Graduate Research Fellowship, grant No. DGE-1842400. J.M.A.M. and P.C. acknowledge the LSSTC Data Science Fellowship Program, which is funded by LSSTC, NSF Cybertraining Grant No. 1829740, the Brinson Foundation, and the Moore Foundation; their participation in the program has benefited this work. This paper is partially based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias.

Attached Files

Published - aa41429-21.pdf

Accepted Version - 2110.08597.pdf

Files

2110.08597.pdf

Files (3.8 MB)

Name	Size	Download all
2110.08597.pdf md5:2e4a6cfe4162d605134186a49b4bc003	1.8 MB	Preview Download
aa41429-21.pdf md5:0e7b76d6955a61267cc893eb9f23c31a	2.0 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes