Two warm Neptunes transiting HIP 9618 revealed by TESS and Cheops
Journal article, 2023
HIP 9618 (HD 12572, TOI-1471, TIC 306263608) is a bright (G = 9.0 mag) solar analogue. TESS photometry revealed the star to have two candidate planets with radii of 3.9 ± 0.044 R (HIP 9618 b) and 3.343 ± 0.039 R (HIP 9618 c). While the 20.77291 d period of HIP 9618 b was measured unambiguously, HIP 9618 c showed only two transits separated by a 680-d gap in the time series, leaving many possibilities for the period. To solve this issue, CHEOPS performed targeted photometry of period aliases to attempt to recover the true period of planet c, and successfully determined the true period to be 52.56349 d. High-resolution spectroscopy with HARPS-N, SOPHIE, and CAFE revealed a mass of 10.0 ± 3.1M for HIP 9618 b, which, according to our interior structure models, corresponds to a 6.8 ± 1.4 per cent gas fraction. HIP 9618 c appears to have a lower mass than HIP 9618 b, with a 3-sigma upper limit of <18M. Follow-up and archival RV measurements also reveal a clear long-term trend which, when combined with imaging and astrometric information, reveal a low-mass companion (0.08+−000512M☉) orbiting at 26.0+−111900 au. This detection makes HIP 9618 one of only five bright (K < 8 mag) transiting multiplanet systems known to host a planet with P > 50 d, opening the door for the atmospheric characterization of warm (Teq < 750 K) sub-Neptunes.
surveys
occultations
planets and satellites: detection
eclipses
binaries: spectroscopic
Author
H. P. Osborn
Massachusetts Institute of Technology (MIT)
University of Bern
G. Nowak
Nicolaus Copernicus University
University of La Laguna
Instituto de Astrofísica de Canarias
G. Hebrard
Institut d 'Astrophysique de Paris
T. Masseron
University of La Laguna
Instituto de Astrofísica de Canarias
J. Lillo-Box
European Space Agency (ESA)
E. Palle
Instituto de Astrofísica de Canarias
University of La Laguna
A. Bekkelien
University of Geneva
H.-G. Florén
Stockholm University
P. Guterman
Laboratoire d'Astrophysique de Marseille
A.E. Simon
University of Bern
V. Adibekyan
University of Porto
Allyson Bieryla
Harvard-Smithsonian Center for Astrophysics
L. Borsato
Istituto nazionale di astrofisica (INAF)
A. Brandeker
Stockholm University
D. R. Ciardi
National Aeronautics and Space Administration (NASA)
A. Collier Cameron
University of St Andrews
K. A. Collins
Harvard-Smithsonian Center for Astrophysics
J. A. Egger
University of Bern
D. Gandolfi
University of Turin
M.J. Hooton
University of Bern
University of Cambridge
D. W. Latham
Harvard-Smithsonian Center for Astrophysics
M. Lendl
University of Geneva
E. C. Matthews
University of Geneva
Max Planck Society
A. Tuson
University of Cambridge
S. Ulmer-Moll
University of Geneva
A. Vanderburg
Massachusetts Institute of Technology (MIT)
T.G. Wilson
University of St Andrews
C. Ziegler
Stephen F. Austin State University
Y. Alibert
University of Bern
R. Alonso
Instituto de Astrofísica de Canarias
University of La Laguna
G. Anglada
Spanish National Research Council (CSIC)
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
L. Arnold
Centre national de la recherche scientifique (CNRS)
J. Asquier
European Space Agency (ESA)
D. Barrado Y Navascues
Centro de Astrobiologia (CAB)
W. Baumjohann
Institut fur Weltraumforschung
T. Beck
University of Bern
A. A. Belinski
Moscow State University
W. Benz
University of Bern
F. Biondi
Istituto nazionale di astrofisica (INAF)
Max Planck Society
I. Boisse
Laboratoire d'Astrophysique de Marseille
X. Bonfils
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
C. Broeg
University of Bern
L. A. Buchhave
Technical University of Denmark (DTU)
T. Bárczy
Admatis
S.C.C. Barros
University of Porto
J. Cabrera
German Aerospace Center (DLR)
C. Cardona Guillen
Instituto de Astrofísica de Canarias
University of La Laguna
Ilaria Carleo
University of La Laguna
Instituto de Astrofísica de Canarias
A. Castro-González
European Space Agency (ESA)
S. Charnoz
Institut de Physique du Globe de Paris
Jessie L. Christiansen
National Aeronautics and Space Administration (NASA)
Pía Cortés-Zuleta
Laboratoire d'Astrophysique de Marseille
Szilard Csizmadia
German Aerospace Center (DLR)
S. Dalal
Institut d 'Astrophysique de Paris
M. B. Davies
Lund University
M. Deleuil
Laboratoire d'Astrophysique de Marseille
X. Delfosse
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
L. Delrez
University of Liège
B.O. Demory
University of Bern
A. B. Dunlavey
National Aeronautics and Space Administration (NASA)
D. Ehrenreich
University of Geneva
Anders Erikson
German Aerospace Center (DLR)
R. B. Fernandes
University of Arizona
A. Fortier
University of Bern
T. Forveille
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
L. Fossati
Institut fur Weltraumforschung
Malcolm Fridlund
Leiden University
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Michaël Gillon
University of Liège
Robert Goeke
Massachusetts Institute of Technology (MIT)
M. V. Goliguzova
Moscow State University
E. Gonzales
University of California
Maximilian N. Günther
European Space Agency (ESA)
M. Gudel
University of Vienna
N. Heidari
Laboratoire d'Astrophysique de Marseille
C. E. Henze
National Aeronautics and Space Administration (NASA)
S. B. Howell
National Aeronautics and Space Administration (NASA)
S. Hoyer
Laboratoire d'Astrophysique de Marseille
J. I. Frey
University of Bern
K. Isaak
European Space Agency (ESA)
Jon M. Jenkins
National Aeronautics and Space Administration (NASA)
F. Kiefer
Paris Observatory
Institut d 'Astrophysique de Paris
L.L. Kiss
Hungarian Academy of Sciences
Eötvös Loránd University (ELTE)
Judith Korth
Lund University
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
P. Maxted
Keele University
J. Laskar
Paris Observatory
A. L. des Etangs
Institut d 'Astrophysique de Paris
C. Lovis
University of Geneva
M. B. Lund
National Aeronautics and Space Administration (NASA)
R. Luque
University of Chicago
D. Magrin
Istituto nazionale di astrofisica (INAF)
J. M. Almenara
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
E. Martioli
Institut d 'Astrophysique de Paris
Laboratorio Nacional de Astrofisica, Itajuba
M. Mecina
University of Vienna
J. V. Medina
Space Telescope Science Institute (STScI)
D. Moldovan
Google Inc.
M. Morales-Calderon
European Space Agency (ESA)
Giuseppe Morello
Instituto de Astrofísica de Canarias
University of La Laguna
C. Moutou
Institut de Recherche en Astrophysique et Planétologie (IRAP)
F. Murgas
University of La Laguna
Instituto de Astrofísica de Canarias
Eric L.N. Jensen
Swarthmore College
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 523 2 3069-3089Exoplanet diversity with satellite studies
Swedish National Space Board (174/18), 2019-02-04 -- 2023-08-01.
Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.1093/mnras/stad1319