Wednesday, September 9, 2009
The mission of Atlantis, the shuttle that launched last May to make the final adjustments to the Hubble, is already paying dividends. The shuttle's astronauts installed the Wide Field Camera 3 (WFC3), which snapped this photo of the "Bug" or "Butterfly" planetary nebula.
According to NASA, the star at the center of the nebula first evolved into a huge red-giant star, with a diameter of about 1,000 times that of our Sun. It then lost its extended outer layers. Some of this gas was cast off from its equator at a relatively slow speed, perhaps as low as 20,000 miles an hour, creating the doughnut-shaped ring. Other gas was ejected perpendicular to the ring at higher speeds, producing the elongated "wings" of the butterfly-shaped structure.
Check out the description of this photo and see others at NASA's website.