In a new study, scientists found important information about the origins of brown dwarfs.
Their finding showed that brown stars could form along with the star from a gas and dust disk, just as planets do.
The study was conducted by Astronomers from Centre for Astronomy of Heidelberg University.
A brown dwarf is a type of substellar object that occupies the mass range between the heaviest gas giant planets and the lightest stars.
It can have a mass between approximately 13 to 75–80 times that of Jupiter.
Previous research has shown that brown dwarfs could fill the “gap” between stars and the much smaller planets. These are two very different types of astronomical objects.
On one hand, brown stars can be big enough to generate energy in their core through nuclear fusion.
On the other hand, they are not sufficiently massive to ignite hydrogen in their cores and create their own light.
To find out how brown dwarfs originate, the team in the study examined the star ν Ophiuchi in the Milky Way, which is orbited by two brown dwarfs.
The astronomers were able to locate the brown dwarfs based on the heat they continue to radiate after formation.
In the study, they analyzed the variations in the radial velocity of the star ν Ophiuchi using telescopes in the USA and Japan.
The researchers found that the star has a mass slightly greater than two and a half times that of the Sun.
It is located about 150 light years from Earth in the constellation Ophiuchus.
Further analysis showed that ν Ophiuchi is being orbited by two brown dwarfs.
The two brown dwarfs have an orbital period of about 530 and 3,185 days.
This means the brown dwarf closest to ν Ophiuchi orbits its star exactly six times while the more distant brown dwarf completes only one orbit.
The team suggests that the new findings provide very important information on the evolution of brown dwarfs.
The 6:1 resonance is a strong indication for the hypothesis that brown dwarfs could form in the so-called protoplanetary disk of gas and dust which surrounds the parent star.
The study provides the first sure sign that brown dwarfs can form in a protoplanetary disk.
The team hopes that other such findings that may help them to clarify how many of the “failed” stars are actually more massive siblings of Jupiter and Saturn.
The leader of the study is Prof. Dr. Andreas Quirrenbach.
The study is published in Astronomy & Astrophysics.
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