Serrano, Luisa Maria;
Gandolfi, Davide;
Mustill, Alexander J;
Barragan, Oscar;
Korth, Judith;
Dai, Fei;
Redfield, Seth;
... Ziegler, Carl; + view all
(2022)
A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system.
Nature Astronomy
, 6
pp. 736-750.
10.1038/s41550-022-01641-y.
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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 1.166−0.058+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.
| Type: | Article |
|---|---|
| Title: | A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1038/s41550-022-01641-y |
| Publisher version: | https://doi.org/10.1038/s41550-022-01641-y |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Astronomy and astrophysics, Exoplanets |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10150029 |
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