The information provided on this page was originally made available as a Photo Release at the 193rd American Astronomical Society Meeting in Austin, TX, Jan. 9, 1999. It has been updated for general use since that time.
Wow! What am I looking at?
This is an image of a tiny section of the Cygnus Loop supernova remnant, obtained in November 1997 with the Hubble Space Telescope using the Wide Field and Planetary Camera 2 instrument.
These glowing gaseous filaments trace the location of a 5-10,000 year old supernova blast wave as it plows into gas in interstellar space at 170 kilometers per second (380,000 miles per hour). The filaments are on the edge of a huge expanding bubble of hot gas known as the Cygnus Loop, a supernova remnant some 440 pc (1440 light years) distant in the constellation Cygnus the Swan. In this picture, the shock front is moving upward and the supernova explosion was at a distant location out the bottom of the picture. This image was obtained by the Hubble Space Telescope in November 1997 using the Wide Field and Planetary Camera 2 instrument and shows details on a scale 10 times finer than available from ground based telescopes. To Hubble's eye, the shock front is seen as a gently rolling, nearly edge-on sheet of gas lying more or less along the line of sight and glowing in the light of the optical hydrogen-alpha emission line. When seen exactly edge-on, the shock wave thickness is extremely narrow, reducing to less than one camera pixel, or only one part in 50,000 of the radius of the supernova remnant!
The Hubble Space Telescope's greatest strength is in examining very tiny pieces of the sky in great detail. To place this image in context, the European Hubble Coordinating Facility has done a very nice photo release showing where the filament is located in the much larger Cygnus Loop supernova remnant. These can be viewed HERE.
I have also posted a middle-school level exercise that allows one to use these data to calculate the distance to the Cygnus Loop from the mption of the filament over time. This can be found HERE.
Displaying astronomical images such as this one in different ways sometimes shows different subtleties. Below are shown samples of different displays--color, white on black, or black on white, and either "linear" or "logarithmic" translation of detected photons into displayed intensity of light. You can inspect the full image in the desired format (gif, tif, jpg or postscript) simply by clicking the appropriate link below each sample. If any of these are used in a publication, please include the following photo credit line. Enjoy!
PHOTO CREDIT: William P. Blair and Ravi Sankrit (Johns Hopkins University), and NASA.
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If you have questions or comments, please let me know.
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Last updated: August 2008.
Bill Blair ([email protected])
