Blue Snowball Planetary Nebula

NGC 7662 - Blue Snowball

NGC7662 (C22) is a planetary nebula in the constellation Andromeda.  As with all planetary nebulae, it's the remnant of a red giant star which has ejected its outer gaseous shell leaving behind a hot, dense, white-dwarf star.   The 13th-magnitude central star can be seen in this image.   It has been estimated that 95% of all stars, including our Sun, will end their lives in this way.  NGC7662 has an estimated distance of 5600 light years and an apparent diameter of 32"x28".   To learn more about these objects and view images of such nebulae from the Hubble Space Telescope (HST) click here.  

   This image is a color composite consisting of individual exposures through white (minus IR), cyan, magenta and yellow filters (WCMY).  The white (luminance) component is from 42, 15-second subexposures.  CMY exposures were: 33x15sec, 30x15sec, and 53x15sec, respectively.  The image was obtained beteen 0605-1411UT on 3October 1999.

Below is the full field surrounding the nebula.

NGC 7662 - The Blue Snowball

The following two Hubble Telescope images depict this planetary nebula.  The first image, in false color, highlights the emission of certain ions in the nebula.  The second image highlights the FLIERs, or Fast Low-Ionization Emission Regions.  These knots of dense gas appear to have been ejected from the central star before it cast off the planetary nebula; however, no astrophysical model has yet explained the existence of such outlying FLIERs.  

NGC 7662 - HST Image                             NGC 7662 - HST Image

The Blue Snowball Planetary Nebula
B. Balick (U. Washington) et al., WFPC2, HST, NASA


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