N132D: An Oxygen Factory in a Nearby Galaxy (Forwarded)

Megan Watzke
Chandra X-ray Center, Cambridge, Mass.
617-496-7998

March 12, 2008

N132D: An Oxygen Factory in a Nearby Galaxy
[http://chandra.harvard.edu/photo/2008/n132d/]

This Chandra X-ray Observatory image shows the debris of a massive star
explosion in the Large Magellanic Cloud, a small galaxy about 160,000
light years from Earth. The supernova remnant (SNR) shown here, N132D, is
the brightest in the Magellanic clouds, and belongs to a rare class of
oxygen-rich remnants. Most of the oxygen that we breathe on Earth is
thought to have come from explosions similar to this one.

The colors in this image show low energy X-rays (red), intermediate energy
X-rays (green) and high energy X-rays (blue). Substantial amounts of
oxygen are detected in this image, particularly in the green regions near
the center of the image. The location of these oxygen-rich areas, detected
in the Chandra image, is generally well matched with the oxygen-rich areas
detected in Hubble Space Telescope images (not shown here). However, the
expanding, ellipse-shaped shell of oxygen seen in N132D is not seen in
either G292.0+1.8 or Puppis A, two oxygen-rich SNRs in the galaxy with
similar ages to N132D (about 3,000 years, ten times older than Cas A). The
origin of this shell is unknown, but it might have been created by a
'nickel bubble' shortly after the supernova explosion, caused by
radioactive energy input from nickel that was created by the explosion.
The existence of such bubbles is predicted by theoretical work.

The ultimate goal of these observations is to constrain the mass of the
star that exploded and to learn more about how massive stars explode and
spread heavy elements like oxygen into surrounding space.