UF astronomers contribute to NASA’s planet discoveries

Published on University of Florida News on Thursday, January 26, 2012.

GAINESVILLE, Fla. — NASA announced today the discovery of 11 new “solar systems” hosting at least 26 planets found with data from NASA’s Kepler Mission.

Kepler's Planetary Systems, Jan. 2012 Multiple planet systems discovered by NASA's Kepler mission. Newly found planets are shown here in green. The eight planets of the solar system are shown in blue. Credit: NASA Ames/Jason Steffen, Fermilab Center for Particle Astrophysics

The discovery nearly doubles the number of verified Kepler planets so far. It also triples the number of stars known to have more than one planet that transits – or passes in front of — its host star. Such systems are particularly valuable for the clues they provide about how planets form.

Eric B. Ford, associate professor of the astronomy department at the University of Florida, is part of the Kepler Mission science team. Ford’s research group at UF, including graduate student Robert Morehead and postdoctoral associate Althea Moorhead, has contributed to several previous Kepler discoveries. Ford is lead author of the paper describing Kepler-23 and Kepler-24, two of the 11 systems announced today.

In this research, Ford and his team not only describe the two new planetary systems but also develop a new technique that, in Ford’s words “dramatically accelerates planet discovery and will enable astronomers to confirm planets transiting fainter and more distant stars.”

The Kepler Mission uses a 1-meter space telescope to stare constantly at a patch of the Milky Way, registering the small decreases in the light from stars caused when a planet crosses in front of it. With this tool, astronomers are able to constantly monitor more than 160,000 stars at a time.

Until now, confirming that small decreases in a star’s brightness was caused by a planet required additional observations and time-consuming analysis. The new technique takes advantage of the gravitational effects that different planets in a system have on each other’s orbits. By precisely timing the deviations from the expected orbital times caused by this effect, the team was able to detect the gravitational tug exerted by the planets on each other, and confirm 10 of the newly announced planetary systems.

Five of the new planetary systems contain a pair of planets where the inner planet orbits the star twice during each orbit of the outer planet. Another five systems contain a pair of planets where the outer planet circles the star twice for every three times the inner planet orbits its star.

“These configurations help to amplify the gravitational interactions between the planets, similar to how my sons kick their legs on a swing at the right time to go higher,” said Jason Steffen, the Brinson Postdoctoral Fellow at Fermilab Center for Astroparticle Physics and lead author of a paper confirming four of the systems.

The new planets orbit close to their host stars, their size ranging from 1.7 times the radius of Earth to about the size of Jupiter. Fifteen of them are smaller than Neptune and further observations will be required to determine which of them are rocky like Earth and which have thick gaseous atmospheres like Neptune. The confirmed planets orbit their host star once every 6 to 143 days, so all of them are closer to their host star than Venus is to the sun.

The new discoveries will be published in the Astrophysical Journal and the Monthly Notices of the Royal Astronomical Society. Searching for exoplanets using real Kepler data is open to everyone by visiting planethunters.org. For more information about the Kepler mission visit: http://www.nasa.gov/kepler.