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Caldwell 44 (NGC 7479)
David Vander Haak

Caldwell 44 (NGC 7479)

Caldwell 44, or NGC 7479, is a barred spiral galaxy discovered in 1784 by astronomer William Herschel. A barred spiral galaxy is a disc of stars with a bar at its core and arms which begin from the edges of this core and spiral outward. The denser core is made up of older stars, and the outer edges are made up of hotter stars that formed more recently and don't last long. There are also often dust lanes in the galaxy that create patterns of blocked light. This particular barred spiral galaxy is approximately 105 million lightyears away, and found in the the Pegasus constellation.

This image of Caldwell 44 is taken more or less face on, so the full disc can be seen. The distance to the object, as previously mentioned, was found to be 105 million lightyears; we find a maximum angular size of 152 arcseconds, which corresponds to a linear size of 77,000 lightyears. As mentioned above, there is a core of older stars, which are not as hot, as can be seen by their yellow color. The outer edges of the arms, coming out from the core and spiraling westward are blue. The blue color of the stars in the arms indicates that the stars in the arms are younger, hotter, more recently formed stars. The image does not clearly show any dust lanes, but if it did, they would appear as darker patterns on the image.

References:

"Spiral Galaxies." Sloan Digital Sky Server. <http://cas.sdss.org/dr5/en/proj/basic/galaxies/spirals.asp>.

Frommert, Hartmut and Kronberg, Christine. "NGC 7479." Students for the Exploration and Development of Space. <http://messier.seds.org/xtra/ngc/n7479.html>

Right Ascension (J2000) 23:04:56.70
Declination (J2000) +12:19:20.0
Filters used B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B, V, and R (6.0s x 5); C (60s x 1)
Date observed October 19, 2012

 

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