STSci: Companion to Brown Dwarf Challenges Simple Definition

[bystander]

Small Companion to Brown Dwarf Challenges Simple Definition
HubbleSite.org: STScI-2010-03 - 2010 Apr 06

As our telescopes grow more powerful, astronomers are uncovering objects that defy conventional wisdom. The latest example is the discovery of a planet-like object circling a brown dwarf. It's the right size for a planet, estimated to be 5-10 times the mass of Jupiter. But the object formed in less than 1 million years — the approximate age of the brown dwarf — and much faster than the predicted time it takes to build planets according to some theories.

A Planet-like Companion Growing up in the Fast Lane
Gemini Observatory - 2010 Apr 06

The cliché that youth grow up so fast is about to take on a new twist. This is due to the discovery of a very young planet-like object (with a mass somewhere between 5-10 times that of Jupiter), paired with a low-mass brown dwarf. What is unique about this system is that the planet-like body appears to have formed in about a million years–more rapidly than some theories of planet formation predict.
...
While different processes or combinations may be relevant for each system, here are three possible scenarios for the formation of planetary-mass companions: 1) Dust in a circumstellar disk slowly agglomerates to form a rocky planet 10 times larger than the Earth, which then accumulates a large gaseous envelope; 2) the disk is unstable causing a clump of gas to quickly collapse and form an object the size of a gas-giant planet; or, 3) rather than forming in a disk, a companion forms from the collapse of the vast cloud of gas and dust in the same manner and at the same time as the primary body.

If the last scenario does occur, then this discovery demonstrates that nature can make planetary-mass bodies through the same mechanism that builds stars. This is the likely solution because the planet-like companion is too young to have formed by the first scenario, which is very slow. The second mechanism occurs rapidly, but any disk around this low-mass brown dwarf probably did not contain enough material to make an object with a mass of 5-10 Jupiter masses.
...
Additional evidence to indicate that the new planetary-mass companion formed like a binary star comes from the presence of a nearby small red star that is gravitationally connected to the pair. When the Gemini observations were made, the adaptive optics system used the distant red star as a reference guide star (see background below). In the process, Gemini discovered yet another brown dwarf very close to the distant red star, making 2M044144 a possible member of a quadruple system. Luhman believes that all four objects may have formed in the same cloud collapse: “The configuration closely resembles quadruple star systems, suggesting that all of its components formed like stars,” Luhman said.

[orin stepanek]

http://hubblesite.org/newscenter/archiv ... 03/image/a

[Chris Peterson]

I believe "melanin enhanced little person" is the acceptable term, these days.

[orin stepanek]

http://hubblesite.org/newscenter/archiv ... 03/image/a

I must be having delusions; I thought I posted this yesterday. Anyway hubble found an interesting sight. Is it a planet or a Dwarf?

[dougettinger]

Small Companion to Brown Dwarf Challenges Simple Definition
HubbleSite.org: STScI-2010-03 - 2010 Apr 06

As our telescopes grow more powerful, astronomers are uncovering objects that defy conventional wisdom. The latest example is the discovery of a planet-like object circling a brown dwarf. It's the right size for a planet, estimated to be 5-10 times the mass of Jupiter. But the object formed in less than 1 million years — the approximate age of the brown dwarf — and much faster than the predicted time it takes to build planets according to some theories.

A Planet-like Companion Growing up in the Fast Lane
Gemini Observatory - 2010 Apr 06

The cliché that youth grow up so fast is about to take on a new twist. This is due to the discovery of a very young planet-like object (with a mass somewhere between 5-10 times that of Jupiter), paired with a low-mass brown dwarf. What is unique about this system is that the planet-like body appears to have formed in about a million years–more rapidly than some theories of planet formation predict.
...
While different processes or combinations may be relevant for each system, here are three possible scenarios for the formation of planetary-mass companions: 1) Dust in a circumstellar disk slowly agglomerates to form a rocky planet 10 times larger than the Earth, which then accumulates a large gaseous envelope; 2) the disk is unstable causing a clump of gas to quickly collapse and form an object the size of a gas-giant planet; or, 3) rather than forming in a disk, a companion forms from the collapse of the vast cloud of gas and dust in the same manner and at the same time as the primary body.

If the last scenario does occur, then this discovery demonstrates that nature can make planetary-mass bodies through the same mechanism that builds stars. This is the likely solution because the planet-like companion is too young to have formed by the first scenario, which is very slow. The second mechanism occurs rapidly, but any disk around this low-mass brown dwarf probably did not contain enough material to make an object with a mass of 5-10 Jupiter masses.
...
Additional evidence to indicate that the new planetary-mass companion formed like a binary star comes from the presence of a nearby small red star that is gravitationally connected to the pair. When the Gemini observations were made, the adaptive optics system used the distant red star as a reference guide star (see background below). In the process, Gemini discovered yet another brown dwarf very close to the distant red star, making 2M044144 a possible member of a quadruple system. Luhman believes that all four objects may have formed in the same cloud collapse: “The configuration closely resembles quadruple star systems, suggesting that all of its components formed like stars,” Luhman said.

If a planet is orbiting a brown dwarf only 1 million years old, then the nebular theory is on its way to being disproven or major remodeling is needed. How do astronomers know the age of this star ? What isotope is being analyzed?

Doug Ettinger
Pittsburgh, PA

[dougettinger]

I believe "melanin enhanced little person" is the acceptable term, these days.

Even though this person is enhanced, this term is still politically incorrect.

DBE

[Chris Peterson]

Even though this person is enhanced, this term is still politically incorrect.

What isn't, anymore? (BTW, the reference wasn't to a person.)