(ORDO NEWS) — An international team of astronomers has discovered a mysterious planet 138 light-years from Earth that may be in the process of transformation.
Scientists believe that it is gradually turning into a super-earth, that is, into a solid and water world similar to the Earth.
Briefly, Science Alert talks about him. The new exoplanet has been named HD-207496b.
Observations of it showed that its mass is 6.1 times the mass of the Earth, and its radius is 2.25 of the radius of our planet. So now it’s a giant planet.
However, the data obtained allowed scientists to suggest that the new world is in the process of transformation and, perhaps, is gradually shrinking to eventually turn into a super-Earth.
So called exoplanets, similar in their characteristics to the Earth. The newly opened world could have either a gaseous atmosphere, a global water ocean, or a mixture of both, the researchers note.
If these assumptions are confirmed, then HD-207496b will be the missing link. The fact is that there is a gap in studies of the masses of rocky and gaseous planets.
To date, astronomers have discovered about 5,300 worlds outside the solar system, as well as twice as many exoplanet candidates whose existence has yet to be confirmed.
Analysis of information about new worlds allows us to identify some trends.
One of the mysteries is that there is an inexplicable “lack of exoplanets” with masses 1.5-2 times that of the Earth and with orbits shorter than 100 days.
The reasons for this gap are not entirely clear to scientists. There is an idea that below a certain critical threshold, an exoplanet simply does not have enough mass to hold its atmosphere with the help of gravity.
As a result, atmospheric gas evaporates under the influence of radiation from the parent star. The discovery of a new world may provide clues to the mystery of this process.
In particular, the researchers used the HARPS method, which made it possible to measure the mass and radius of the planet, as well as calculate its orbit, the movement of which is only 6.44 days.
The planet rotates around the dwarf star HD-207496. She is relatively young, her age is only about 520 million years.
The density of the exoplanet turned out to be much less than that of the Earth. This means that, in its current composition, the HD-207496b world is not completely solid.
“From simulations of the internal structure of the planet, we found that the planet has either a water-rich shell, or a gas-rich shell, or a mixture of both,” the researchers write in their paper.
“Evaporation simulations show that if an exoplanet has a gas-rich atmosphere of hydrogen and helium , then this state is temporary: the star will completely expose the exoplanet within 520 million years.
It is also possible that the atmosphere has already evaporated, and HD-207496b is already a bare ocean world.In general, we expect the planet to have both water and hydrogen-helium shell.
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