An international team of scientists from Japan and Europe announced the discovery of an ultra-dense exoplanet. It may be a remnant of a larger world.
The discovery was made while examining data collected by the Kepler telescope during the extended K2 mission. It managed to detect periodic changes in the brightness of a sun-like star located 750 light-years away from Earth. They are caused by the transits of an exoplanet orbiting around it, designated K2-360 b. Its diameter is 1.6 times larger than the diameter of the Earth, and its orbital period is 21 hours.
In the course of subsequent spectrometric observations, scientists were able to determine the mass of this exoplanet, as well as detect another exoplanet (it was designated K2-360 s) in this system, which was not transiting. Its orbital period is 9.8 days.
It turns out that the mass of the inner exoplanet is 7.7 times that of Earth. This means that the average density of this world is about 11 g/cm³, which is comparable to the average density of lead. It is one of the densest exoplanets astronomers have found to date.
The extreme density of K2-360 b suggests that it may be the collapsed core of a once larger planet that lost its outer layers due to intense radiation from a nearby host star. Researchers suggest that this could be due to the influence of its neighbor, whose gravity pushed the exoplanet into a closer orbit.
The team’s analysis suggests that K2-360 b probably has a large iron core, accounting for about 48% of its mass. This makes it closer to a super-Earth than a super-Mercury, despite its extreme density. The core is probably surrounded by a rocky mantle, and the surface is covered by an ocean of magma formed by the intense heat this world receives from its star.
According to the researchers, the discovery is important because it provides valuable insights into the architecture of planetary systems and the processes that form them. Exoplanets with ultra-short orbital periods like K2-360 b are relatively rare. The discovery of such a world with a massive external companion will help constrain theories of their formation.
Earlier we told you about exoplanets that could be the target for the first interstellar expedition.
Provided by Phys.org
