Monday, November 26, 2012

Planets Without Suns

There are a number of starless planets roaming about in space, but one in particular is creating a lot of excitement among astronomers. It is only 100 light years away from Earth, which in astronomical distances is practically a hop, skip and a jump away, and it is very young.

The planet, a gas giant, has no name, at least as yet. It is known by its catalog number, CFBDSIR2149-0403. The reason astronomers are so excited is that they have a chance for a close-up study of an object without interference from starlight. Astronomers theorize that there may be billions of these objects wandering around in our galaxy.

CFBDSIR2149-0403 was detected in 2009 by astronomers in Hawaii using heat signals and an infrared camera. A second team at the Paranal Observatory in Chile then aimed a large telescope at the object and found the object. They describe it as being nearly identical in circumference to Jupiter, although it appears to be from four to seven times larger in mass. They analyzed its atmosphere and found ammonia, methane and water vapor. These same gases are found in our own solar system’s gas giants, Saturn, Jupiter, Neptune and Uranus.

The “substellar object” was found near the southern constellation Dorado, but may actually not be part of the AB Doradus group, which is a collection of 30 stars that formed from the same cloud of galactic gas. Astronomers have also found that it is a very young “planet,” aged somewhere between about 50 and 120 million years old.

Objects like CFBDSIR2149-0403, wandering without a star to illuminate them, are very hard to spot. Some of the younger objects, however, still carry a residual glow caused by their own heat.

Some of these stars may eventually be captured by a sun if they happen to wander close enough to be pulled in by the star’s gravity field. Others may wander for an eternity. One pair, however, found one another, circling around each other rather than around a sun.

 Since our solar system’s giant gas planets share gases in common with CFBDSIR2149-0403, one has to wonder whether they were once roaming stars that happened to wander into the Sun’s gravitational influence and become part of our own system. Perhaps there’s hope yet that CFBDSIR2149-0403 will yet find a home.

There’s more information on this orphan planet here

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