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NASA's Chandra X-ray Observatory
images a young supernova blast wave.
May
11, 2000 -- Two images made by NASA's Chandra X-ray
Observatory, one in October 1999, the other in January
2000, show for the first time the full impact of the
actual blast wave from Supernova 1987A (SN1987A). The
observations are the first time that X-rays from a
shock wave have been imaged at such an early stage of
a supernova explosion.
Right: This Chandra X-ray image of
SN 1987A made in January 2000 shows an expanding shell
of hot gas produced by the supernova explosion.
Recent observations of SN 1987A with
the Hubble Space Telescope revealed gradually
brightening hot spots from a ring of matter ejected by
the star thousands of years before it exploded.
Chandra's X-ray images show the cause for this
brightening ring. A shock wave is smashing into
portions of the ring at a speed of 10 million miles
per hour (4,500 kilometers per second). The gas behind
the shock wave has a temperature of about ten million
degrees Celsius, and is visible only with an X-ray
telescope.
"With Hubble we heard the whistle
from the oncoming train," said David Burrows of
Pennsylvania State University, University Park, the
leader of the team of scientists involved in analyzing
the Chandra data on SN 1987A. "Now, with Chandra,
we can see the train."
The X-ray observations appear to
confirm the general outlines of a model developed by
team member Richard McCray of the University of
Colorado, Boulder, and others, which holds that a
shock wave has been moving out ahead of the debris
expelled by the explosion. As this shock wave collides
with material outside the ring, it heats it to
millions of degrees. "We are witnessing the
birth of a supernova remnant for the first
time," McCray said.
Left:
This two frame animation is an excerpt from a more
detailed online movie illustrating the events
following the supernova 1987A outburst. The blue ring
is previously observed material ejected from the star
thousands of years ago. The expanding orange and
yellow shell is multimillion degree, X-ray emitting
gas produced by the explosion. Portions of the blue
ring light up when struck by the X-ray shell.
Quicktime animations: High
Res (3228090 Bytes) | Low
Res (1035129 Bytes)
The Chandra images clearly show the
previously unseen, shock-heated matter just inside the
optical ring. Comparison with observations made with
Chandra in October and January, and with Hubble in
February 2000, show that the X-ray emission peaks
close to the newly discovered optical hot spots, and
indicate that the wave is beginning to hit the ring.
In the next few years, the shock
wave will light up still more material in the ring,
and an inward moving, or reverse, shock wave will heat
the material ejected in the explosion itself.
"The supernova is digging up its own past,"
said McCray.
Right:
Chandra/Hubble composite image of SN1987A. This
Chandra X-ray image of SN 1987A made in January 2000
shows an expanding shell of hot gas produced by the
supernova explosion. The colors represent different
intensities of X-ray emission, with white being the
brightest. Also shown are the contours from a Hubble
Space Telescope optical image taken on 2 February
2000. Scale: The optical ring is 1.2 x 1.6 arcsec,
corresponding to 1.0 x 1.3 light years.
The observations were made on
October 6, 1999, using the Advanced CCD Imaging
Spectrometer (ACIS) and the High Energy Transmission
Grating, and again on January 17, 2000, using ACIS.
Other members of the team were Eli Michael of the
University of Colorado; Dr. Una Hwang, Dr. Steven Holt
and Dr. Rob Petre of NASA's Goddard Space Flight
Center in Greenbelt, MD; and Professors Gordon Garmire
and John Nousek of Pennsylvania State University. The
results will be published in an upcoming issue of the
Astrophysical Journal.
The ACIS instrument was built for
NASA by the Massachusetts Institute of Technology,
Cambridge, and Pennsylvania State University. The High
Energy Transmission Grating was built by the
Massachusetts Institute of Technology. NASA's Marshall
Space Flight Center in Huntsville, AL, manages the
Chandra program. TRW, Inc., Redondo Beach, CA, is the
prime contractor for the spacecraft. The Smithsonian's
Chandra X-ray Center controls science and flight
operations from Cambridge, MA.
Related Links:
X-Rays
- Another Form of Light - the basics of
X-rays from the Chandra home page at Harvard
X-ray
Astronomy Field Guide: Supernovae and Supernova
Remnants - from the Harvard Center for
Astrophysics
Chandra
home page -from Harvard
Chandra
News -from NASA
More pictures
and animations
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