TOI-332 b: a super dense Neptune found deep within the Neptunian desert
Journal article, 2023
To date, thousands of planets have been discovered, but there are regions of the orbital parameter space that are still bare. An example is the short period and intermediate mass/radius space known as the 'Neptunian desert', where planets should be easy to find but discoveries remain few. This suggests unusual formation and evolution processes are responsible for the planets residing here. We present the discovery of TOI-332 b, a planet with an ultra-short period of 0.78 d that sits firmly within the desert. It orbits a K0 dwarf with an effective temperature of 5251 ± 71 K. TOI-332 b has a radius of R, smaller than that of Neptune, but an unusually large mass of 57.2 ± 1.6 M. It has one of the highest densities of any Neptune-sized planet discovered thus far at g cm-3. A 4-layer internal structure model indicates it likely has a negligible hydrogen-helium envelope, something only found for a small handful of planets this massive, and so TOI-332 b presents an interesting challenge to planetary formation theories. We find that photoevaporation cannot account for the mass-loss required to strip this planet of the Jupiter-like envelope it would have been expected to accrete. We need to look towards other scenarios, such as high-eccentricity migration, giant impacts, or gap opening in the protoplanetary disc, to try and explain this unusual discovery.
planets and satellites: detection
planets and satellites: individual: (TOI-332, TIC 139285832)
Author
A. Osborn
The University of Warwick
D. J. Armstrong
The University of Warwick
Jorge Fernández Fernández
The University of Warwick
Henrik Knierim
University of Zürich
V. Adibekyan
University of Porto
Karen A. Collins
Harvard-Smithsonian Center for Astrophysics
E. Delgado Mena
University of Porto
Malcolm Fridlund
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
J. Gomes da Silva
University of Porto
Coel Hellier
Keele University
David G. Jackson
Queen's University Belfast
George W King
University of Michigan
Max Planck Society
J. Lillo-Box
Centro de Astrobiologia (CAB)
Rachel A. Matson
US Naval Observatory
Elisabeth Matthews
Max Planck Society
N. C. Santos
University of Porto
S.G. Sousa
University of Porto
Keivan G. Stassun
Vanderbilt University
Thiam Guan Tan
Perth Exoplanet Survey Telescope
George R. Ricker
Massachusetts Institute of Technology (MIT)
Roland K. Vanderspek
Massachusetts Institute of Technology (MIT)
D. W. Latham
Harvard-Smithsonian Center for Astrophysics
S. Seager
Massachusetts Institute of Technology (MIT)
J. N. Winn
Princeton University
Jon M. Jenkins
National Aeronautics and Space Administration (NASA)
D. Bayliss
The University of Warwick
L. Bouma
California Institute of Technology (Caltech)
D. R. Ciardi
National Aeronautics and Space Administration (NASA)
Kevin I. Collins
George Mason University
K. D. Colón
National Aeronautics and Space Administration (NASA)
I. J.M. Crossfield
Massachusetts Institute of Technology (MIT)
O. Demangeon
University of Porto
R. F. Diaz
Consejo Nacional de Investigaciones Cientificas y Tecnicas
C. Dorn
Swiss Federal Institute of Technology in Zürich (ETH)
X. Dumusque
University of Geneva
Marcelo Aron Fetzner Keniger
The University of Warwick
P. Figueira
University of Porto
University of Geneva
Tianjun Gan
Tsinghua University
Robert Goeke
Massachusetts Institute of Technology (MIT)
A. Hadjigeorghiou
The University of Warwick
F. Hawthorn
The University of Warwick
R. Helled
University of Zürich
S.B. Howell
National Aeronautics and Space Administration (NASA)
L. D. Nielsen
European Southern Observatory (ESO)
H. P. Osborn
University of Bern
Samuel N. Quinn
Harvard-Smithsonian Center for Astrophysics
Ramotholo Sefako
South African Astronomical Observatory
Avi Shporer
Massachusetts Institute of Technology (MIT)
P. A. Strøm
The University of Warwick
J. D. Twicken
National Aeronautics and Space Administration (NASA)
SETI Institute
A. Vanderburg
Massachusetts Institute of Technology (MIT)
P. J. Wheatley
The University of Warwick
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 526 1 548-566Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
Other Physics Topics
DOI
10.1093/mnras/stad2575