Abell 39

Click on image for larger version.

Abell 39 is perhaps one of the most perfect examples of a spherical planetary nebula in the galaxy. As expected, a sphere of gas will show a brighter limb ("edge") since that line of sight has more gas than the view through the center (two layers) of the bubble. This one is unfortunately very faint and subtle details of the bubble require a larger telescope (or very long exposures) to bring out. Abell 39 is approximately 5 light years across and 7,000 light years away. Note the myriad of background galaxies in the image- especially through the transparent sphere of gas. Also note that the central star is distinctly blue-white in color. A blue-white color indicates that the central star (white dwarf) is very hot. It emits copius amounts of UV radiation which excite the surrounding gas and make it flouresce its green- blue color. Compare this image with another image (narrowband) of Abell 39 taken at the 3.5m WIYN telescope.


20in RC Optical Systems telescope Operating at f/8.4
Paramount ME Robotic Telescope Mount
SBIG ST10XME CCD camera with color filter wheel

L R G B color production was used to create this image.

Luminance = 180 minutes binned 1x1
Red = 20 minutes binned 3x3
Green = 20 minutes binned 3x3
Blue = 20 minutes binned 3x3

  • Aggressive smoothing was applied to this image in order to diminish the noisy appearence of the nebula. This was done at the expense of resolution; however, the smoother image permitted a brighter image.
  • Minimum credit line: Adam Block/NOAO/AURA/NSF


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    Updated: 5/1/2003