TOI−757 b: an eccentric transiting mini−Neptune on a 17.5−d orbit
Journal article, 2024
We report the spectroscopic confirmation and fundamental properties of TOI−757 b, a mini−Neptune on a 17.5−d orbit transiting a bright star (V = 9.7 mag) discovered by the TESS mission. We acquired high−precision radial velocity measurements with the HARPS, ESPRESSO, and PFS spectrographs to confirm the planet detection and determine its mass. We also acquired space−borne transit photometry with the CHEOPS space telescope to place stronger constraints on the planet radius, supported with ground−based LCOGT photometry. WASP and KELT photometry were used to help constrain the stellar rotation period. We also determined the fundamental parameters of the host star. We find that TOI−757 b has a radius of Rp = 2.5 ± 0.1R. and a mass of Mp = 10.5+−2212M, implying a bulk density of ρp = 3.6 ± 0.8 g cm−3. Our internal composition modelling was unable to constrain the composition of TOI−757 b, highlighting the importance of atmospheric observations for the system. We also find the planet to be highly eccentric with e = 0.39+−000708, making it one of the very few highly eccentric planets among precisely characterized mini−Neptunes. Based on comparisons to other similar eccentric systems, we find a likely scenario for TOI−757 b’s formation to be high eccentricity migration due to a distant outer companion. We additionally propose the possibility of a more intrinsic explanation for the high eccentricity due to star−star interactions during the earlier epoch of the Galactic disc formation, given the low metallicity and older age of TOI−757.
planets and satellites: composition
planets and satellites: interiors
techniques: photometric
techniques: radial velocities
stars: individual: TOI-757 (TIC 130924120)
Author
A. Alqasim
University College London (UCL)
N. Grieves
University of Geneva
N. M. Rosário
University of Porto
D. Gandolfi
University of Turin
J.H. Livingston
University of Tokyo
S.G. Sousa
University of Porto
Karen A. Collins
Harvard-Smithsonian Center for Astrophysics
J. K. Teske
Carnegie Institution of Washington
Malcolm Fridlund
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
J. A. Egger
University of Bern
J. Cabrera
German Aerospace Center (DLR)
Coel Hellier
Keele University
A. F. Lanza
Istituto nazionale di astrofisica (INAF)
Vincent Van Eylen
University College London (UCL)
F. Bouchy
University of Geneva
R.J. Oelkers
Texas A&M University
G. Srdoc
Kotizarovci Observatory
T.G. Wilson
European Space Agency (ESA)
E. Goffo
University of Turin
L. Delrez
Technische Universität Graz
Ramotholo Sefako
University of Turin
S.C.C. Barros
The University of Warwick
Kevin I. Collins
Stockholm University
A. Heitzmann
Tsinghua University
A. Bonfanti
University of Geneva
T. Bárczy
University of Bern
D. Barrado Navascues
University of Bern
N. Billot
South African Astronomical Observatory
L. Borsato
University of Porto
C. Broeg
George Mason University
R. Alonso
Aarhus University
J. Asquier
European Space Agency (ESA)
W. Baumjohann
University of Geneva
W. Benz
University of Bern
E. Bryant
University College London (UCL)
R.P. Butler
Carnegie Institution of Washington
A. Collier Cameron
University of Texas
A. Correia
University of St Andrews
J.D. Crane
Carnegie Observatories
P. E. Cubillos
University of Geneva
M. B. Davies
Istituto nazionale di astrofisica (INAF)
A. Deline
University of Geneva
B.O. Demory
University of Bern
M. Deleuil
European Space Agency (ESA)
William D. Cochran
Istituto nazionale di astrofisica (INAF)
Szilard Csizmadia
German Aerospace Center (DLR)
A. Derekas
Laboratoire d'Astrophysique de Marseille
Billy Edwards
Eötvös Loránd University (ELTE)
Tansu Daylan
Lund University
Anders Erikson
German Aerospace Center (DLR)
K. Gazeas
University of New Mexico
M. Gudel
University of Athens
J. Hasiba
University of Geneva
A. Hatzes
Thüringer Landessternwarte Tautenburg
Ch. Helling
Thüringer Landessternwarte Tautenburg
T. Hirano
University of Vienna
Jon M. Jenkins
National Astronomical Observatory of Japan
S. Kanodia
Carnegie Institution of Washington
L. L. Kiss
National Aeronautics and Space Administration (NASA)
J. Laskar
Lund University
A. L. des Etangs
Paris Observatory
M. Lendl
University of Geneva
M. B. Lund
Institut d 'Astrophysique de Paris
R. Luque
California Institute of Technology (Caltech)
A. Mann
University of Chicago
D. Magrin
European Space Agency (ESA)
P. Maxted
Keele University
C. Mordasini
University of Bern
A. Fortier
University of Bern
G. Olofsson
The University of Warwick
D. Ehrenreich
University of Geneva
I. Pagano
Istituto nazionale di astrofisica (INAF)
Valerio Nascimbeni
University of Athens
H. P. Osborn
European Space Agency (ESA)
N. Rando
European Space Agency (ESA)
R. Ottensamer
German Aerospace Center (DLR)
K. Isaak
European Space Agency (ESA)
Judith Korth
Eötvös Loránd University (ELTE)
Michaël Gillon
University of Bern
G. Peter
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
Giampaolo P. Piotto
Nicolaus Copernicus University
S. Hoyer
University of Washington
S.B. Howell
National Astronomical Observatory of Japan
M. Rieder
University of Bern
E. Palle
Aarhus University
Zahra Essack
University of Geneva
K. W.F. Lam
European Space Agency (ESA)
Roberto Ragazzoni
University of Geneva
H. Rauer
University of Porto
S. Redfield
Istituto nazionale di astrofisica (INAF)
I. Ribas
Nicolaus Copernicus University
D. Segransan
University of Geneva
George R. Ricker
Nicolaus Copernicus University
N. C. Santos
University of Bern
Gaetano Scandariato
German Aerospace Center (DLR)
M. Stalport
University of Bern
Avi Shporer
Carnegie Observatories
A.E. Simon
National Astronomical Observatory of Japan
Alexis M. S. Smith
University of Geneva
G.M. Szabó
Nicolaus Copernicus University
J. D. Twicken
University of Liège
S. Udry
University of Geneva
Roland K. Vanderspek
Aarhus University
V. Van Grootel
Nicolaus Copernicus University
J. Venturini
European Space Agency (ESA)
V. Viotto
European Space Agency (ESA)
N. A. Walton
SETI Institute
J. N. Winn
University of Cambridge
S.W. Yee
Harvard-Smithsonian Center for Astrophysics
Monthly Notices of the Royal Astronomical Society
00358711 (ISSN) 13652966 (eISSN)
Vol. 533 1 1-26Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.1093/mnras/stae1767