Professor presents new way to find planets

by MIKE MARTIN, UPI Science Correspondent

PASADENA, Calif. June 7 (UPI) -- Astronomers presented an unusual new way to search for planets in the most difficult of locations -- around bright stars that obscure anything nearby -- at the American Astronomical Society meeting today.

Dan Caton of Appalachian State University in Boone, NC said today his method -- developed with a team of students -- searches for planets around stars that mimic the so-called "Trojan asteroids" found orbiting our own sun in lock step with the planet Jupiter.

Trojan asteroids, Caton explained, are "minor planets" found in Jupiter's orbit that move 60 degrees ahead and behind the planet itself. This system of gravitational stability for a three-body system -- sun, Trojan, and Jupiter -- may also be applied to planets moving with double stars -- the most common star arrangement.

"Since most stars are found in binary pairs, it is important to look for planets in binary systems," Caton told conference attendees.

Though the binary stars Caton is studying are so far away they look like mere dots through a telescope, they periodically dim as one star eclipses the other. A planet in the Trojan position, Caton explained, would cause a smaller eclipse at a predictable time, before or after the stellar eclipses.

Using Appalachian State's own 32 inch (0.8 meter) telescope, Caton and his students take images of several binary systems at times when Trojan planets might come between one of the stars and the telescope, causing a subtle dimming of the star's light.

"You would never get awarded the dozens of nights necessary at a large national observatory to support this work," Caton said. "That's why smaller telescopes continue to play an important role in modern astronomy."

Caton and his team have discovered unusual, repeating "winks" in the V442 Cas system, a star thousands of light-years away. Observations of several other binary systems are under way.

"Not every graduate student gets to work on such a novel project," student Stephen Davis said.