New Pictures: Planetary Nebulae Shine in X-Ray Vision

Ring of Fire

Image courtesy Joel Kastner et al, NASA/CXC/RIT/STScI

NGC 7662 (pictured) and three dozen other nebulae from the Chandra study offer glimpses of our own sun's likely state several billion years from now. Once their core hydrogen is consumed, sunlike stars expand into red giants, then shed outer layers of gas. Inside these floating shells, the stars' cores contract into white dwarfs.

Just before entering dwarfhood, the core throws off huge amounts of material, which collides with the roughly 10,000-year-old gas bubble left behind by the star's red giant stage.

Hitting the stagnant red-giant shell at a thousand kilometers (621 miles) a second, the new material generates temperatures in the millions of degrees, said Kastner, of Rochester Institute of Technology's Center for Imaging Science. "And the only way you can see that is in the x-ray wavelength."

(Also see "'Soccer Ball' Nebula Discovered by Amateur Astronomer.")

Published October 17, 2012

Eye Candy

Image courtesy Joel Kastner et al, NASA/CXC/RIT/STScI

Tinted purple, x-ray emissions were found in only planetary nebulae younger than 5,000 years, or about 30 percent of the Chandra survey's subjects—including NGC 7009, pictured. It's during this relatively young stage that the cores eject superfast stellar winds that slam into the gas shells, triggering the high-energy x-rays, Kastner believes.

"There are new things we're able to see when we look at this smoky purple light," Kastner explained. "We see the shock waves from this faster material hitting the slower moving material of the gas envelope ... "

The x-ray patterns can also reveal the extent to which nebulae are "polluted with heavier elements from previous generations of stars—traces of carbon, oxygen, neon, and things like that."

Published October 17, 2012

Fading Star

Image courtesy Joel Kastner et al, NASA/CXC/RIT/STScI

Distinct wavelengths in Chandra's new x-ray data help identify the cast-off elements riding a white dwarf's winds, revealing more about the former star's last days (pictured: NGC 6826). "This was material that was participating in fusion, the material from the interior that's not going to be part of the white dwarf ... ," said Kastner, who co-authored the new study, published in the August issue of The Astronomical Journal.

The new data also hint that many of our neighborhood's planetary nebulae have remnants of twin stars at their centers—stars typically outshone by the white dwarfs but detectable at x-ray wavelengths. These close-orbiting companions, the study says, may have an as yet unknown role in shaping the often twisted remains of fading stars.

Published October 17, 2012

More X-Ray Pictures: Hidden Kitten, Quackery, and Beyond

Image by Wilhelm Röntgen, via SSPL/Science Museum/Getty Images

Published October 17, 2012