This Ancient Star Has Five Earth-size Planets:Astronomers have discovered a star that’s 11.2 billion

This Ancient Star Has Five Earth-size Planets:Astronomers have discovered a star that’s 11.2 billion years old and has at least five Earth-size planets.They found it while poring over four years of data from NASA’s Kepler spacecraft.They say the discovery shows that planets the size of Earth have formed throughout the universe’s history, which means there’s a chance very ancient life exists in the galaxy.The research published in the Astrophysical Journal describes Kepler-444, a star that’s 25 percent smaller than our sun and is 117 light years from Earth. The star’s five known planets have sizes that fall between Mercury and Venus.Those planets are so close to their star that they complete their orbits in fewer than 10 days. At that distance, they’re all much hotter than Mercury and aren’t habitable.Steve Kawaler, an Iowa State University professor of physics and astronomy and a coauthor of the study, says Kepler-444 is very bright and can be easily seen with binoculars.Kawaler’s role within the research team was to help with the stellar seismology work that determined the size of Kepler-444. To do that, Kawaler and the rest of the team studied sound waves within the star. Those sound waves affect the star’s temperature, creating pulsating changes in brightness that offer clues to the star’s diameter, mass and age.Kepler takes high-precision measurements of those changes in brightness. That’s how Kepler does its primary job: finding distant planets by measuring tiny changes in brightness as they pass in front of their stars.“This is one of the oldest systems in the galaxy,” Kawaler says of the Kepler discovery, noting that our sun is 4.5 billion years old. “Kepler-444 came from the first generation of stars. This system tells us that planets were forming around stars nearly 7 billion years before our own solar system.“Planetary systems around stars have been a common feature of our galaxy for a long, long time.”Tiago Campante, a research fellow at the University of Birmingham, is leader of the research project and first author of the paper. -- source link

More pics about