An international team of astronomers reported the discovery of a new brown dwarf, designated TOI-2490 b. It orbits a sun-like star at a record eccentricity.
Brown dwarfs are objects that occupy an intermediate position between gas giants and stars. Their masses range from 13 to 80 Jupiter masses. In the interior of brown dwarfs, reactions involving deuterium and lithium nuclei can take place, but their mass is not sufficient to support constant thermonuclear reactions involving hydrogen. This is why brown dwarfs are sometimes called failed stars.
TOI-2490 b was discovered while analyzing data collected by the TESS space telescope. It orbits a sun-like star located 872.5 light-years from Earth. The luminary is 10% larger than the Sun and older than it. As for the brown dwarf, it is comparable in size to Jupiter, but its mass is 73.6 times greater than Jupiter’s. Thus, it lacked quite a bit to turn into a star.
This brown dwarf has interested astronomers with its orbit. It has an eccentricity of 0.78. It is so elongated that TOI-2490 b is constantly experiencing powerful temperature fluctuations. As the brown dwarf approaches the star during its 60-day orbit, its temperature rises by about 1,000 degrees Celsius compared to when it passes the apocenter of its orbit.
According to the researchers, TOI-2490 b has one of the most elongated orbits among all known brown dwarfs orbiting stars. It most likely originally formed in an orbit with such a high level of eccentricity.
Earlier we told you about how astronomers found a record fast brown dwarf that could have come from another galaxy.
According to Phys.org
