Astronomers Use Ultra-sensitive Camera To Measure Size Of Planet Orbiting Star

When the planet WASP-10b crosses the disk of its star, WASP-10, the brightness of the star decreases, allowing scientists to measure the precise size of the planet. (Credit: Institute for Astronomy, University of Hawaii at Manoa)

From Science Daily:

ScienceDaily (Dec. 17, 2008) — A team of astronomers led by John Johnson of the University of Hawaii's Institute for Astronomy has used a new technique to measure the precise size of a planet around a distant star. They used a camera so sensitive that it could detect the passage of a moth in front of a lit window from a distance of 1,000 miles.

The camera, mounted on the UH 2.2-meter telescope on Mauna Kea, measures the small decrease in brightness that occurs when a planet passes in front of its star along the line-of-sight from Earth. These "planet transits" allow researchers to measure the diameters of worlds outside our solar system.

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