Hazy red sunset discovered on extra-solar planet

December 11th, 2007 - 7:14 pm ICT by admin  

Washington, Dec.11 (ANI): A team of astronomers have used the NASA/ESA Hubble Space Telescope to detect, for the first time, strong evidence of hazes in the atmosphere of a planet orbiting a distant star.
The discovery comes after extensive observations made recently with Hubbles Advanced Camera for Surveys (ACS).
The team, led by Frederic Pont from the Geneva University Observatory in Switzerland, used Hubbles ACS to make the first detection of hazes in the atmosphere of the giant planet.
“One of the long-term goals of studying extra-solar planets is to measure the atmosphere of an Earth-like planet, this present result is a step in this direction” says Pont.
The new observations were made as the extra-solar planet, dubbed HD 189733b, passed in front of its parent star in a transit.
The planet itself, orbiting close to its parent star, is a hot-Jupiter type of gas giant slightly larger than Jupiter. The proximity to its star results in an atmospheric temperature of roughly seven hundred degrees Celsius.
Measurements of the way light varies as the planet passes in front of its parent star indicates that HD 189733b has neither Earth-sized moons nor any discernable Saturn-like ring system.
Hubbles ACS camera, coupled with a grism (a kind of cross between a prism and a diffraction grating) allowed the astronomers to make extremely accurate measurements of the spectrum of HD 189733b, allowing conclusions to be drawn about the composition of the planets atmosphere. Where the scientists had expected to see the fingerprints of sodium, potassium and water there were none.
This finding, combined with the distinct shape of the planets spectrum, infers that high level hazes (with an altitude range of roughly 1000 km) are present.
According to the scientists the haze probably consists of tiny particles (less than 1/1000 mm in size) of condensates of iron, silicates and aluminium oxide dust (the compound on Earth which the mineral sapphire is made of).
As part of the observations of HD 189733, the teams of astronomers also needed to accurately account for the variations in the stars brightness during the set of observations.
Starspots like those seen on our own Sun may cover several percent of the star and are thought to be about 1000 degrees Celsius cooler than the rest of HD 189733s surface. It was found that there is a starspot on the stars surface that is over 80,000 km across. (ANI)

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