Bare core of a Jupiter-like planet discovered

Bare core of a Jupiter-like planet discovered
University of Warwick/Mark Garlick

About 730 light-years from Earth, far away on a galactic scale, researchers have found a mysterious planet orbiting a sun-like star. The distance from the main star is very close, large, and dense. No other planet such as this has been found in the solar system, but also in the universe far away.

Named TOI-849b, this scorching planet is the heaviest rock planet ever observed and has a mass of as much as 40 earth. If the mass is so large, it is supposed to be a giant gas planet like Jupiter, but for some reason, there is almost no atmosphere. The current theory of planet formation does not explain the formation process of this celestial body.

“It is very difficult to create a planet as heavy and dense as the TOI-849b. It’s usually going to be a giant gas planet,” David Armstrong, an exoplanet researcher at the University of Warwick, told The paper, which they reported on the findings, was published in the journal Nature on July 1.

“Something happened that was out of the standard formation process.” This is what Mr. Armstrong and his thoughts are. The planet was supposed to be a huge gas planet above Jupiter, but for some reason only the exposed cores (nuclei) without air remained.

“These objects advance theory and make the study of exoplanets and planetary sciences very interesting,” said Rabbit Helled of the University of Zurich, Switzerland, who is co-author of the paper.

“It’s a very strange object!” What surprises me is Jonathan Fortney, director of the Institute for Extraterrestrial Planets at the University of California, Santa Cruz. He is not involved in the study. “But I don’t know for sure what it tells me.”

Thousands of planets have been found in the galaxy’s stars in the last decade. Most of them were the Jupiter-shaped giant gas planet “Hot Jupiter”, which orbits in the immediate vicinity of the main star, or “Super-Earth”, a rocky planet larger than Earth and smaller than Neptune. However, THE TOI-849b does not apply to either.

The planet was discovered by NASA’s Space Telescope, the Transit Exoplanet Search Satellite (TESS). TESS has observed 200,000 bright stars near the solar system. If a planet crosses in front of a star, the light from the star temporarily darkens slightly, so it is enough to know the planet’s existence.

This observation method, called the transit method, showed that the TOI-849b circled around the main star in 18 hours. Because the distance from the main star is very close, the surface temperature of the planet can be as high as about 1500 degrees Celsius.

TESS observations show that the planet is about 3.4 times the diameter of Earth and 0.85 times that of Neptune. If it is only the size, it can be called “Hot Neptune”, but the mass is different as described below. Most of the exoplanets orbiting very close to the star are hot jupiter or much smaller super earths, and hot neptune has not been found. It is called “Hot Neptune Desert” in the sense that it is an area where hot neptune is not found.

“We can’t really find a planet in this area as mass as Neptune,” Fortney said.

The toi-849b gravity-induced glare was observed using the High-Precision Gaze Velocity Exoplanet Exploration Device (HARPS) by the La Siya Observatory in Chile, and found that the planet was more than twice as massive as Neptune. Considering the size, it can be seen that the density of the TOI-849b is very high. There may be a thin layer of atmosphere consisting of hydrogen and helium, but it is much less than the amount of atmosphere that a planet with this mass is supposed to have.

“This planet is thought to be made of metal, silicates, water, and a very small atmosphere,” Heredo said.