Issue |
A&A
Volume 658, February 2022
|
|
---|---|---|
Article Number | A176 | |
Number of page(s) | 17 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202141429 | |
Published online | 18 February 2022 |
HD 207897 b: A dense sub-Neptune transiting a nearby and bright K-type star
1
Department of Physics, Shahid Beheshti University,
Tehran,
Iran
2
Laboratoire J.-L. Lagrange, Observatoire de la Côte d’Azur (OCA), Universite de Nice-Sophia Antipolis (UNS), CNRS, Campus Valrose,
06108
Nice Cedex 2,
France
3
Aix Marseille Univ, CNRS, CNES, LAM, Marseille,
France
4
Instituto de Astrofísica de Canarias,
38205
La Laguna,
Tenerife,
Spain
5
Departamento de Astrofísica, Universidad de La Laguna,
38206
La Laguna,
Tenerife,
Spain
6
Observatoire de Haute-Provence, CNRS, Université d’Aix- Marseille,
04870
Saint-Michel-l’Observatoire,
France
7
Institut d’astrophysique de Paris, UMR 7095 CNRS université Pierre et Marie Curie, 98 bis, boulevard Arago,
75014
Paris,
France
8
Observatoire de Genève, Université de Genève, Chemin Pegasi,
51,
1290
Sauverny,
Switzerland
9
Centro de Astrobiología (CAB, CSIC-INTA), Depto. de Astrofísica, ESAC campus,
28692,
Villanueva de la Cañada (Madrid),
Spain
10
Center for Astrophysics | Harvard & Smithsonian,
60 Garden St,
Cambridge,
MA
02138,
USA
11
Canada France Hawaii Telescope Corporation (CFHT),
65-1238 Mamalahoa Hwy,
Kamuela HI
96743
USA
12
Departamento de Matemática y Física Aplicadas, Universidad Católica de la Santísima Concepción,
Alonso de Rivera
2850,
Concepción,
Chile
13
Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas,
4150-762
Porto,
Portugal
14
Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre,
4169-007
Porto,
Portugal
15
Univ. Grenoble Alpes, CNRS, IPAG,
38000
Grenoble,
France
16
NASA Goddard Space Flight Center,
8800 Greenbelt Rd,
Greenbelt,
MD 20771,
USA
17
University of Maryland,
Baltimore County, 1000 Hilltop Cir,
Baltimore,
MD 21250,
USA
18
Space Telescope Science Institute,
3700 San Martin Dr,
Baltimore,
MD 21218,
USA
19
Division of Geological and Planetary Science, California Institute of Technology,
Pasadena,
CA 91125,
USA
20
Department of Physics & Astronomy, University of California Irvine,
Irvine,
CA 92697,
USA
21
Department of Astronomy and Astrophysics, University of California,
Santa Cruz,
CA 95060,
USA
22
Department of Physics & Astronomy, University of Kansas,
1082 Malott, 1251 Wescoe Hall Dr.,
Lawrence,
KS 66045,
USA
23
Institute for Astronomy, University of Hawai‘i,
2680 Woodlawn Drive,
Honolulu,
HI 96822,
USA
24
International Center for Advanced Studies (ICAS) and ICIFI (CONICET),
ECyT-UNSAM, Campus Miguelete, 25 de Mayo y Francia,
(1650) Buenos Aires,
Argentina
25
Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology,
Cambridge,
MA 02139,
USA
26
Department of Physics and Astronomy, University of New Mexico,
1919 Lomas Blvd NE,
Albuquerque,
NM 87131,
USA
27
Department of Astronomy, University of California Berkeley,
Berkeley,
CA,
94720,
USA
28
Division of Geological and Planetary Sciences 1200 E California Blvd,
Pasadena,
CA,
91125,
USA
29
Department of Earth and Planetary Sciences, University of California,
Riverside,
CA 92521,
USA
30
NASA Exoplanet Science Institute/Caltech-IPAC,
MC 314-6, 1200 E. California Blvd.,
Pasadena,
CA 91125,
USA
31
Millennium Institute for Astrophysics,
Chile
32
Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile,
Chile
33
Department of Astronomy, California Institute of Technology,
Pasadena,
CA 91125,
USA
34
Kavli Institute for Particle Astrophysics and Cosmology, Stanford University,
Stanford,
CA 94305,
USA
35
Centre for Astrophysics, University of Southern Queensland,
Toowoomba,
QLD,
Australia
36
Department of Physics & Astronomy, University of California Los Angeles,
Los Angeles,
CA 90095,
USA
37
Las Campanas Observatory, Carnegie Institution of Washington, Colina el Pino,
Casilla 601 La Serena,
Chile
38
Department of Physics and Astronomy, Johns Hopkins University,
3400 N Charles St,
Baltimore,
MD 21218,
USA
39
Gemini Observatory/NSF’s NOIRLab,
670 N. A’ohoku Place,
Hilo,
HI 96720,
USA
40
LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris,
5 place Jules Janssen,
92195,
Meudon,
France
41
Univ. de Toulouse, CNRS, IRAP,
14 avenue Belin,
31400
Toulouse,
France
42
Vanderbilt University, Department of Physics & Astronomy,
6301 Stevenson Center Ln.,
Nashville,
TN 37235,
USA
43
SETI Institute/NASA Ames Research Center,
USA
44
DTU Space, National Space Institute, Technical University of Denmark,
Elektrovej 328,
2800
Kgs. Lyngby,
Denmark
45
Department of Astrophysical Sciences, Princeton University,
4Ivy Lane,
Princeton,
NJ 08544,
USA
46
NASA Ames Research Center,
Moffett Field,
CA,
94035,
USA
47
Department of Physics, University of Warwick,
Coventry,
CV4 7AL,
UK
48
Centre for Exoplanets and Habitability, University of Warwick,
Gibbet Hill Road,
Coventry,
CV4 7AL,
UK
49
Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology,
Cambridge,
MA 02139,
USA
50
Department of Aeronautics and Astronautics,
MIT, 77 Massachusetts Avenue,
Cambridge,
MA 02139,
USA
Received:
29
May
2021
Accepted:
8
September
2021
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 RE and a mass of either 14.4 ± 1.6 ME or 15.9 ± 1.6 ME 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 < RE < 4) population. The most likely scenario is that this planet has migrated to its current position.
© 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.
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