Astronomers have used a new technique to confirm a real-life Tatooine, the fictional planet with two suns that was home to Luke Skywalker in "Star Wars."
The planet, Kepler-16b, is about 245 light years from Earth, is a gas giant, and is roughly the size of Saturn. Scientists already knew that the planet existed, but in a recent study, an international team of astronomers explained how they successfully applied a technique that hadn't been previously used to observe a planet orbiting two stars.
"It's a confirmation that our method works," said David Martin, co-author of the study and NASA Sagan Fellow in The Ohio State University's Department of Astronomy. "And it creates an opportunity for us to apply this method now to identify other systems like this."
The technique, called the radial velocity method, has long been used in astronomy. (The first planet ever found around a sun-like star was found using radial velocity - and was found using the same telescope astronomers used to find this one.)
The radial velocity method involves analyzing the spectra of light produced by the stars. Astronomers gather spectra data through telescopes on the ground - in this case, from a telescope based in France, the Observatoire de Haute Provence. That spectra data graphs into a line, but the line "wobbles" as the planet orbits around the two stars, producing a shaky line in the spectra of light. The wobble indicates a planet is there, and astronomers can use it to derive a number of other pieces of information about a planet, including its mass.
Measuring radial velocity is, Martin said, among the best tools astronomers have to identify exoplanets, or planets outside our solar system. But until this study, astronomers had not been able to use it to find planets outside our solar system that orbit two stars.
The study was published this week in the Monthly Notices of the Royal Astronomical Society.
