New Castle News

January 18, 2014

Westminster College professor discovers planet

By Staff
New Castle News

NEW CASTLE — A Westminster College professor and two students have discovered a new planet.

The Saturn-mass exoplanet — a planet that orbits other stars — was co-discovered by Dr. Thomas Oberst,  assistant professor of physics, and undergraduate students Ryan Avril and Samuel Mellon. The planet, named KELT-6b, orbits a star more than 700 light-years away in the constellation Coma Berenices.

It is the first planet that Westminster College has helped discover.

An article detailing the discovery was published Saturday in the February issue of the Astronomical Journal. The lead author of the article is Karen Collins of the University of Louisville. Oberst, Avril, and Mellon are coauthors. The authors first announced the planet at the 222nd meeting of the American Astronomical Society.

“We feel privileged to have had the opportunity to be part of this discovery, which required the work of more than 40 members of the KELT-North team,” Oberst said. “Discovering strange new worlds like this helps put our own solar system and planet in context.”

KELT-6b was found to have a mass near that of Saturn, but orbits its host star more than 100 times closer than Saturn. Thus, the star’s heat has caused KELT-6b to swell to a diameter 50 percent larger than Saturn, and has likely vaporized any rings the planet may have had. “There is no chance of life on this planet,” Oberst added.

Because exoplanets are difficult to photograph directly, Oberst, Avril, and Mellon detected KELT-6b using the transit technique, whereby the planet’s host star was observed to dim as the planet passed in front of the star during its orbit. Although several hundred transiting exoplanets have been confirmed, KELT-6b has one of the 20 brightest host stars, making it especially conducive to follow-up studies. The host star is also especially deficient in metals, providing a test-case for how metals influence planet formation and evolution.

The planet’s transit was first spotted by the Kilodegree Extremely Little Telescope (KELT) North, a robotic telescope in Arizona operated by astronomers at the Ohio State University and Lehigh University. Oberst, Avril, and Mellon then observed the transit more precisely using a larger telescope at the Westminster College Observatory, helping to confirm that it was indeed due to a planet, rather than a binary star or other type of false-positive.