A terrestrial planet 90 light years away that may be covered in volcanoes

MADRID, 17 May. (EUROPA PRESS) –

A third terrestrial-type planet has been discovered around the red dwarf star LP791-18, located just 90 light-years away, cwhose gravitational interaction with the most massive planet in the system can generate intense volcanic activity.

With the finding, published in Nature, the system is formed by the super-Earth LP791-18b, of a rocky type and with a mass 20% greater than that of Earth, the mini-Neptune LP791-18c, a gaseous planet with about nine times the mass of Earth. Earth mass, and a new third Earth-like planet, LP791-18d, whose orbit around the star is dangerously close to mini-Neptune. This produces a gravitational interaction that slightly deforms the newly found planet and heats its interior, possibly generating widespread volcanic activity along its surface.

“The planet LP791-18d shows what is known as tidal lock, which means that the same side is constantly looking at its star,” says Björn Benneke, a researcher at the University of Montreal who is leading the study. The dayside is probably too hot for liquid water to exist on the surface, but the amount of volcanic activity that we suspect occurs across the planet could sustain an atmosphere, which could allow water to condense on the night side.”

During each orbit, mini-Neptune c and terrestrial planet d pass very close to each other. Each approach produces a gravitational tug of the first on the second, causing its orbit to trace a somewhat elliptical path in which it deforms slightly each time it revolves around the star. These deformations can create enough internal friction to heat the interior of the planet and produce volcanic activity, a phenomenon similar to that exerted by the planet Jupiter on its satellite Io, which holds the record for volcanic activity in the entire Solar System.

Planet d lies at the inner edge of the habitable zone, the region around a star where pressure and temperature conditions would allow liquid water to exist on a planet’s surface. If the newly found planet is as geologically active as the science team suspects, it could maintain an atmosphere and temperatures they could sink low enough on the night side of the planet for water to condense on the surface.

“While the Université de Montréal team was analyzing observations with the Spitzer telescope (NASA), our team discovered the signal corresponding to the planet LP791-18d using proprietary planet search software,” he says. it’s a statement Francisco J. Pozuelos, researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) who participates in the work. By processing the data from the TESS space telescope, our algorithm detected the signal, which had gone undetected, and we began an observation campaign with ground-based telescopes using the SPECULOOS network of telescopes and coordinating with the other teams involved in the discovery.”

A big open question in astrobiology, the field that studies the origins of life, is whether tectonic or volcanic activity is necessary for the emergence of life: in addition to providing an atmosphere, these processes could move materials that would otherwise sink. and would be trapped in the crust, including those considered important to life, such as carbon.

“Planet c has already been approved for observation with the recently launched James Webb Space Telescope, and we believe that planet d is also an outstanding candidate for atmospheric studies“, concludes Francisco J. Pozuelos (IAA-CSIC).