Exoplanets & Exomoons

Teegarden’s Star Revisited: A Nearby Planetary System With At Least Three Planets

By Keith Cowing
Status Report
February 5, 2024
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Teegarden’s Star Revisited: A Nearby Planetary System With At Least Three Planets
Planetary system architectures in comparison. Left panel: Semi-major axes in planetary systems in comparison. For Teegarden’s Star we show two possible configurations: the three planets as fit by our preferred model and a hypothetical configuration (labeled as Teegarden (h)) with the three planets, the candidate at 7.7 d (light blue) as well as a purely hypothetical planet between planets c and d (light gray). The size of the plot symbols in the left panel are scaled assuming a constant planet density using the masses from Table 4 and G.2. Right panel: Mutual Hill separations in planetary systems in comparison. The light blue line indicates the mutual Hill radius above which the orbital crossing time is larger than 109 orbits. — astro-ph.EP

The two known planets in the planetary system of Teegarden’s Star are among the most Earth-like exoplanets currently known. Revisiting this nearby planetary system with two planets in the habitable zone aims at a more complete census of planets around very low-mass stars.

A significant number of new radial velocity measurements from CARMENES, ESPRESSO, MAROON-X, and HPF, as well as photometry from TESS motivated a deeper search for additional planets. We confirm and refine the orbital parameters of the two know planets Teegarden’s Star b and c. We also report the detection of a third planet d with an orbital period of 26.13+-0.04 d and a minimum mass of 0.82+-0.17 M_Earth.

A signal at 96 d is attributed to the stellar rotation period. The interpretation of a signal at 172 d remains open. The TESS data exclude transiting short-period planets down to about half an Earth radius. We compare the planetary system architecture of very low-mass stars.

In the currently known configuration, the planetary system of Teegarden’s star is dynamically quite different from that of TRAPPIST-1, which is more compact, but dynamically similar to others such as GJ 1002.

S. Dreizler, R. Luque, I. Ribas, V. Koseleva, H. L. Ruh, E. Nagel, F. J. Pozuelos, M. Zechmeister, A. Reiners, J. A. Caballero, P. J. Amado, V. J. S. Béjar, J. L. Bean, M. Brady, C. Cifuentes, M. Gillon, A. P. Hatzes, Th. Henning, D. Kasper, D. Montes, J. C. Morales, C. A. Murray, E. Pallé, A. Quirrenbach, A. Seifahrt, A. Schweitzer, J. Stürmer, G. Stefánsson, J. I. Vico Linares

Comments: Astronomy & Astrophysics, accepted; 21 pages, 18 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2402.00923 [astro-ph.EP] (or arXiv:2402.00923v1 [astro-ph.EP] for this version)
Submission history
From: Stefan Dreizler
[v1] Thu, 1 Feb 2024 17:35:25 UTC (13,431 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻