Using data from NASA’s Transiting Exoplanet Survey Satellite (TESS) and several ground-based telescopes, astronomers have discovered and validated a two-planet system — composed of a super-Earth and a mini-Neptune — around the mid-type M dwarf star TOI-2096.
TOI-2096 is located around 48 parsecs (156.5 light-years) away in the constellation of Draco.
Otherwise known as TIC 142748283, the star hosts two massive exoplanets.
The inner planet is a so-called super-Earth approximately 1.2 times larger than Earth.
The outer world is a mini-Neptune about 1.9 times larger than our planet.
Named TOI-2096b and TOI-2096c, respectively, the planets likely reside in slightly eccentric orbits.
“Making an exhaustive analysis of the data, we found that the two planets were in resonant orbits: for each orbit of the outer planet, the inner planet orbits the star twice,” said Mathilde Timmermans, a doctoral student at the Université de Liège.
“Their periods are therefore very close to being a multiple of each other with about 3.12 days for TOI-2096b and about 6.38 days for TOI-2096c.”
“This is a very particular configuration, and it causes a strong gravitational interaction between the planets.”
“This interaction delays or accelerates the passage of the planets in front of their star and could lead to the measurement of the planetary masses using larger telescopes in the near future.”
While the size of planet TOI-2096b is compatible with a rocky composition, TOI-2096c is located in a particular parameter space where different formation models yield different predictions for its composition.
“These planets are of crucial importance given their sizes,” Timmermans said.
“The formation of super-Earths and mini-Neptunes remains a mystery today.”
“There are several formation models trying to explain it, but none fits the observations perfectly.”
“TOI-2096 is the only system found to date that has a super-Earth and a mini-Neptune precisely at the…
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