LONG BEACH, Calif. (Jan. 7) — A total of 14 young stars racing through clouds of gas like bullets, creating brilliant arrowhead structures and tails of glowing gas, have been revealed by NASA's Hubble Space Telescope. They represent a new type of runaway stars, scientists say.

The discovery of the speedy stars by Hubble, announced here today at the 213th meeting of the American Astronomical Society, came as something of a shock to the astronomers who found them.

"We think we have found a new class of bright, high-velocity stellar interlopers," said study leader Raghvendra Sahai of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Finding these stars is a complete surprise because we were not looking for them. When I first saw the images, I said 'Wow. This is like a bullet speeding through the interstellar medium.'"

The arrowhead structures, or bow shocks, seen in front of the stars are formed when the stars' powerful stellar winds (streams of neutral or charged gas that flow from the stars) slam into the surrounding dense gas, like a speeding boat pushing through water on a lake.