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Astronomical Observatory: Cool Images

Astr110 Photography Projects, Fall 2006

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Spiral Galaxy (M77), Loren Heacock

Helix Nebula

This picture was taken October 19, 2006. This picture contains the spiral galaxy M77.  In fact, it is one of the largest known spiral galaxies, with the bright part going out 120,000 light years and the faintest parts going out to 170,000 light years out.  M77 is 60 million light years away from the Earth.  The inner disc is estimated at 27 billion solar masses, while the entire galaxy is estimated having a mass of 1 trillion solar masses.  One feature of this galaxy is the form of broad emission lines showing that giant gas clouds are moving out of the nucleus at a tremendous velocity.  There needs to be an enormous energy source to create this velocity.  Using an infrared telescope a small cluster of stars were found only 12 light years in diameter with 100 light year extensions which was decided the enormous source of energy.  M77 is the dominant feature of a small group of galaxies. 

It has a bright center with two large spiral arms coming out from the center.  This bright cent appears to have a yellowish tint.  Meanwhile the two spiral arms seem to have more of a bluish color. This means that the inner stars are cooler while the stars on the spiral arms are hotter. Also blueish stars tend to be young stars while yellowish stars tend to be older. This means that the spiral arms contain newer stars while the inner core has been there for a much longer time.   It appears that there is large faint disc that would be the outskirts of the galaxy which surrounds the bright center and spiral arms.  M77 has a angular diameter of 360 arcsec. Using the small angle formula I figured the galaxy to have a diameter of 104,720 light years.  This is a bit smaller then the actual diameter.


Right Ascension (J2000) 2:42.7
Declination (J2000) -00:01
Filters used blue(B), green(V), red(R), and clear(C)
Exposure time per filter 5x60 seconds in CBVR
Date observed

October 19, 2006` (CBVR)





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