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Astronomers Have Discovered The Heaviest Earth-Like Planet

Astronomers Have Discovered The Heaviest Earth-Like Planet

Astronomers have found the largest stony exoplanet known to science in the constellation of Pechi: it is 39 times heavier than the Earth. This planet is the naked core of a gas giant, from which its star "stripped" all the outer shells. The description of the discovery is available in the scientific journal Nature.

"The planet TOI 849b is the heaviest Earth-like world, with a density equivalent to that of our planet. We assume that it was originally similar to Jupiter; it was covered with a large amount of helium and hydrogen. Their absence suggests that we are dealing with the naked core of the planet," commented one of its authors, a planetary scientist from the University of Warwick (UK) David Armstrong.

Over the past few years, astronomers have discovered more than a thousand exoplanets and several thousand candidates for this role. Most of them belong to the so-called hot Jupiters-planets with a mass similar to Jupiter, but which are located much closer to the star: even closer than Mercury is to the Sun.

However, scientists are increasingly finding smaller planets that are comparable in size to the Earth. The growing number of potential duplicates of our planet makes astronomers wonder whether life can exist on them.

Three years ago, astronomers who worked with the Kepler space telescope found that relatively small exoplanets can be divided into two distinct groups-super-earths, whose mass exceeds the earth's by no more than 10 times, and mini-Neptunes, their mass is ten times greater than that of our planet.

These planets are radically different from each other in appearance. The former is similar in physical properties, appearance and structure to enlarged copies of the Earth, while the latter are ocean worlds or "dwarf" gas giants. Small planets that can not be attributed to any of these types have not been found in recent years, so scientists have called the gap between them "Neptune Desert."

Studying images from the Tess space Observatory, Armstrong and his colleagues discovered the most unusual example of planets from this desert so far. To find such planets, this telescope tracks periodic dimming in the glow of stars. This dimming may occur since the planet during rotation around the star temporarily "blocks" its light for the telescope.

Largest Earth-like planet

The attention of astrophysicists was drawn to the planet TOI 849b, which TESS recently discovered next to a sun-like star in the constellation of Furnace. The system of this star is 700 light-years from Earth. TOI 849b is located at a relatively short distance from the star and orbits it in just 18 hours. Because of this, the temperature on its surface should be more than 1800 Kelvins (1526 °C).

Tess data showed that the planet's radius was about 3.5 times that of Earth, which is why scientists first ranked it among the typical "hot mini-Neptunes." After tracking TOI 849b with the HARPS spectroscope, which is mounted on one of the telescopes of the European Southern Observatory in Chile, Armstrong and his team found that these representations were erroneous.

This instrument can discover exoplanets and study their properties, tracking how gravitational interactions between a star and its satellites affect the structure of the star's spectrum. Thanks to this approach, unlike the methods of Kepler and TESS, astronomers can very accurately calculate the mass and density of exoplanets.

As a result, TOI 849b was found to be about 39 times heavier than Earth. This means that its density is at least 5.2 g/cm 3. This indicator is almost identical to the density of our planet. This rules out that TOI 849b could be an ocean planet or a gas giant.

As scientists suggest, this planet is a "naked" core of a gas giant the size of Jupiter, which either lost its gas shells as a result of gravitational interactions with a star or a collision with another planet or did not have time to form them during the birth of the star system TOI 849.

How exactly this happened, astronomers do not yet know. However, the discovery of TOI 849b itself suggests that such worlds may exist. Through their study, astronomers will be able to understand how the bowels of such giant Earth-like planets are arranged and what exotic forms of matter may be present in their Central regions with high pressures and temperatures. They will become a new testing ground for theories of planet formation, Armstrong and his colleagues conclude.