"It's not often you get a chance to catch stars in the act," says Karl Stapelfeldt, an astronomer at NASA's Jet Propulsion Laboratory and a member of the team.
The ongoing study has already yielded an intimate look at how stars grow up.Images taken over a five-year period show that, like small children, the stars' appearance changed radically in a matter of months.In a time-lapse movie available at the Space Telescope Science Institute's
Web site, a bubble of gas nearly 60 billion miles in length escapes from XZ Tauri.
"We don't really know what this is," says Stapelfeldt
, who hopes that another observation of the star this winter will help clear up that mystery.
The second star, HH 30, appears as two flat discs, with jets of gas erupting from it at up to 600,000 miles per hour.The discs are clouds of dust that block light coming directly from the star but are brightened by its reflection."If you look closely at the discs and ignore the jets, you can see light shifting within them," Stapelfeldt
says.The star and the inner part of the discs appear to be illuminating the outer part of the discs "like a lighthouse illuminates a cloud with its beam.The beam rotates, and the clouds seem to brighten and then fade."This lighthouse effect seems to be rotating between once every few days and once a year.No one has ever observed this phenomenon before, and the team hopes to clarify what's happening with more Hubble time.
Although this may look like a tempestuous nursery, colossal gas bubbles and jets are just normal celestial growing pains for infant stars.