(ORDO NEWS) — The mass of TOI-4603b is 13 times that of Jupiter, and the density is almost ten times greater. According to its characteristics, it is located on the very border between giant planets and brown dwarfs.
The star TOI-4603 is located 730 light years from the Sun. In a close orbit near it, a planet was discovered that makes a complete annual revolution in 7.25 days.
Its radius is only four percent larger than that of our Jupiter, but its mass is 12.9 times higher.
Thus, the density of TOI-4603b reaches 14.1 grams per cubic centimeter – almost three times the average density of the Earth and more than that of pure lead (11.3 grams per cubic centimeter).
Scientists used data from the TESS space telescope, which searches for exoplanets by the transit method, by periodically changing the luminosity of stars during the passage of planets in their background.
“This is one of the most massive and densest giant planets known today,” write Akanksha Khandelwal and her co-authors.
As the theory predicts, if a celestial body reaches a mass of about 85 Jupiters, the temperature and pressure in its interior become so high that they trigger thermonuclear reactions of hydrogen.
This is how stars are born. However, the upper mass limit for real planets is 10-13 Jupiters. An intermediate position between them and stars is occupied by brown dwarfs.
They are incapable of thermonuclear fusion with the participation of ordinary hydrogen, but similar reactions with deuterium proceed in them, which are slower and require lower temperatures and pressures.
It is believed that both stars and brown dwarfs form in a similar way – as a result of the collapse of vast clouds of gas and dust.
Planets are formed from the remnants of this substance, which was not included in the main body.
Therefore, although brown dwarfs are found in orbits around stars, as a rule, they are at a sufficient distance, having ended up there due to gravitational capture.
So TOI-4603b, which is so close to its star, and in terms of mass – on the very border between planets and brown dwarfs, seems to be a particularly interesting find.
The same star has at least one more companion, already a full-fledged brown dwarf.
Perhaps it was under his influence that TOI-4603b migrated so close to her. This is also indicated by the elongated, elliptical, shape of its orbit.
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