Friday, November 14, 2008

First Photographed Exoplanets

the OWH reports that two separate teams of astronomers have directly imaged 4 exoplanets in two different star systems. A team led by Bruce MacIntosh of Livermore National Labs used two ground based telescopes and the other team used Hubble imagery. The system studied by the MacIntosh team managed to image three distinct planets in a single system, while the Hubble imagery was able to compare photos taken in 2006 with another taken from 2004 to show that planet's orbit lies within the system's dust ring, making it quite unlikely to be a brown dwarf, an alternative explanation that some of their more skeptical fellow researchers have proposed for these bodies. All four planets are Jupiter type gas giant planets.

"The planet discovered by Hubble is one of the smallest exoplanets found yet. It's somewhere between the size of Neptune and three times bigger than Jupiter. And it may have a Saturn-like ring.

It circles the star Fomalhaut, pronounced FUM-al-HUT, which is Arabic for "mouth of the fish." It's in the constellation Piscis Austrinus and is relatively close by - a mere 148 trillion miles away, practically a next-door neighbor by galactic standards. The planet's temperature is around 260 degrees, but that's cool by comparison to other exoplanets.

The planet is only about 200 million years old, a baby compared to the more than 4 billion-year-old planets in our solar system. That's important to astronomers because they can study what Earth and planets in our solar system may have been like in their infancy, said Paul Kalas at the University of California, Berkeley. Kalas led the team using Hubble to discover Fomalhaut's planet."

The MacIntosh team discovered its first planet in 2007 and follow up study showed the two additional planets. All three planets are several Jupiter masses and ths system astronomical name is HR8799, It is visible form Earth with binoculoars, lies in the constellation Pegasus and is 767 trillion miles from our solar system.

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