Astrophysicists Identify Pair of Brown Dwarfs Engaged in Celestial Ballet
Astrophysicists have made an exciting discovery of twin brown dwarfs engaged in a cosmic dance.
TroibNews 
In 1995, astronomers made a groundbreaking confirmation of a brown dwarf, a celestial object that sits between the classifications of stars and planets. However, new research reveals that this initial finding was only part of the story.
Recent studies have reexamined the brown dwarf originally known as Gliese 229B and discovered it consists of two brown dwarfs that orbit each other at an incredibly close distance while also revolving around a nearby small star. These findings have emerged from investigations using telescopes based in Chile and Hawaii.
The two brown dwarfs are gravitationally bound in what scientists refer to as a binary system—an arrangement frequently seen among stars. The brown dwarf previously identified as Gliese 229B is now designated Gliese 229Ba, possessing a mass 38 times that of Jupiter, our solar system's largest planet. Its companion, Gliese 229Bb, is slightly lighter, with a mass 34 times that of Jupiter.
Located 19 light-years away in the constellation Lepus, this binary system is relatively close by astronomical standards. A light-year, which measures the distance light travels in a year, equals approximately 5.9 trillion miles.
Instances of binary brown dwarfs are uncommon. The two in question orbit each other every 12 days, maintaining a distance just 16 times that between Earth and the moon. Only one other known pair of brown dwarfs holds a similarly close orbit.
Brown dwarfs themselves occupy a unique niche between stars and planets. They represent what could be termed "wannabe stars," as they do not possess the necessary mass to ignite nuclear fusion in their cores during their formation. Nevertheless, their mass exceeds that of the largest known planets.
"A brown dwarf is an object that fills the gap between a planet and a star. They are formally defined as objects that can burn a heavy form of hydrogen called deuterium, but not the most common basic form of hydrogen," noted Sam Whitebook, a graduate student at Caltech’s division of physics, mathematics, and astronomy, and the lead author of one of the studies shared in the Astrophysical Journal Letters.
"In practice, this means they range in mass from approximately 13 to 81 times the mass of Jupiter. Because they can't fuse hydrogen, they can't ignite the fusion channels that power most stars. This causes them to just glow dimly as they cool down," Whitebook explained.
The year 1995 was pivotal for astronomers, as it also saw the announcement of the first exoplanet beyond our solar system. Until the identification of Gliese 229B, the existence of brown dwarfs had merely been a hypothesis. However, anomalies surrounding Gliese 229B, particularly its measured mass of about 71 times that of Jupiter, raised questions.
"This didn't make any sense since an object of that mass would be much brighter than Gliese 229B," commented Jerry Xuan, a Caltech astronomer and lead author of another study published in the journal Nature. "In fact, some models predict that objects with masses above 70 Jupiter masses fuse hydrogen and become stars, which was clearly not happening here."
The latest observations successfully identified the two distinct brown dwarfs. They orbit a common red dwarf star, which has a mass roughly 60% that of our sun. Although both brown dwarfs have greater mass than Jupiter, their diameters are smaller due to their higher density.
"We still don't really know how different brown dwarfs form, and what the transition between a giant planet and a brown dwarf is. The boundary is fuzzy," Xuan expressed. "This finding also shows us that brown dwarfs can come in configurations we were not expecting. This goes to show how complex and messy the star formation process is. We should always be open to surprises."
Frederick R Cook for TROIB News
Recent studies have reexamined the brown dwarf originally known as Gliese 229B and discovered it consists of two brown dwarfs that orbit each other at an incredibly close distance while also revolving around a nearby small star. These findings have emerged from investigations using telescopes based in Chile and Hawaii.
The two brown dwarfs are gravitationally bound in what scientists refer to as a binary system—an arrangement frequently seen among stars. The brown dwarf previously identified as Gliese 229B is now designated Gliese 229Ba, possessing a mass 38 times that of Jupiter, our solar system's largest planet. Its companion, Gliese 229Bb, is slightly lighter, with a mass 34 times that of Jupiter.
Located 19 light-years away in the constellation Lepus, this binary system is relatively close by astronomical standards. A light-year, which measures the distance light travels in a year, equals approximately 5.9 trillion miles.
Instances of binary brown dwarfs are uncommon. The two in question orbit each other every 12 days, maintaining a distance just 16 times that between Earth and the moon. Only one other known pair of brown dwarfs holds a similarly close orbit.
Brown dwarfs themselves occupy a unique niche between stars and planets. They represent what could be termed "wannabe stars," as they do not possess the necessary mass to ignite nuclear fusion in their cores during their formation. Nevertheless, their mass exceeds that of the largest known planets.
"A brown dwarf is an object that fills the gap between a planet and a star. They are formally defined as objects that can burn a heavy form of hydrogen called deuterium, but not the most common basic form of hydrogen," noted Sam Whitebook, a graduate student at Caltech’s division of physics, mathematics, and astronomy, and the lead author of one of the studies shared in the Astrophysical Journal Letters.
"In practice, this means they range in mass from approximately 13 to 81 times the mass of Jupiter. Because they can't fuse hydrogen, they can't ignite the fusion channels that power most stars. This causes them to just glow dimly as they cool down," Whitebook explained.
The year 1995 was pivotal for astronomers, as it also saw the announcement of the first exoplanet beyond our solar system. Until the identification of Gliese 229B, the existence of brown dwarfs had merely been a hypothesis. However, anomalies surrounding Gliese 229B, particularly its measured mass of about 71 times that of Jupiter, raised questions.
"This didn't make any sense since an object of that mass would be much brighter than Gliese 229B," commented Jerry Xuan, a Caltech astronomer and lead author of another study published in the journal Nature. "In fact, some models predict that objects with masses above 70 Jupiter masses fuse hydrogen and become stars, which was clearly not happening here."
The latest observations successfully identified the two distinct brown dwarfs. They orbit a common red dwarf star, which has a mass roughly 60% that of our sun. Although both brown dwarfs have greater mass than Jupiter, their diameters are smaller due to their higher density.
"We still don't really know how different brown dwarfs form, and what the transition between a giant planet and a brown dwarf is. The boundary is fuzzy," Xuan expressed. "This finding also shows us that brown dwarfs can come in configurations we were not expecting. This goes to show how complex and messy the star formation process is. We should always be open to surprises."
Frederick R Cook for TROIB News
