Sweeping X-ray Imaging Survey of Dying Stars is ‘Uncharted Territory'

RIT astronomer Joel Kastner heads international team using the Chandra X-ray Observatory

X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI

Four planetary nebulae are shown here from the first systematic survey of these dying, Sun-like stars in the solar neighborhood using the Chandra X-Ray Observatory. X-ray emission from Chandra is colored purple and optical emission from the Hubble Space Telescope is colored red, green and blue. The nebulae are NGC 6543, also known as the Cat's Eye (top left), NGC 7662 (top right), NGC 7009 (bottom left) and NGC 6826 (bottom right).

The death throes of dying stars are the focus of a sweeping new survey using NASA’s Chandra X-ray satellite observatory.

More than two dozen astronomers have aligned their research goals to use Chandra to image a set of dying stars in the neighborhood of the Sun. The resulting X-ray images of these dying stars—called planetary nebulae—are shedding light on the violent “end game” of a Sun-like star’s life.

The research team, led by Joel Kastner from Rochester Institute of Technology, won seven days of observing time with Chandra in 2011–12 to survey and image nearly two dozen relatively nearby planetary nebulae, resulting in the most comprehensive X-ray survey to date for such objects.

The same team recently won an eight-day time award with Chandra to continue its observing program, and will begin collecting new X-ray data later this year.

Both the previous and upcoming series of observations are part of the Chandra X-ray Survey of Planetary Nebulae (ChanPlaNS). Leaders in planetary nebula astronomy from seven countries joined forces to win the large Chandra observing time awards.

A planetary nebula is a dying star (recently a “red giant”) that has cast off its outer layers. The newly exposed, hot core of the star (which will eventually become a “white dwarf” star) illuminates these ejected layers, while the core’s fast winds sculpt the material into a variety of shapes. The resulting dazzling objects, bearing names like Cat’s Eye, Lemon Slice and Blue Snowball, are favorite targets of optical and near-infrared telescopes.

“Planetary nebulae have provided astrophysicists with dying star ‘laboratories’ for more than a century,” Kastner says. “They provide test beds for theories of stellar evolution and give us insight into the origin of heavy elements in the universe and on Earth. Yet we still don’t fully understand why they take on such a dazzling variety of shapes.”

The widespread debate among astrophysicists concerning the planetary nebula shaping process led Kastner and postdoctoral fellow Rodolfo Montez Jr. to organize their colleagues to request a large allocation of X-ray satellite observing time to investigate the processes of stellar death and wind collisions in X-rays.

“An X-ray survey of this kind is completely uncharted territory in the planetary nebula world,” Kastner adds. “Astronomers working in this area agreed that we need large quantities of time to look at as many planetary nebulae as possible, specifically with Chandra.” (more)http://www.rit.edu/news/story.php?id=49444