This trio of ghostly images from NASA's Spitzer Space Telescope shows the disembodied remains of dying stars called planetary nebulas. Planetary nebulas are a late stage in a sun-like star's life, when its outer layers have sloughed off and are lit up by ultraviolet light from the central star. They come in a variety of shapes, as indicated by these three spooky structures. In all of the images, infrared light at wavelengths of 3.6 microns is rendered in blue, 4.5 microns in green, and 8.0 microns in red. Credit: NASA/JPL-Caltech/J.
In the spirit of Halloween, scientists are releasing a trio of stellar ghosts caught in infrared light by NASA's Spitzer Space Telescope. All three spooky structures, called planetary nebulas, are in fact material ejected from dying stars. As death beckoned, the stars' wispy bits and pieces were blown into outer space.
"Some might
call the images haunting," said Joseph Hora of the Harvard-Smithsonian
Center for Astrophysics, Cambridge, Mass., principal investigator of the
Spitzer observing program. "We look to the pictures for a sense of the
history of the stars' mass loss, and to learn how they evolved over
time."
All stars about the mass of our sun will die similarly
ethereal deaths. As sun-like stars grow old, billions of years after
their inception, they run out of fuel in their cores and puff up into
red, giant stars, aptly named "red giants." The stars eventually cast
off their outer layers, which expand away from the star. When
ultraviolet light from the core of a dying star energizes the ejected
layers, the billowy material glows, bringing their beautiful shapes to
light.
These objects in their final death throes, the planetary
nebulas, were named erroneously after their resemblance to planets by
William Herschel in 1785. They come in an array of shapes, as
illustrated by the three highlighted here in infrared images from
Spitzer. The ghostly material will linger for only a few thousand years
before ultimately fading into the dark night.
The
brain-like orb called PMR 1 has been nicknamed the "Exposed Cranium"
nebula by Spitzer scientists. This planetary nebula, located roughly
5,000 light-years away in the Vela constellation, is host to a hot,
massive dying star that is rapidly disintegrating, losing its mass. The
nebula's insides, which appear mushy and red in this view, are made up
primarily of ionized gas, while the outer green shell is cooler,
consisting of glowing hydrogen molecules.
The
Ghost of Jupiter, also known as NGC 3242, is located roughly 1,400
light-years away in the constellation Hydra. Spitzer's infrared view
shows off the cooler outer halo of the dying star, colored here in red.
Also evident are concentric rings around the object, the result of
material being tossed out periodically during the star's fitful death.
This
planetary nebula, known as NGC 650, or the Little Dumbbell, is about
2,500 light-years from Earth in the Perseus constellation. Unlike the
other spherical nebulas, it has a bipolar or butterfly shape due to a
"waist," or disk, of thick material, running from lower left to upper
right. Fast winds blow material away from the star, above and below this
dusty disk. The ghoulish green and red clouds are from glowing hydrogen
molecules. The green area is hotter than the red.
NASA's Jet
Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space
Telescope mission for NASA's Science Mission Directorate, Washington.
Science operations are conducted at the Spitzer Science Center at the
California Institute of Technology in Pasadena. Spacecraft operations
are based at Lockheed Martin Space Systems Company, Littleton, Colorado.
Data are archived at the Infrared Science Archive housed at the
Infrared Processing and Analysis Center at Caltech. Caltech manages JPL
for NASA.
Source: NASA's Spitzer Space Telescope
