University of Montreal researchers discover an ocean planet in a binary star system 100 light-years away.
Frankfurt – In the movie "Interstellar," the first planet the spaceship "Endurance" heads to in search of a replacement for Earth, which has become inhospitable, turns out to be an ocean planet – covered all over with water. Researchers of our time do not yet have to go in search of a new home for mankind. Intensive lookout for exoplanets outside of our solar system they hold nevertheless and use for it data of the modern space telescopes.
A team of researchers from the University of Montreal (Canada) has now discovered a celestial body 100 light-years away that could be very close to the fictional ocean planet from "Interstellar". It bears the designation TOI-1452 b and orbits one of two relatively small stars of a double star system in the constellation Dragon. The scientists describe their discovery in the Astronomical Journal.
Exoplanet found is probably an ocean planet
While the two stars are smaller than our sun, the water-rich exoplanet is about 70 percent larger than Earth and also has about five and a half times as much mass. What's particularly interesting is that TOI-1452 b orbits its star at a distance that allows for a temperature on its surface that is neither too hot nor too cold to host liquid water. The latter is considered a prerequisite for life. The researchers even suspect that the planet is completely covered with a thick layer of water, which means that it is an ocean planet.
TOI-1452 b was detected by Nasa's Tess space telescope, which scans the sky for planetary systems near our own. The telescope's signal showed a slight decrease in the brightness of the slightly larger star in the binary system every eleven days. Such a regular break is an indication of a possible planet in orbit. TOI-1452 b was finally detected with the help of the Observatoire du Mont-Megantic, a telescope developed by the Canadian researchers and equipped with a camera that provides high-resolution images.
There is much more water on the planet found than on Earth
"It played a crucial role in confirming the nature of this signal and estimating the radius of the planet," explains astronomer Charles Cadieux of the University of Montreal, "We had to make sure that the signal detected by Tess was really caused by an exoplanet."
The planet TOI-1452 b differs strongly from our homeland. Even though Earth is often called the Blue Planet because about 70 percent of its surface is ocean, it is "essentially a very dry planet," according to a University of Montreal statement. In fact, water is only a "negligible fraction of the mass – less than one percent". Two University of Toronto scientists who specialize in modeling the inner workings of exoplanets concluded that TOI-1452 b, on the other hand, is likely to have water accounting for up to 30 percent of the planet's mass.
Other ocean planets are composed mainly of water vapor
Also in our solar system there are celestial bodies with a presumably large portion of water in the mass. However, these are not planets, but Jupiter's moons Ganymede and Callisto and Saturn's moons Titan and Enceladus. Contrary to what is assumed for TOI-1452 b, its surface is not covered with liquid water, but probably with ice to a large extent.
Exoplanets have already been discovered, which could be similar to TOI-1452 b ocean planets. These include planet GJ1214b, tracked down by the Hubble telescope in 2012, which orbits a red dwarf star 40 light-years from Earth and likely has only a small rocky core and a lot of water. Observations revealed that its atmosphere is likely to be composed mainly of water vapor. Ocean planets are also suspected in the star system Kepler-62, 1200 light-years away.
Liquid water does not guarantee the possibility of life on a planet
Even though liquid water is considered a prerequisite for life, that doesn't automatically mean planets that harbor plenty of it are life-friendly places. For example, a study published in 2016 by researchers from Belgium, Germany, Austria and France suggests that too much water may actually be a hindrance to the emergence of life. If too much covers the planet, the pressure at the bottom of the ocean rises sharply. The consequence: "High pressure ice" is formed, which has a particularly dense crystal form and is deposited on the sea bottom. However, it becomes a barrier and thus separates the ocean floor from the atmosphere, so that exchange is no longer possible. However, in order for life to develop, both minerals from the bottom of the oceans and organic matter from the atmosphere are needed.
The exoplanet TOI-1452 b will now be observed more closely with the new James Webb space telescope to better assess its properties. "As soon as we can," says Rene Doyon, director of the Observatoire du Mont-Megantic at the University of Montreal, "we will book time on Webb to observe this strange and wonderful world."(Pamela Dorhofer)