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The Ring Nebula

 ringrvbnm72.jpg (11527 bytes) M57, the Ring Nebula, in LYRA.

The central star of the ring nebula has changed from a star bigger than our Sun to a white dwarf star about the size of Earth!  The star is surrounded by a cylinder of gases and dust which were ejected from the star.  First the star puffed out, then it collapsed to a hot white dwarf, leaving behind the gases and dust.  This nebula and its white dwarf star are about 2300 light years away.  The nebula is approximately a light year across.

Nebulae like the ring nebula are called 'planetary nebulae' because they seemed round like planets when first viewed through telescopes.  They are one of the final stages in a star's 'life cycle', usually containing a small, hot, white dwarf  star in the center. 

Our Sun may turn into a white dwarf someday, but not at least for another five billion (5,000,000,000) years!  Our Sun will live about ten billion years.  Now, it is only half way through its 'life' time.


Filters reveal glowing ionized gases:  Hydrogen and Nitrogen, Oxygen, Helium
ringrv2b4.jpg (18779 bytes)   
The  radiation from the white dwarf star is causing the gases around the star to ionize and glow.  Which gases are which?

 HOU Image Processing

Using HOU Image Processing software, open all three images.  M57b.fts, M57v.fts, and M57r.fts.

Multiplying Counts .... to compare colors
The ccd camera is most sensitive to red light.  In order to compensate for this sensitivity, either the images can be taken with varied exposure times or the counts across the images can be multiplied. 

To approximately equalize the color of these filtered images and account for the red sensitivity of the ccd chip: 

1.  Multiply the b image by 4; save as m57b4.fts
2.  Multiply the v image by 2; save as m57v2.fts 
3.  Do not change the m57r.fts image. 

ringbwrvb.jpg (10334 bytes) Combine the images to see all the light gathered by the filters.

1.  Click on m57r.fts 
2.  Go to Manipulation Add, Displayed image, Select m57v2.fts. 
3.  Again, go to Manipulation Add, Displayed image, Select m57b4.fts. 
4.  Save image as m57rv2b4.fts

Download images of the ring nebula, m57orig and m57readytoadd for this activity. The M57 images were taken at Yerkes Observatory by Michael Clark, Frank Mills, and Bill McCoy, on June 25, 1999.

Download more images of planetary nebulae: m57, taken for the NFSI teachers; and ngc7048, taken by Frank Mills and Kevin McCarron on July 8,1999.

astroline.jpg (9796 bytes)

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