Instrument That Studies Binary Stars May Soon Image Exoplanets

A new instrument that combines two high-resolution telescope techniques -- adaptive optics and interferometry -- has for the first time distinguished and studied the individual stars in a nearby binary star system, demonstrating promise for eventually picking out planets around other stars.

In the December issue of the journal Astronomy & Astrophysics, University of California, Berkeley, astronomers and an international team of colleagues report that they were able to resolve in visible light the two stars in the binary star system Capella, which orbit one another at about the distance of Venus from the Sun and until now have been indistinguishable from Earth. Capella is 43 light-years from Earth and the brightest star in the constellation Auriga.

The team, led by UC Berkeley assistant research astronomer Gaspard Duchêne, used a prototype instrument called the Fibered Imager foR Single Telescope (FIRST) that was mounted three years ago on the Shane 3-meter telescope at the University of California Lick Observatories in San Jose.

“This really is a window on a unique combination of contrast and resolution that is not available today,” Duchêne said.