Although it is – for cosmic conditions – close to us, it has been elusive for decades. TOI-1452b, the name of an exoplanet that has been discovered by scientists, orbits one of the stars in a binary system 100 light-years away from the solar system. Researchers from the University of Montreal reported that its size and mass could indicate that a large part of its surface is covered with water.
Exoplanets are planets outside the Solar System orbiting a star other than the Sun we know. This particular one is 100 light-years away and seems to be the best candidate for the second Earth title so far. Scientists who say so have named it TOI-1452b, and they said measurements suggest that its entire surface may be covered by the ocean.
Researchers have speculated for years whether such worlds are possible, but have yet to find them.
To study the atmosphere of an exoplanet in more detail, scientists want to continue observing it with the James Webb Space Telescope (JWST). But the preliminary results, published in The Astronomical Journal, are already intriguing.
“This study reports the discovery and characterization of the exoplanet TOI-1452b,” said Charles Cadieux, a researcher at the University of Montreal. – The results of our modeling and the fact that the planet is exposed to moderate radiation make TOI-1452b a world of water.
Two telescopes were combined
Why had she avoided observation before? The exoplanet was found orbiting one of a pair of small, vague red dwarfs separated by just 97 AU. It is so little that the two stars seem to be one.
However, the TESS telescope is sensitive enough to detect regular faint dips in the star’s light that suggest the presence of TOI-1452b. Such transitions of an exoplanet against the background of the star are known as transits. To confirm their assumptions, the researchers used a highly sensitive instrument from the Mont Mégantic Observatory in Canada, designed specifically to detect transits.
Observations from both telescopes revealed that, indeed, this part outer space there is an exoplanet orbiting one of the stars in a binary system.
TOI-1452b relative to Earth
By looking at how much light the star emits and then how it gets darker as the exoplanet passes in front of it, scientists were able to estimate its potential size. TOI-1452b, they say, could be relatively small – 1,672 times the size of Earth. This size classifies it as a super-earth – extrasolar, rocky planets that do not necessarily have the same conditions as on Earth.
Its orbiting time is only 11 days, which seems crazy from the perspective of our planet. But because its star is cooler and darker than the Sun, the exoplanet is right in the center of the star’s moderate influence zone. And in the perfect spot: not so far that its water would freeze, nor so close that it would turn to gas.
Candidate for an ocean planet
After examining the planet, researchers decided to find out more about its star. They were particularly interested in the so-called radial velocity – the way it moves under the influence of the gravity of an exoplanet. Every two bodies in the system orbit around a common center of gravity.
This movement is revealed by changes in the star’s light. Moreover, they allow astronomers to calculate the mass of an orbiting body by determining the strength of the motion. In this way, it was possible to calculate that TOI-1452b has a mass 4.82 times greater than our planet.
And here it gets really interesting
Once we know the size and mass of an object, we can estimate what its average density is. In the case of TOI-1452b, it is 5.6 grams per cubic centimeter. This is slightly more than the Earth, which is 5.5 grams per cubic centimeter. However, the researchers reported that an Earth-like density for an object that has a greater mass indicates that the exoplanet consists of lighter material.
“TOI-1452b is one of the best candidates for an oceanic planet we have found so far,” says Cadieux. “Its size and mass suggest a much lower density than would be expected for a planet of metal and rock,” he adds.
By modeling the interior of the building, researchers found that 30 percent of its mass could be water. That’s a lot – for comparison, in the case of the Earth, water is less than 1 percent of its mass. Therefore, the composition of TOI-1452b in this respect seems closer to Europe – one of the moons of Jupiter or Enceladus – Saturn’s natural satellite.
From the perspective of space
However, with current terrestrial technology, it is difficult to pinpoint exactly what the TOI-1452b is made of. This is where JWST comes in – the Webb Telescope. As the exoplanet keeps passing between us and its light source, scientists want to look at the object’s potential atmosphere, if it has one at all. The telescope should be sensitive enough to detect the difference in this light, giving scientists a chance to determine what the atmosphere of an exoplanet consists of.
“Our observations with the Webb Telescope will be crucial to a better understanding of TOI-1452b,” said astronomer René Doyon of the University of Montreal. “As soon as we can, we’ll reserve Webb to observe this strange and wonderful world,” he concluded.
Main photo source: Benoit Gougeon, Université de Montréal.