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NGC 3646 - Ring Galaxy
Evan Jensen

Ring Galaxy

This is the celestial object NGC 3646, also known as a Ring Galaxy. First one must know what a spiral galaxy is to understand its subset of Ring Galaxy’s. A spiral galaxy is just a swirling disk of gas and dust concentrated around a central cluster of stars known as a bulge. A ring galaxy is a type of spiral galaxy that is less dense then your average spiral galaxy. Meaning that the central matter of the galaxy and the outer ring are the main regions that have density, and you don't have the matter spread throughout, you have a ring of matter missing from the middle. This phenomenon was discovered in 1950 by Art Hoag and believe to be formed when smaller galaxies pass through larger ones and lose their central matter in the process.

In this image again we see the Ring Galaxy, classification number NGC 3646. As you can see this image is at somewhat of a three quarters view angle and captures the central "bulge" and the central ring of the galaxy. As you can see there is also an empty space between the ring and the central bulge of stars thus giving this galaxy its ring like appearance and name. This type of galaxy is also very bright. This is due to the high density of young blue stars that usually make up these galaxies. Another interesting fact about a Ring galaxy is it’s on the opposite end of the spectrum as a Grand Design Galaxy. A Grand Design Galaxy is on that exemplifies that perfect spiral pattern one would tend to expect, while a Ring Galaxy is a spiral galaxy that is far from the perfect spiral.

 

References:

Right Ascension (J2000) 11:21:43.1
Declination (J2000) 20:10:59
Filters used B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B, V, and R (60s); C (60s x 5)
Date observed October 23, 2012

 

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