Astronomers Have Found The First Naked Core Of A Planet In The Neptune Desert
Astronomers believe they have discovered the first exposed core of an exoplanet, according to an article in the journal Nature. It probably belonged to a gas giant that had lost its outer shell due to a collision with another planet or got too close to the mother star.
The internal structure of gas giants is still poorly understood. The difficulties faced by scientists due to the inability to directly look into the bowels of the planets, lead to the fact that even in the case of celestial bodies of the Solar system, there is a lot of uncertainty. Therefore, exoplanets that have undergone rare evolutionary processes can serve as a natural laboratory for testing modern theories and studying the internal structure of objects such as Saturn. Especially valuable from this point of view are the planets located in the "Neptune desert" — a region close to the star, where there are almost no planets the size of Neptune and the mass of about one-tenth of the mass of Jupiter.
David J. Armstrong and colleagues reported the discovery of one of these rare celestial bodies while analyzing observations made by the Transiting Exoplanet Survey Satellite (TESS) telescope. Studying the brightness drops of stars that appear during the passage in front of the sun of another planet, astronomers discovered an unusual object TOI 849b. It orbits a yellow dwarf 730 light-years away from Earth. A celestial body makes one revolution around the sun in 18 hours, and its surface temperature reaches 1800 Kelvins, but another thing is noteworthy.
Even though the radius of TOI 849b is close to that of Neptune (it is 3.4 earth's), its mass is almost three times that of the gas giant, making this object the densest Neptune ever discovered by scientists. Therefore, astronomers doubt that the celestial body has a vast gas shell — it is more like the Earth in type. However, models that would fully describe the structure of Earth-like planets of such masses do not exist today.
Computer simulations indicated two scenarios for the appearance of TOI 849b. One possibility suggests that we are looking at a planet that was once similar to Jupiter but lost its atmosphere as a result of some event, such as a collision with another celestial body, and now only the core remains. Another scenario suggests that it could be a failed gas giant that formed either with a shortage of hydrogen and helium or too late and failed to attract enough gas to form a shell.
To answer the question about the origin of TOI 849b, additional observations are needed to help determine the chemical composition of the celestial body. If scientists can figure out what substances the object's atmosphere is made of, it will allow them to guess what the object's interior might look like.
In the past, astronomers have discovered another object from the "Neptune desert." It is located in the K-dwarf system and makes one revolution around the star in 1.33 earth days.