TESS discovers synchronized dance of earth-sized planets in the TOI-2096 system, offering clues to planetary formation

Scientists from the University of Liège and the CSIC have made an exciting discovery using NASA’s TESS telescope. They have detected a system consisting of two planets slightly larger than Earth, which orbit a cold star in a synchronized dance. This system, named TOI-2096, is located 150 light-years away from Earth.

The researchers used the transit method, which involves monitoring the brightness of stars to detect slight dimming caused by a planet passing in front of the star. While TESS is powerful in finding new planets, ground-based telescopes are needed to confirm and characterize the detected signals.

Ground-based telescopes, particularly those from the TRAPPIST and SPECULOOS projects led by the University of Liège, were used to observe the planets TOI-2096 b and TOI-2096 c, confirming their existence and providing further information. The analysis revealed that the two planets have resonant orbits, meaning that for every orbit of the outer planet, the inner planet orbits the star twice. Their orbital periods are close multiples of each other, with planet b orbiting every 3.12 days and planet c every 6.38 days.

This configuration results in a strong gravitational interaction between the planets, causing variations in the timing of their transits. This interaction could potentially allow future telescopes to measure the masses of the planets. The researchers estimate that planet b, the closest to its star, has a radius 1.2 times that of Earth, making it a “super-Earth.” Planet c has a radius 1.9 times that of Earth and 55% that of Neptune, placing it in the category of “mini-Neptunes.”

The sizes of these planets are particularly interesting because theoretical models predict fewer planets with radii between 1.5 and 2.5 times that of Earth. Hence, the discovery of TOI-2096 is significant in understanding the formation of super-Earths and mini-Neptunes, which remains a mystery in planetary science.

Additionally, the researchers highlight the potential for studying the atmospheres of these planets. The relative sizes of the planets in relation to their host star, along with the star’s brightness, make TOI-2096 one of the best candidates for detailed atmospheric studies using the upcoming James Webb Space Telescope (JWST). Such studies could provide insights into the formation mechanisms of these planets and confirm the presence of atmospheres around planets b and c.

In summary, the discovery of the TOI-2096 system with its resonant orbits and intriguing planet sizes offers a unique opportunity to investigate the formation of super-Earths and mini-Neptunes while providing prospects for studying their atmospheres in detail.

Source: University de Liege

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