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.