Astronomers find new, nearby planet that is entirely covered in water

Scientists are on trail of what may be true alien water world - an exoplanet with global ocean

Jon Kelvey
Friday 26 August 2022 07:11 BST
Related: Galaxy’s Youngest Exoplanet Offers Insight Into How Planets Form
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Astronomers have discovered a nearby exoplanet that may prove to be the first such world covered in water.

TOI-1452 b is an exoplanet slightly larger and more massive than Earth about 100 light years away from our planet in the Draco constellation. In a paper published Wednesday in The Astronomical Journal, researchers from the University of Montreal determine that the mass of the planet suggests it is largely made up of something less dense than rock, but denser than gas — a potential sign of a global ocean.

“TOI-1452 b is one of the best candidates for an ocean planet that we have found to date,” University of Montreal astrophysics PhD student Charles Cadieux said in a statement. “Its radius and mass suggest a much lower density than what one would expect for a planet that is basically made up of metal and rock, like Earth.”

TOI-1452 b first came to astronomers’ attention through Nasa’s Transiting Exoplanet Survey Satellite, or Tess spacecraft, which studies distant stars for telltale dips in their light that signify an exoplanet passing in front of, that is transiting, the star. Tess data suggested the existence of an exoplanet, but the observation was not definitive.

The star TOI-1452 b orbits is part of a binary star system, and Tess does not possess the power to resolve the individual stars in that system. The University’s Observatoire du Mont-Mégantic (OMM) observatory, however, along with new analytic methods, was able to confirm that TOI-1452 b exists.

“The OMM played a crucial role in confirming the nature of this signal and estimating the planet’s radius,” Mr Cadieux said. “This was no routine check. We had to make sure the signal detected by TESS was really caused by an exoplanet circling TOI-1452, the largest of the two stars in that binary system.”

An instrument installed on the Canada-France-Hawaii Telescope in Hawai’i then measured the planet’s mass.

Unlike Earth, which is a mostly rocky and metallic planet with water covering around 70% of its surface, TOI-1452 b appears to be made largely, but not entirely, of water, with about 30% of its mass coming from the liquid. That’s a sort of deep global ocean more akin to the deep waters believed to lurk beneath the icy crust of Saturn’s moon Enceladus than the oceans of Earth; water makes up less than 1% of our planet’s mass.

Exoplanets are located outside of our solar system.

It’s still not certain that TOI-1452 b is an ocean world, and just what that might mean for the chances of discovering alien life in its waters, but the researchers note that the James Webb Space Telescope should soon be able to help penetrate the mystery of this strange new watery world.

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