Turbulent Nursery: Young Stars in Nearby Nebula Already Exploding
Supernova explosions mark the violent end for many massive stars, but for some that end comes shortly after the beginning.
A detailed survey of the so-called Carina Nebula, a star-forming region relatively close to our solar system, is turning up evidence that numerous stars have already gone supernova there, and that many more may do the same in the millions of years to come. "Carina is a huge stellar nursery really just down the block in galactic terms at 7,500 light-years," Leisa Townsley of Pennsylvania State University (PSU) said here in a press briefing at the semiannual meeting of the American Astronomical Society. Townsley leads the Chandra Carina Complex Project (CCCP), a campaign with the Chandra X-ray Observatory to make a detailed x-ray map of the nebula.
A previous x-ray observatory had located about 40 individual pointlike x-ray sources in the nebula. The CCCP project, on the other hand, has resolved more than 14,000 sources, most of them young stars, just a few million years in age. But the survey also found that the nebula is filled with a diffuse x-ray haze, probably generated by powerful winds from the stars there or by recently exploded stars. "This is very interesting because this is a stellar nursery, this is where stars are born," Townsley said. A firmer line of evidence for supernovae in Carina came from another researcher's 2009 identification of an ultradense stellar remnant called a neutron star there. Those objects are produced in supernovae, and CCCP has now found several more possible neutron stars.
Carina is also looking promising as a destination for stars to explode in the future. PSU postdoctoral researcher Matt Povich showed how a broad swath of dust [infrared imagery, red in image above] obscures many of the biggest, brightest stars in the nebula in visible light. "We're missing the brightest and most luminous stars, the ones that are going to become supernovae in the future," he said. X-rays can pass through dust, allowing astronomers a better look at the stars in the nebula.
To the 140 big, bright stars that were known in the nebula previously, CCCP researchers have now added nearly 100 more. "Ninety-four of them are preferentially in the regions that are obscured by dust or located far away from these very famous clusters" and hence have remained unseen, Povich said. "This suggests that there are twice as many massive stars in Carina as we used to think there were, and there will be twice as many supernovae in the future."
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