Astronomers find 2 large planets, plus possible super-Earth-size one

A team of three University of Florida astronomers contributed to the Kepler spacecraft's discovery of two Saturn-sized planets, plus a possible third planet with a radius just one-and-a-half times that of Earth, orbiting a distant star. NASA announced the discovery, which was also detailed in a paper in this week's edition of Science Express, today.

The Kepler spacecraft, launched to seek Earth-like planets around sun-like stars, has so far identified more than 700 planet candidates that pass in front of or "transit" their stars.

Using traditional methods, extensive follow-up observations would be required to confirm that the candidates are, in fact, planets, according to the Science Express paper. The astronomers who made the discovery used a new method of confirming planets called the transit timing variation method, said Eric Ford, a UF assistant professor of astronomy and the fourth author of the Science Express paper.

"Using transit timing variations, astronomers have a new tool for confirming some planetary systems much more efficiently than before," Ford said. "The discovery also represents the first time that astronomers have discovered more than one planet transiting the same star."

He added, "There are dozens and dozens where one planet transits the star, and there are some other systems where you have multiple planets, but they don't both transit the same star. This system provides new opportunities for testing models of planet formation."

He said the indications of the third planet remain only that, but that if it is confirmed, it would be the planet with the smallest radius yet measured outside our solar system.

However, he said, the possible planet would not be in the "habitable zone," where conditions would allow for liquid water, an essential ingredient for life on Earth. Instead, the planet candidate would be far closer to its star, and very hot as a result. If it is a planet, then its surface temperature likely exceeds 3,000 degrees Fahrenheit, he said.

Source: University of Florida