Side Jobs 
The Kepler spacecraft has one mission: to find planets in other star systems. And it’s doing that job quite well. So far, astronomers have found evidence of almost 3,000 possible planets in its observations.
Kepler stares at 150,000 stars almost non-stop, looking for a star to fade a bit as a planet passes in front of it, blocking a tiny bit of its light. But those same observations can also tell astronomers a lot about the stars themselves, as well as many other objects in the space telescope’s field of view.
Astronomers have used the observations, for example, to watch changes in quasars - brilliant disks of hot gas around supermassive black holes at the hearts of distant galaxies.
The Kepler data are also helping sort different kinds of variable stars - stars that change brightness over periods of days, weeks, or months.
One study, for example, has followed more than 300 stars for more than three years, using observations from Kepler and from several telescopes on the ground. The survey shows that almost a hundred of the target stars pulse in and out like beating hearts. More than 50 stars have surfaces that are mottled by dark starspots or that are otherwise altered by their magnetic fields. And a couple of dozen were found to have close companions.
Kepler has also revealed a class of binary stars where the two companions change shape as the distance between them changes. We’ll have more about that tomorrow.
Script by Damond Benningfield, Copyright 2013