2023-05-17 15:57:05
According to the first observations, this planet called LP 791-18 d which is located in the southern constellation of the Cup would be temperate and probably covered with volcanoes. The exoplanet is located very close to its star which is much smaller and less bright than the Sun.
The planet is at the inner limit of the temperate zone (or habitable
), that is, the distance from its star where liquid water could be on its surface. The temperature on LP-791-18 d is only slightly higher than that of Earth. If it is as geologically active as the Montreal team suspects, it could retain an atmosphere and, under certain conditions, temperatures could even drop enough on the night side of the planet for water to condense on its surface
.
« It is similar to Io, the moon of Jupiter, the most volcanic object in the solar system. »
Thanks to data collected by NASA’s TESS telescope, astronomers had determined as early as 2019 that there was a system of at least two planets around the star LP 791-18:
- With less than 1.5 Earth masses, LP 791-18 b is an Earth-like planet, like our planet, Mercury, Venus and Mars in our system.
- With more than 10 landmasses, LP 791-18 c is an icy giant, a planet composed mostly of volatile materials like water, ammonia and methane, and shrouded in a dense atmosphere of hydrogen and helium. , like Uranus and Neptune.
One last mission for Spitzer
But Professor Benneke and one of his students were unsure whether the TESS telescope, which is excellent at finding large exoplanets, was powerful enough to find small Earth-sized planets around the star.
That’s when they contacted the team at NASA’s end-of-life Spitzer Telescope, which was making its final observations at the time. According to the professor, the star system LP 791-18 represents a good opportunity to learn more about small rocky planets, much like the TRAPPIST-1 system, which hosts seven Earth-sized planets.
« NASA was offered to observe the star continuously for 120 hours, even though the later periods had already been assigned. They accepted and we had an extraordinary opportunity. »
The Montreal team thus used the telescope to detect the transit of planets in front of the star.
« We saw the transits of the two other planets, but also that of another which was not known. So there are at least three planets in this system. »
791-18d is extraordinary”,”text”:”The discovery of exoplanet LP791-18d is extraordinary””>The discovery of exoplanet LP 791-18 d is extraordinary
enthuses Professor Björn Benneke.
The teacher explains that in our solar system, we know that Io is similarly affected by Jupiter and its other moons, and this world is the most volcanic we know
.
« The prospect of geological activity and the presence of volcanic activity make it an important object to better understand the formation and evolution of terrestrial planets. »
791-18d”,”text”:”The gravitational pull of the more massive neighboring planet would lead to internal heating and volcanic eruptions on LP791-18d””>The gravitational pull of the more massive neighboring planet would cause internal heating and volcanic eruptions on LP 791-18 d
thinks Professor Benneke.
« The friction caused by the presence of a planet which passes very close increases the temperature of the interior of the detected planet, and would cause the presence of an ocean of magma under the surface. »
Landmarks
- It was on October 6, 1995 that Swiss scientists Michel Mayor and Didier Queloz, from the Geneva Observatory, announced the discovery of 51 Pegasi b, the first exoplanet detected in orbit around a sun-like star.
- Since then, astrophysicists have identified no less than 5,347 exoplanets (source: NASA, May 16), and 9,618 others are in the process of being confirmed.
In Webb’s Lens
It had already been agreed that the James Webb telescope would observe planet c, the largest in the system, as part of the Canadian NEAT program, but planet d will also be a prime target.
As the star is very small in size – barely larger than Jupiter – it should be possible to detect the atmosphere of this exoplanet, if it has one, using the James Space Telescope. Webb.
The study of the planet LP 791-18 d will undoubtedly advance not only astronomy, but also many other scientific fields, including geology, earth sciences, atmospheric sciences and perhaps be astrobiology.
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