Aztecs discover multi-planet system

by Ana Ceballos

Courtesy NASA-JPL-Caltech-T.Pyle

After collecting two years worth of data, a team led by San Diego State astronomy Professor Jerome Orosz, Ph.D., discovered the first transiting circumbinary multi-planet system.

The system, called Kepler-47, was identified when Orosz denoted a pattern of slight dips of brightness crossing through the path of the host stars. The Kepler space telescope, which has 95 million pixels and is extremely sensitive, was a key tool for the discovery of the system 5,000 light-years away, according to Orosz.

The team included undergraduate and graduate students, who helped identify and analyze the dips, as well as astronomy professor William Welsh, who presented the new find to the International Astronomical Union meeting in Beijing.

In addition to identifying the stability of the system, it was also determined if the planets were to be left alone, they would persist and sustain themselves, according to Orosz.

The first planet, Kepler-47b, is three times larger than the diameterof Earth, orbits a pair of stars every 49 days and has a white appearance. The second planet, Kepler- 47c, completes its orbit in 303 days, is slightly bigger than Uranus and has a blue appearance. The smaller star undergoes its rotation around the larger star in about one week.

“The first of the two planets is located in the habitable zone, just like Earth,” Orosz said. “This planet is most likely made of gas and hastemperatures at the freezing point of water.”

Because of the nature of the Kepler system and the proximity of thesmaller star orbiting the larger sun, Kepler-47b would have very unstable climate.

When mentioning the new discovery to two SDSU astronomy undergraduates, Anthony Sanchez and Thomas Maher, they associated the twin stars of the Kepler system to Luke Skywalker’s fictional home world, Tatooine, in the original “Star Wars” film.

Sanchez, a big “Star Wars” fan, was fascinated by the resemblance of the twin stars’ and the idea that one of these planets may be habitable.

“It is overwhelming to think that our universe is as immense,” Maher said. “I have stopped wondering about whether or not there is alien life out there. How can such a big universe with diverse solar systems not be home to alien life? It is silly to think we are the only ones.”

Orosz hopes to discover more planets in the Kepler system and is excited to analyze the data he will receive every three months.

“Life is abundant and the space among stars is vast,” Orosz said. “Our goal right now is to find more systems like Kepler-47 and possibly find more habitable planets.”