학술논문
A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system
Document Type
Working Paper
Author
Serrano, Luisa Maria; Gandolfi, Davide; Mustill, Alexander J.; Barragán, Oscar; Korth, Judith; Dai, Fei; Redfield, Seth; Fridlund, Malcolm; Lam, Kristine W. F.; Díaz, Matías R.; Grziwa, Sascha; Collins, Karen A.; Livingston, John H.; Cochran, William D.; Hellier, Coel; Bellomo, Salvatore E.; Trifonov, Trifon; Rodler, Florian; Alarcon, Javier; Jenkins, Jon M.; Latham, David W.; Ricker, George; Seager, Sara; Vanderspeck, Roland; Winn, Joshua N.; Albrecht, Simon; Collins, Kevin I.; Csizmadia, Szilárd; Daylan, Tansu; Deeg, Hans J.; Esposito, Massimiliano; Fausnaugh, Michael; Georgieva, Iskra; Goffo, Elisa; Guenther, Eike; Hatzes, Artie P.; Howell, Steve B.; Jensen, Eric L. N.; Luque, Rafael; Mann, Andrew W.; Murgas, Felipe; Osborne, Hannah L. M.; Palle, Enric; Persson, Carina M.; Rowden, Pam; Rudat, Alexander; Smith, Alexis M. S.; Twicken, Joseph D.; Van Eylen, Vincent; Ziegler, Carl
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Subject
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Abstract
It is commonly accepted that exoplanets with orbital periods shorter than 1 day, also known as ultra-short period (USP) planets, formed further out within their natal protoplanetary disk, 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 $\sim$ 13 hours, a mass of 1.42 $\pm$ 0.18 M$_{\oplus}$, a radius of $1.166^{0.061}_{-0.058}$ R$_{\oplus}$, and a mean density of 4.89$^{+1.03}_{-0.88}$ gcm$^{-3}$. Via Doppler spectroscopy, we discovered that the system hosts three outer planets on nearly circular orbits with periods of 6.6, 26.2, and 61.3d and minimum masses of 5.03 $\pm$ 0.41 M$_{\oplus}$, 33.12 $\pm$ 0.88 M$_{\oplus}$ and 15.05$^{+1.12}_{-1.11}$ 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 Gyrs, starting from an initial orbit of 0.02au. TOI-500 is the first four planet system known to host a USP Earth analog whose current architecture can be explained via a non-violent migration scenario.
Comment: Published on Nature Astronomy (April 28th, 2022)
Comment: Published on Nature Astronomy (April 28th, 2022)