domingo, 12 de junio de 2011
IC1805 - Heart Nebulae
A new mosaic from NASA’s newest infrared observatory captures the Heart and Soul nebulae, so named because of their resemblance to hearts — both the Hallmark-card and the blood-pumping variety.
“One is a Valentine’s Day heart, and the other is a surgical heart that you have in your body,” said Ned Wright of the University of California, Los Angeles, who presented the image May 24 at a meeting of the American Astronomical Society.
Since its launch Dec. 14, 2009, the Wide-Field Infrared Survey Explorer has been circling the Earth in a polar orbit and snapping images every 11 seconds. As of Sunday, it has captured 953,880 frames and mapped about 75 percent of the sky, Wright said.
The new image is stitched together from 1,147 individual frames. The exposure took a total of 3½ hours spread over 11 days in February to complete. The nebulae are located in the constellation Cassiopeia, about 6,000 light-years away from Earth.
The image is color-coded to make sense to human eyes, which are blind in the infrared. Blue and cyan represent the shortest wavelengths WISE is sensitive to — 3.4 and 4.6 micrometers — and highlight places where stars are being born. Green light shows small grains of dust that have been heated by starlight and glow at the 12-micrometer band. The longest wavelength, 22 micrometers, is shown in red, capturing larger dust grains.
The bright spot at the top right of the image is an active star-forming region called W3, which Wright studied with a 4-pixel balloon-borne telescope for his Ph.D. thesis in the 1970s. Wright marveled at the difference between the sketched-out contour map he made then and the glowing portrait captured by WISE.
“It’s been an amazing progress in IR astronomy, with cameras growing by a factor of a million in power in just a few decades,” he said.