Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system

Serrano, Luisa Maria ; Gandolfi, Davide ; Mustill, Alexander J. LU orcid ; Barragán, Oscar ; Korth, Judith LU ; Dai, Fei ; Redfield, Seth ; Fridlund, Malcolm ; Lam, Kristine W. F. and Díaz, Matías R. , et al. (2022) In Nature Astronomy 6(6). p.736-750
Abstract
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 $$1.16{6}_{-0.058}^{+0.061} \,R_{\oplus}$$and a mean density of... (More)
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 $$1.16{6}_{-0.058}^{+0.061} \,R_{\oplus}$$and a mean density of $$4.8{9}_{-0.88}^{+1.03}\,{{{\rm{g}}}}\,{{{{\rm{cm}}}}}^{-3}$$. 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 $$15.0{5}_{-1.11}^{+1.12}\,M_{\oplus}$$, 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. (Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; ; and , et al. (More)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; and (Less)
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Nature Astronomy
volume
6
issue
6
pages
15 pages
publisher
Nature Publishing Group
external identifiers
  • scopus:85129057819
ISSN
2397-3366
DOI
10.1038/s41550-022-01641-y
project
Consolidating CHEOPS and preparing for PLATO: Exoplanet studies in the 2020s
language
English
LU publication?
yes
id
8d3d320f-db3b-4c65-884d-68d2011b6c7a
alternative location
https://arxiv.org/abs/2204.13573
date added to LUP
2022-05-03 12:47:32
date last changed
2024-04-18 09:56:56
@article{8d3d320f-db3b-4c65-884d-68d2011b6c7a,
  abstract     = {{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 $$1.16{6}_{-0.058}^{+0.061} \,R_{\oplus}$$and a mean density of $$4.8{9}_{-0.88}^{+1.03}\,{{{\rm{g}}}}\,{{{{\rm{cm}}}}}^{-3}$$. 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 $$15.0{5}_{-1.11}^{+1.12}\,M_{\oplus}$$, 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       = {{Serrano, Luisa Maria and Gandolfi, Davide and Mustill, Alexander J. and Barragán, Oscar and Korth, Judith and Dai, Fei and Redfield, Seth and Fridlund, Malcolm and Lam, Kristine W. F. and Díaz, Matías R. and Grziwa, Sascha and Collins, Karen A. and Livingston, John H. and Cochran, William D. and Hellier, Coel and Bellomo, Salvatore E. and Trifonov, Trifon and Chile, European Southern Observatory and Alarcon, Javier and Jenkins, Jon M. and Latham, David W. and Ricker, George and Seager, Sara and Vanderspeck, Roland and Winn, Joshua N. and Albrecht, Simon and Collins, Kevin I. and Csizmadia, Szilárd and Technology, Massachusetts Institute and Deeg, Hans J. and Esposito, Massimiliano and Fausnaugh, Michael and Georgieva, Iskra and Goffo, Elisa and Guenther, Eike and Hatzes, Artie P. and Howell, Steve B. and Jensen, Eric L. N. and Luque, Rafael and Mann, Andrew W. and Murgas, Felipe and Osborne, Hannah L. M. and Palle, Enric and Persson, Carina M. and Rowden, Pam and Rudat, Alexander and Smith, Alexis M. S. and Twicken, Joseph D. and Van Eylen, Vincent and Ziegler, Carl}},
  issn         = {{2397-3366}},
  language     = {{eng}},
  number       = {{6}},
  pages        = {{736--750}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Nature Astronomy}},
  title        = {{A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system}},
  url          = {{http://dx.doi.org/10.1038/s41550-022-01641-y}},
  doi          = {{10.1038/s41550-022-01641-y}},
  volume       = {{6}},
  year         = {{2022}},
}