Scientists: probable 'ocean planet' discovered in the Draco constellation

An international team of experts led by the University of Montreal has recently announced the discovery of TOI-1452 b – an exoplanet orbiting one of two small stars in a binary system located in the Draco constellation, approximately 100 light-years from the Earth. The observations and subsequent analyses revealed that this planet is slightly greater in size than the Earth and is located at a distance from its star where its temperature could allow for liquid water to exist on its surface, leading scientists to suspect that it could be an “ocean planet” covered completely by a thick layer of water, just like some of Jupiter’s and Saturn’s moons.

The researchers discovered this planet with the help of NASA’s space telescope TESS and follow-up ground observations with the high-resolution PESTO camera. The host star TOI-1452 is much smaller than our Sun and is one of two similarly-sized stars in the binary system where the new planet was discovered. Although the TESS telescope sees the two stars as a single point of light (due to the small distance separating them), PESTO’s resolution was high enough to distinguish the two objects, and confirm that the exoplanet is orbiting TOI-1452.

In order to determine the planet’s mass, the astronomers then observed the system for over 50 hours with SPIRou, an instrument installed on the Canada-France-Hawaii Telescope in Hawai’i, and estimated that the planet has a mass nearly five times larger than that of the Earth. While this exoplanet is most likely rocky, like the Earth, its radius, mass, and density suggest that it may be largely covered by water, which makes up to 30 percent of its mass (compared to the less than one percent of water making up the mass of the Earth).

“TOI-1452 b is one of the best candidates for an ocean planet that we have found to date,” explained study lead author Charles Cadieux, a doctoral student in Astrophysics at the University of Montreal. “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.”

In the near future, the scientists aim to use the newly constructed James Webb Space Telescope – the most performant telescope to date – in order to clarify the nature and features of this fascinating planet. “Our observations with the Webb Telescope will be essential to better understanding TOI-1452 b,” said co-author René Doyon, an expert in exoplanets at the University of Montreal. “As soon as we can, we will book time on Webb to observe this strange and wonderful world.” 

A detailed description of this planet was published in the Astronomical Journal.

Image Credit: Benoit Gougeon, Université de Montréal

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By Andrei Ionescu, Earth.com Staff Writer