New massive eccentric brown dwarf discovered

A global crew of astronomers has reported the invention of a brand new brown dwarf, which acquired designation TOI-2490 b. The newfound object is about 74 instances extra huge than Jupiter and orbits a sun-like star on a extremely eccentric orbit. The discovering was detailed in a paper published August 8 on the pre-print server arXiv.

Brown dwarfs (BDs) are intermediate objects between planets and stars, occupying the mass vary between 13 and 80 Jupiter lots (0.012 and 0.076 solar lots). Though many brown dwarfs have been detected to this point, these objects orbiting different stars are a uncommon discover.

Now, a gaggle of astronomers led by Beth A. Henderson of the College of Leicester, UK, has discovered one other transiting brown dwarf. Utilizing TESS, a transit sign was recognized within the mild curve of TOI-2490—a solar-like G-type main sequence star positioned some 872.5 mild years away. The brown dwarf nature of this sign was confirmed by follow-up photometric observations and radial velocity measurements.

“On this paper, we report the invention of TOI-2490b, a brand new, extremely eccentric transiting brown dwarf found utilizing TESS,” the researchers wrote.

In response to the examine, TOI-2490 b is the scale of Jupiter, whereas its mass is about 73.6 Jupiter lots, which yields a density at a stage of 91.6 g/cm³. The brown dwarf orbits the host star each 60.33 days, at a distance of roughly 0.31 AU from it. The equilibrium temperature of TOI-2490 b is estimated to be 464.2 Ok.

The observations discovered that TOI-2490 b has an orbital eccentricity of roughly 0.78. Due to this fact, the astronomers famous that this outcome makes TOI-2490 b essentially the most eccentric brown dwarf within the so-called BD desert—the shortage of brown dwarfs round essential sequence stars inside about 3 AU from the host.

By analyzing the collected information, the authors of the paper concluded that TOI-2490 b seemingly shaped with this excessive stage of eccentricity. They added that this brown dwarf seemingly shaped by way of stellar formation mechanisms and is assumed to have an identical metallicity and age to its guardian star.

The examine additionally discovered that the irradiation temperature of TOI-2490 b modifications by about 1,000 Ok (from 545 to 1,552 Ok) because it travels round its orbit. Nonetheless, additional observations are required to be able to totally perceive such an excessive change.

In terms of the properties of the host star, TOI-2490, it’s as huge because the sun, and its radius is measured to be roughly 1.1 solar radii. The star is estimated to be 7.9 billion years outdated, has a metallicity at a stage of 0.32 dex, and its effective temperature was discovered to be 5,558 Ok.

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