A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system
Journal article, 2022
It is commonly accepted that exoplanets with orbital periods shorter than one day, also known as ultra-short-period (USP) planets, formed further out within their natal protoplanetary disks before migrating to their current-day orbits via dynamical interactions. One of the most accepted theories suggests a violent scenario involving high-eccentricity migration followed by tidal circularization. Here we present the discovery of a four-planet system orbiting the bright (V = 10.5) K6 dwarf star TOI-500. The innermost planet is a transiting, Earth-sized USP planet with an orbital period of ~13 hours, a mass of 1.42 ± 0.18 M⊕, a radius of 1.166−0.058+0.061R⊕ and a mean density of 4.89−0.88+1.03gcm−3. Via Doppler spectroscopy, we discovered that the system hosts 3 outer planets on nearly circular orbits with periods of 6.6, 26.2 and 61.3 days and minimum masses of 5.03 ± 0.41 M⊕, 33.12 ± 0.88 M⊕ and 15.05−1.11+1.12M⊕, respectively. The presence of both a USP planet and a low-mass object on a 6.6-day orbit indicates that the architecture of this system can be explained via a scenario in which the planets started on low-eccentricity orbits then moved inwards through a quasi-static secular migration. Our numerical simulations show that this migration channel can bring TOI-500 b to its current location in 2 Gyr, starting from an initial orbit of 0.02 au. TOI-500 is the first four-planet system known to host a USP Earth analogue whose current architecture can be explained via a non-violent migration scenario.
Author
L. M. Serrano
University of Turin
D. Gandolfi
University of Turin
A. J. Mustill
Lund University
O. Barragán
University of Oxford
Judith Korth
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Fei Dai
California Institute of Technology (Caltech)
S. Redfield
Wesleyan University
Malcolm Fridlund
Leiden University
K. W.F. Lam
Technische Universität Berlin
Matías R. Díaz
Las Campanas Observatory
University of Chile (UCH)
S. Grziwa
University of Cologne
Karen A. Collins
Harvard-Smithsonian Center for Astrophysics
J.H. Livingston
University of Tokyo
William D. Cochran
The University of Texas at Austin
Coel Hellier
Keele University
Salvatore E. Bellomo
University of Turin
T. Trifonov
Sofia University
Max Planck Society
F. Rodler
European Southern Observatory Santiago
Javier Alarcon
European Southern Observatory Santiago
Jon M. Jenkins
NASA Ames Research Center
D. W. Latham
Harvard-Smithsonian Center for Astrophysics
George R. Ricker
Massachusetts Institute of Technology (MIT)
S. Seager
Massachusetts Institute of Technology (MIT)
Roland Vanderspeck
Massachusetts Institute of Technology (MIT)
J. N. Winn
Princeton University
Simon Albrecht
Aarhus University
Kevin I. Collins
George Mason University
Szilárd Csizmadia
German Aerospace Center (DLR)
Tansu Daylan
Massachusetts Institute of Technology (MIT)
H. Deeg
University of La Laguna
Instituto de Astrofísica de Canarias
M. Esposito
Thüringer Landessternwarte Tautenburg
Michael Fausnaugh
Massachusetts Institute of Technology (MIT)
Iskra Georgieva
Leiden University
E. Goffo
University of Turin
Thüringer Landessternwarte Tautenburg
E. W. Guenther
Thüringer Landessternwarte Tautenburg
A. Hatzes
Thüringer Landessternwarte Tautenburg
S.B. Howell
NASA Ames Research Center
Eric L.N. Jensen
Swarthmore College
R. Luque
Instituto de Astrofísica de Canarias
University of La Laguna
A. Mann
The University of North Carolina System
F. Murgas
University of La Laguna
Instituto de Astrofísica de Canarias
H. L.M. Osborne
University College London (UCL)
Enric Palle
Instituto de Astrofísica de Canarias
University of La Laguna
Carina Persson
Leiden University
Pamela Rowden
Royal Astronomical Society
Alexander Rudat
Massachusetts Institute of Technology (MIT)
Alexis M. S. Smith
German Aerospace Center (DLR)
J. D. Twicken
SETI Institute
NASA Ames Research Center
Vincent Van Eylen
University College London (UCL)
C. Ziegler
Stephen F. Austin State University
Nature Astronomy
23973366 (eISSN)
Vol. 6 6 736-750Subject Categories
Astronomy, Astrophysics and Cosmology
Other Physics Topics
Embedded Systems
DOI
10.1038/s41550-022-01641-y