See starbirth up close
Posted: Thursday, November 05, 2009 7:05 PM by Alan Boyle
NASA / ESA / U. of Va. / STScI / ANU |
Click for video: Hubble's new Wide Field Camera 3 captures a detailed view of
starbirth in the spiral galaxy M83. Click on the image to watch a zoom-in video.
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The Hubble Space Telescope's new wide-field camera has sent down a picture showing how the "assembly line" of starbirth works in a nearby spiral galaxy.
The galaxy is a stunner in its own right: M83, also known as the Southern Pinwheel, is 15 million light-years from Earth lies in the constellation Hydra. The galaxy can just barely be made out with the naked eye under optimal conditions, but the telescope view reveals a spectacular face-on spiral ... hence the "Pinwheel" label.
Hubble's Wide Field Camera 3, which was installed in May during the space shuttle Atlantis' final visit to the orbiting observatory, focuses on one of the pinwheel's spiral arms. Image data from five different filters, ranging from ultraviolet to near-infrared, were combined to create the big picture released today, said Ray Villard, a spokesman for the Baltimore-based Space Telescope Science Institute (and author of the Cosmic Ray blog).
"This is wonderful for really sorting out the details of what's happening in the picture," he told me.
You could regard the picture as a kind of time machine. Toward the right side of the image, near the dense core, newborn star clusters are being squeezed into existence amid the murk. The stars are swathed in cocoons of dust and reddish-glowing hydrogen gas.
When you turn your eyes to the left side of the image, the star-formation process has advanced further along the timeline: Radiation from the hot, young, blue stars has blown away the surrounding gas and dust, creating bubbles of open space that lets the light shine bright. In today's advisory, the Hubble team describes this as a "colorful 'Swiss cheese' appearance."
"You're really seeing an assembly line in wonderful detail," Villard said. "This is a prime target for getting a God's-eye view of star formation."
Astronomers have also spotted the remains of about 60 supernova blasts, about five times as many as had been seen in previous images of the region. Those blast sites are harder to point out in the image, but the scientists can analyze the chemical signatures of the remnants to figure out what the exploded stars were made of.
The study can shed new light on the process by which heavier chemical elements are created by one generation of stars and passed on to the next generation. Without that process, the elements essential to life as we know it (such as carbon and oxygen) would not exist.
Villard said Wide Field Camera 3 and Hubble's other instruments are primed to take on a new batch of scientific challenges, thanks to May's extreme makeover. "The instruments are all working fine," he said. "Hubble is in full science mode."
One of the goals in Hubble's sights is to identify objects on the very edge of the observable universe. This year, NASA's Swift satellite spotted a gamma-ray burst that is thought to have occurred when the cosmos was only 630 million years old, setting a distance record with a redshift of 8.2. (An object's spectral redshift serves as a cosmic yardstick: The bigger the redshift, the farther away the object is.)
"We hope eventually to say we've found something beyond 9," Villard said. That would mean the light from the object began its journey when the universe was a mere 550 million years old.
Nailing down the evidence for an object that far away isn't easy. "You're into the very dim and mysterious early formative years, so how you interpret what you have and how you convince yourself that it's real is tricky," Villard said. But I have a feeling that the Hubble Space Telescope and the astronomers who use it are up to the challenge.
For a closer look at the Southern Pinwheel, check out the Hubble team's zoomable view. And to see more of the Hubble team's feats, check out these slideshows:
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