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NGC 205: M110
Jessa Roubos

NGC 205

NGC 205 is a dwarf elliptical galaxy. This type of Galaxy was first discovered by Dr. Shapley.  It is labeled dwarf because it only holds less than a billion stars which is about as much as a globular cluster, not a full sized galaxy or a giant galaxy which contains trillions of stars.  However the difference that makes this a galaxy still is that it takes up a much larger space with the same general amount of stars. In fact a very small dwarf elliptical galaxy could have fewer than 1 million stars and be smaller than 1 kiloparsecs. These elliptical galaxies are often found revolving around a larger galaxy called a “host galaxy”.  Elliptical galaxies have no spiral arms (like spiral galaxies) or any internal structure besides the nucleus at the center. Elliptical galaxies are sorted on a shape range with E0 being the most spherical and E7 being the most elongated, or disk shaped.   Important tell-tale characteristics of dwarf elliptical are low surface brightness and smooth light distribution. This type of galaxy contains little to no cool gas and dust. And in almost every case there is no emission from hydrogen gas at all, which is surprising because the atmosphere was originally mostly hydrogen.

 

NGC 205 was discovered by Caroline Herschel on August 27, 1783. However it was Kenneth Glyn Jones in 1967 that had it assigned to a Messier number of 110. This dwarf elliptical galaxy is revolving around the very famous Andromeda Galaxy. The Andromeda Galaxy is 2.54 million light years away so it is safe to say that this distance is about the same, give or take where it is in its revolution. So if the distance to this galaxy is estimated to be about 2.54 million light years away; we find a maximum angular size of 135 arc seconds by 230 arc seconds giving us a linear size of 1700 by 2800 light years in linear size. In most dwarf elliptical galaxies the nuclei, or center, is the same age as the surrounding galaxy. However, in NGC 205 the nucleus is much different from others because it is young in comparison and shows hints of star formation. In consistancy with that, there is a few dust formations shown on the image above which is also unusual for elliptical galaxies. The dust is shown as slighly dark spots on the image. One is on the upper left side of the galaxie, and two more are near the bottom of the galaxy. The shape of NGC 205 is in the E5 class, meaning that it is slightly more elongated than most. As stated above there is a smooth light distribution all around as it gradually gets fainter further away from the nucleus(the bright yellow spot in the center).

 

References:

Caldwell, Nelson. Encyclopedia of Astronomy & Astrophysics. Comp. P. Murdin. IOP, 2006. Print. Dwarf Elliptical Galaxies.<http://www.astro.caltech.edu/~george/ay21/eaa/eaa-de.pdf

McMillan, Steve. Chaisson, Eric. Astronomy Today. Person Addison-Wesley, 2008. 7th edition

 

Right Ascension (J2000) 00:40:22
Declination (J2000) 41:41:06
Filters used B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B, V, C,and R (60s x 5)
Date observed October 13, 2011

 

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