NASA’s Chandra X-Ray telescope mission has released a new set of images of planetary nebulae.
Chandra has a very nice gallery of images of local (<5000 light years) planetary nebulae, which are formed as a star turns into a Red Giant, shedding its out layers as it ages.
The images are composited, with purple being the x-ray spectrum reading detected by Chandra, and all other colours provided by optical-spectrum scopes. NASA say that since none of the observed nebulae have outer limits older than 5000 years that this could be typical of the timescale of this event in stellar evolution.
About half of the planetary nebulae in the study show X-ray point sources in the center, and all but one of these point sources show high energy X-rays that may be caused by a companion star, suggesting that a high frequency of central stars responsible for ejecting planetary nebulae have companions.
These results were published in the August 2012 issue of The Astronomical Journal. The first two authors are Joel Kastner and Rodolfo Montez Jr. of the Rochester Institute of Technology in New York, accompanied by 23 co-authors.