University of Warwick/Mark Garlick
A group of astronomers has discovered a giant planet orbiting a tiny red dwarf star.
The planet, dubbed TOI-6894b, orbits a tiny red dwarf at a distance of 241 light-years from Earth. According to an astrophysicist from the Space Science Laboratory Mallard in London Vincent Van Eylen, it is still unclear how such a large planet could have formed next to such a tiny star.
For a long time, astronomers have been convinced that massive planets cannot form around stars with less than a third of the solar mass. However, several such systems have been discovered that challenge this belief.
British astronomer Edward Bryant of of University College London and colleagues used NASA’s TESS orbiting telescope and discovered 15 potential giant planets, including TOI-6894b, orbiting tiny, low-mass stars. The astronomers focused on observing TOI-6894b and its parent star.
Astronomers have found that planet mass is about 17% of the mass of Jupiter, or about 53 times the mass of the Earth. The planet’s radius is slightly larger than that of Saturn, and it orbits its parent star, with a mass of about 20% of the sun’s, in just 3 days.
«We did not expect planets like TOI-6894b to form around stars with such low masses. This discovery will be a cornerstone for understanding the extremes of giant planet formation», — notes Edward Bryant.
These planets are as TOI-6894b orbiting low-mass stars violate the established model core accretion, which is the most common theory of planet formation. Typically, the core of a giant planet grows until it is massive enough to suck in gas from the protoplanetary disk. However, astronomers did not expect protoplanetary disks around low-mass stars to have enough material to form giant planets.
Astronomers believe that TOI-6894b could have been slowly accumulating gas over time, or this planet was formed from a gravitationally unstable protoplanetary disk that collapsed into a planet. According to the scientists, studying the distribution of material in the planet’s atmosphere can provide some clues about how it was formed. Researchers will use the «James Webb» space telescope to observe the planet’s atmosphere over the next year.
The results of the study are published in the journal Nature
Source: LiveScience