January 28, 2009

Astronomers Observe Planet With Intense Weather Patterns

Astronomers have discovered a planet that goes through phases of intense global warming within a matter of hours.

Researchers used infrared sensors aboard NASA's Spitzer Space Telescope to gauge the temperature of the planet, known as HD8606b.

"We can't get a direct image of the planet, but we can deduce what it would look like if you were there. The ability to go beyond an artist's interpretation and do realistic simulations of what you would actually see is very exciting," said Gregory Laughlin, lead author of the report in the journal Nature.

Researchers observed an extreme change in temperatures from 980 degrees Fahrenheit to 2,240 degrees Fahrenheit.

"This is the first time that we've detected weather changes in real time on a planet outside our solar system," said Laughlin, a professor of astronomy and astrophysics at University of California at Santa Cruz.

He said the discovery would provide astronomers with a new glimpse of atmospheric properties of the planet.

Initially discovered in 2001 by a Swiss team of astronomers, HD8606b is estimated to be about four times the size of Jupiter. The planet orbits a star about 200 light years away from Earth in about 111 days. At its closest approach to the star it experiences radiation about 825 times stronger than when it is most distant.

"If you could float above the clouds of this planet, you'd see its sun growing larger and larger at faster and faster rates, increasing in brightness by almost a factor of 1,000," Laughlin said.

During the 30 hours Spitzer spent observing the planet, researchers got the unexpected chance to witness a secondary eclipse, which also allowed them to get accurate measurements from just the star and thereby determine exact temperatures for the planet.

"Even after finding nearly 200 planets, the diversity and oddness of these new worlds continues to amaze and confound me," said Paul Butler of the Carnegie Institution for Science's Department of Terrestrial Magnetism. Butler made the precision velocity measurements of the host star that allowed the planet's orbit to be calculated.

Jonathan Langton, a postdoctoral researcher at UCSC, worked alongside Laughlin to translate data collected from Spitzer's observations into the planet's response to such extreme conditions.

"The initial response could be described as an explosion on the side facing the star," said Langton, who co-authored the report. "As the atmosphere heats up and expands, it produces very high winds, on the order of 5 kilometers per second, flowing away from the day side toward the night side. The rotation of the planet causes these winds to curl up into large-scale storm systems that gradually die down as the planet cools over the course of its orbit."

On Feb. 14, HD80606b will travel between the Earth and its star. There's a 15 percent chance that amateur astronomers using small telescopes could see it pass by, Laughlin said.


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