Credit: Optical: NASA/CfA/P.Challis et al; Radio: MIT/ATN/Gaensler & Manchester; X-ray:
NASA/PSU/D. Burrows et al.
A Blast from the Recent Past
The explosion of a massive star in the Large Magellanic Cloud (a satellite
galaxy of the Milky Way) in 1987 provided a great deal of excitement, since
this was the first nearby supernova in more than 400 years. Because of its
proximity to the Milky Way, astronomers were able to determine the identity
of the star that exploded, and have been able to monitor the evolution of
the explosion as it interacts with the interstellar medium. The X-ray
energy band is especially important, since the violent collision of the
supernova ejecta and the interstellar medium generates extremely high
temperatures (of a few million degrees or more) and causes the medium to
glow brightly in X-rays. In addition, the remnant stellar core may also be
a hot neutron star or black hole, which can be best identified by looking
for emitted X-rays. The montage above shows 4 views of the interaction of
the supernova ejecta with a ring of old material which was ejected from the
star about 1000 years before the supernova. The image on the upper left
shows a Hubble
Space Telescope optical image taken 2 February 2000. The image on the
upper right shows a radio image from 9 September 1999 obtained by the Australian Telescope Compact Array.
The image on the lower right shows a Chandra
X-ray image from 17 January 2000, while the image on the lower left is
a Chandra X-ray image from 6 October 1999. The X-ray emission shows
significant variability in a relatively short time, and suggests that more
of the ejecta is plowing into the interstellar medium. As yet there is
no sign of the neutron star or black hole at the center of the ring of hot
gas. The diameter of the ring is about 1 light year, which immediately
suggests that the ejecta is moving at a large fraction of the speed of
light.
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Page Author: Dr. Michael F.
Corcoran
Last modified July 24, 2000
