A star with jets?

Beta Lyrae ranks as one of the most widely studied stars in the heavens. Historical observations of this binary system, which consists of one star that donates mass to a disk of material encircling a companion, date to 1785. Now, a shuttleborne telescope has given astronomers their first three-dimensional view of Beta Lyrae. The data hint that jets of hot gas squirt out of the poles of the star within the disk.

Astronomers can't view the interior of Beta Lyrae directly because the disk blocks it, notes Kenneth H. Nordsieck of the University of Wisconsin-Madison. But gas lying above and below the poles of the central star polarizes light from Beta Lyrae, reflecting some of it toward Earth and enabling scientists to peek inside the binary system.

In conjunction with ground-based observations of polarized visible light, data from the Wisconsin Ultraviolet Photopolarimeter Experiment, which flew aboard the Astro 2 Observatory last March, revealed the presence of such polar gas clouds. Nordsieck says that by analogy with much larger systems that have accretion disks, such as quasars, the clouds represent gas jets propelled by Beta Lyrae's disk.