Kepler’s follow-up observers confirm new discoveries
More than 2,300 exoplanet candidate discoveries have made it the most prolific planet hunter in history. But even NASA’s Kepler mission needs a little help from its friends.
Enter the Kepler follow-up observation program, a consortium of astronomers dedicated to getting in-depth with the mission’s findings and verifying them to an extremely high degree of confidence.
A single Kepler observation alone is often not enough to prove that the telescope has found an exoplanet, said Nick Gautier, the mission’s deputy project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., who coordinated and continues to help run Kepler’s robust follow-up program.
Kepler finds exoplanets by watching for worlds that move directly between the telescope and their host stars. As they do this, they block a tiny fraction of the star’s light, an event astronomers call a “transit.”
For nearly a decade, Cal-Berkeley astronomer Geoff Marcy and his colleagues have been using the W. M. Keck telescopes to discover giant planets orbiting distant stars. Now, with the successful launch of NASA’s Kepler mission, they will be using Keck I’s ten-meter astronomical eye to discover distant Earths. Kepler will pick out Earth-like candidates. Keck will then zero in on them and determine, with certainty, if they are at all similar to our home planet.
“Keck and NASA have a long-standing partnership to push astronomy research to its fullest potential. This Keck-Kepler collaboration gives that partnership a compelling new scientific focus,” said Taft Armandroff, the Director of Keck Observatory headquartered in Kamuela, HI.
Kepler was launched from NASA’s Kennedy Space Center last Friday. Aboard the spacecraft is an 84-megapixel camera that will focus on a single region of the sky and snap repeated images of 100,000 stars looking for those that dim periodically. By studying the stars’ episodic decreases in starlight, astronomers will be able to determine the diameter of the object that passes in front of the star, blocks its light and causes the dimming.
“Kepler does not tell astronomers with certainty if the object taking a bite out of the starlight is a planet or another star. That is where Keck plays a crucial role to the Kepler mission,” said Marcy, a frequent Keck user and Kepler mission co-investigator. He, along with a large international planet-hunting team, has discovered nearly half of the 300-plus known planets outside the Solar System.