Nivekella
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Failed Star Spawning Mini Solar System
By Irene Mona Klotz, Discovery News
Dec. 5, 2005?The faint Chameleon constellation near the south celestial pole is aptly named.
Astronomers have discovered the beginnings of a solar system around an object too small to become a true star.
Instead, the telltale bulge of planetary pregnancy sits around a rather ordinary and relatively small body called a brown dwarf.
Just eight times the mass of Jupiter, the object, which has been designated Cha 110913-773444, is even smaller than some of the planets astronomers have found circling other stars.
Yet a team led by Kevin Luhman at Pennsylvania State University believe the disk around the brown dwarf has enough mass in tow to make a small gas giant planet and a few Earth-sized rocky worlds.
If the disk eventually consolidates into planets, the system, with its brown dwarf central body and planetary offspring would be about 1 percent the size of our solar system.
"Our goal is to determine the smallest 'sun' with evidence for planet formation," said Luhman, who also led in the discovery last year of a brown dwarf 15 times larger than Jupiter that has a protoplanetary disk.
Scientists are in a quandary about what the new system would be called.
"There are two camps when it comes to defining planets versus brown dwarfs," said Giovanni Fazio with the Harvard-Smithsonian Center for Astrophysics and a member of Luhman's team.
"Some go by size and others go by how the object formed. For instance, this new object would be called a planet based on its size, but a brown dwarf based on how it formed."
Added Luhman, "The question then becomes, what do we call any little bodies that might be born from this disk: planets or moons?"
Brown dwarfs, like stars, condense from clouds of gas and dust. However, they do not have enough mass to maintain nuclear fusion in their cores, like stars.
The new object, which was discovered with a combination of ground- and space-based telescopes, is estimated to be about 2 million years old, quite young in astronomical timeframes. Our sun is about 4.6 billion years old.
Luhman estimates it will take another 5 million to 10 million years for the brown dwarf's protoplanetary disk to bear fruit.
Typically scientists look for older objects to learn about how a system evolves, but there are very few brown dwarfs as small as the one in Chameleon.
"There's really only a handful at that size," he said.
The team's findings are to be published in next week's issue of The Astrophysical Journal Letters.
By Irene Mona Klotz, Discovery News
Dec. 5, 2005?The faint Chameleon constellation near the south celestial pole is aptly named.
Astronomers have discovered the beginnings of a solar system around an object too small to become a true star.
Instead, the telltale bulge of planetary pregnancy sits around a rather ordinary and relatively small body called a brown dwarf.
Just eight times the mass of Jupiter, the object, which has been designated Cha 110913-773444, is even smaller than some of the planets astronomers have found circling other stars.
Yet a team led by Kevin Luhman at Pennsylvania State University believe the disk around the brown dwarf has enough mass in tow to make a small gas giant planet and a few Earth-sized rocky worlds.
If the disk eventually consolidates into planets, the system, with its brown dwarf central body and planetary offspring would be about 1 percent the size of our solar system.
"Our goal is to determine the smallest 'sun' with evidence for planet formation," said Luhman, who also led in the discovery last year of a brown dwarf 15 times larger than Jupiter that has a protoplanetary disk.
Scientists are in a quandary about what the new system would be called.
"There are two camps when it comes to defining planets versus brown dwarfs," said Giovanni Fazio with the Harvard-Smithsonian Center for Astrophysics and a member of Luhman's team.
"Some go by size and others go by how the object formed. For instance, this new object would be called a planet based on its size, but a brown dwarf based on how it formed."
Added Luhman, "The question then becomes, what do we call any little bodies that might be born from this disk: planets or moons?"
Brown dwarfs, like stars, condense from clouds of gas and dust. However, they do not have enough mass to maintain nuclear fusion in their cores, like stars.
The new object, which was discovered with a combination of ground- and space-based telescopes, is estimated to be about 2 million years old, quite young in astronomical timeframes. Our sun is about 4.6 billion years old.
Luhman estimates it will take another 5 million to 10 million years for the brown dwarf's protoplanetary disk to bear fruit.
Typically scientists look for older objects to learn about how a system evolves, but there are very few brown dwarfs as small as the one in Chameleon.
"There's really only a handful at that size," he said.
The team's findings are to be published in next week's issue of The Astrophysical Journal Letters.
