2023-05-21 00:12:27
Volcanism is a more or less usual phenomenon here on Earth. But it is not so common in the Solar System. Yes, many worlds have structures that in the past expelled material from the depths; but few do right now. For example, on Io, one of Jupiter’s moons, giant columns of smoke from volcanic activity have been seen; or Triton, Neptune’s satellite, or Enceladus, Saturn’s moon, have cryovolcanoes, which do not ‘vomit’ molten rock, but rather water and gases. A couple of months ago signs of recent volcanic activity on Venus were reported. But is this phenomenon common outside of our cosmic neighborhood?
Now, an international group, in which researchers from the Instituto de Astrofísica de Canarias (IAC) participate, has found an exoplanet that could be covered in volcanoes. baptized as LP 791-18 d, is about 90 light years away from Earth, and has a size and mass slightly greater than our planet. According to the authors, this world could experience volcanic eruptions as frequently as Io. The study has just been published in ‘Nature‘.
It is not an unknown star system: astronomers had already discovered two other neighboring worlds, LP 791-18 b y LP 791-18 c, which orbit around the red dwarf LP 791-18. Inner planet b is about 20 percent larger than Earth and its companion c is about 2.5 times our size and almost 9 times the mass of our world.
These data are not trivial: during each orbit, the planet c and the newly discovered d pass very close to each other. As the former is more massive than the latter, each time they pass close by, their gravity affects the surface of the other (like tides and the Moon), producing a gravitational tug that causes their orbit to be somewhat elliptical and, furthermore, planet d is slightly deformed.
“These deformations can create enough internal friction to substantially heat the interior of the planet and produce volcanic activity on its surface,” explains Merrin Peterson, a graduate student at the University of Montreal (UdeM) who led the study, in a statement. In fact, Jupiter and some of its moons affect Io in a similar way.
Liquid water could exist on its surface
Planet d lies at the inner edge of the habitable zone, the range of distances from a star in which liquid water could exist on a planet’s surface. If the planet is as geologically active as the research team suspects, it could support an atmosphere. Temperatures could drop low enough on the night side of the planet for water to condense on the surface.
“LP 791-18 d has one side constantly facing its star,” says Björn Benneke, a UdeM researcher who co-led the study. The dayside would probably be too hot for liquid water to exist on the surface, but the amount of volcanic activity we suspect occurs across the planet could sustain an atmosphere, making condensation of water possible on the nightside.”
“This study is very revealing since one of the big questions in astrobiology, the field that studies the origins of life on Earth and beyond, is whether tectonic or volcanic activity is necessary for life,” says Felipe Murgas. , IAC researcher and co-author of the article. “In addition to potentially providing an atmosphere, these processes could agitate materials that would otherwise sink and become trapped in the crust, including those that we think are important for life, such as water or carbon,” adds Enric Pallé, a researcher. of the IAC who also participated in the study.
Scientists discovered and studied the planet using data from NASA’s Transiting Exoplanet Survey Satellite (TESS) and the Spitzer Space Telescope, as well as from a suite of ground-based observatories, including observations with MuSCAT2 installed on the Carlos Sánchez Telescope. Spitzer’s observations of the system were among the last the satellite collected before its decommissioning in January 2020. Planet c has already been approved for observation by the James Webb Space Telescope, and the team expects the planet to d be an outstanding candidate for the mission’s atmospheric studies.
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