'Pacman' Nebula Gets Some Teeth

In visible light, the star-forming cloud catalogued as NGC 281 in the constellation of Cassiopeia appears to be chomping through the cosmos, earning it the nickname the "Pacman" nebula after the famous Pac-Man video game of the 1980s. Image Credit: NASA/JPL-Caltech/UCLA. Full image and caption

To visible-light telescopes, this star-forming cloud appears to be chomping through the cosmos, earning it the nickname the "Pacman" nebula, like the famous Pac-Man video game that debuted in 1980. When viewed in infrared light by NASA's Wide-field Infrared Survey Explorer, or WISE, the Pacman takes on a new appearance. In place of its typical, triangle-shaped mouth is a new set of lower, sharp-looking teeth. The Pacman is located at the top of the picture, taking a bite in the direction of the upper left corner.

The teeth are actually pillars where new stars may be forming. These structures were formed when radiation and winds from massive stars in a central cluster blew gas and dust away, leaving only the densest of material in the pillars. The red dots sprinkled throughout the picture are thought to be the youngest stars, still forming in cocoons of dust.

The Pacman nebula, also called NGC 281, is located 9,200 light years away in the constellation Cassiopeia.

This image was made from observations by all four infrared detectors aboard WISE. Blue and cyan (blue-green) represent infrared light at wavelengths of 3.4 and 4.6 microns, respectively, which is primarily from stars, the hottest objects pictured. Green and red represent light at 12 and 22 microns, respectively, which is primarily from warm dust (with the green dust being warmer than the red dust).

JPL is managed for NASA by the California Institute of Technology in Pasadena.

NGC 281: Living the High Life

NGC 281
Credit: X-ray: NASA/CXC/CfA/S.Wolk;
IR: NASA/JPL/CfA/S.Wolk

JPEG (786.7 kb) - Tiff (12.2 MB) - PS (19.6 MB) - More Images

Download Desktop - High-Quality Prints - Image with Scalebar

Zoom-In (flash)

High-mass stars are important because they are responsible for much of the energy pumped into our galaxy over its lifetime. Unfortunately, these stars are poorly understood because they are often found relatively far away and can be obscured by gas and dust. The star cluster NGC 281 is an exception to this rule. It is located about 9,200 light years from Earth and, remarkably, almost 1,000 light years above the plane of the Galaxy, giving astronomers a nearly unfettered view of the star formation within it.

NGC 281 in relation to the Milky Way plane.
Milky Way image by Nick Risinger, skysurvey.org

This composite image of NGC 281 contains X-ray data from Chandra (purple) with infrared observations from Spitzer (red, green, blue). The high-mass stars in NGC 281 drive many aspects of their galactic environment through powerful winds flowing from their surfaces and intense radiation that heats surrounding gas, "boiling it away" into interstellar space. This process results in the formation of large columns of gas and dust, as seen on the left side of the image. These structures likely contain newly forming stars. The eventual deaths of massive stars as supernovas will also seed the galaxy with material and energy.

NGC 281 is known informally as the "Pacman Nebula" because of its appearance in optical images. In optical images the "mouth" of the Pacman character appears dark because of obscuration by dust and gas, but in the infrared Spitzer image the dust in this region glows brightly.

Fast Facts for NGC 281:

Scale: Image is about 18 arcmin across (about 48 light years)
Category: Normal Stars & Star Clusters
Coordinates: (J2000) RA 00h 52m 59.35s | Dec +56° 37' 18.8"
Constellation: Cassiopeia
Observation Date: 3 pointings from 11/10/05-11/12/05
Observation Time: 27 hours 30 min.
Obs. ID: 5424, 7205-7206
Color Code: X-ray (Purple); Infrared (Red, Green, Blue)
Instrument: ACIS
Distance Estimate: About 9,200 light years