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Triangulum Galaxy (NGC 598) & Caldwell 30 (NGC 7331)
Mark Rowe & Dave Potts

Triangulum Galaxy - Mark Rowe Caldwell 30 - Dave Potts

 A Spiral galaxy is a galaxy with a flattened disk and nuclear bulge and also contains spiral arms. Besides only containing stars there is also a large interstellar cloud of gas and dusk. When looking at an image you will notice that there is a large galactic halo that surrounds the disk. Spiral Galaxies range from 10,000 to 300,000 light-years in diameter. And the mass is often between 1 Billi0n to 500 Billion solar masses. Some common examples of Spiral Galaxies are our own Milky Way Galaxy as well as Andromeda Galaxy.

The Triangulum galaxy is a neighbor to a far greater galaxy Andromeda Galaxy. It is catalogued as Messier 33 or NGC 598 It is sometimes referred to as the Pinwheel Galaxy which is a nickname it shares with Messier 101. The Triangulum galaxy was first discovered around 1654 and then independently rediscovered by Charles Messier in 1764. It is around 3 million light years away. It is one of the most distant permanent objects that can be viewed with the naked eye Looking at the image that I have captured we can see in the lower left of the galaxy is actually an enormous complex star birth region. In the Triangulum galaxy there is roughly 40 Billion stars and the size of this galaxy is roughly 60,000 LY in diameter. Because of the size of the diameter it is the third largest member of the local group of galaxies. The disk of Triangulum has an estimated mass of 3-6x10^9 solar masses. When we look at the picture we notice that there is a lack of a bar-shaped structure. When we are looking at the arms we notice that the arms are loosely wound.

The Caldwell 30 galaxy is also called NGC 7331 and is one of the brightest galaxies in a group known as the Deer Lick group, and one of the brightest galaxies not included in Messier's catalogue. It is found in the Constellation Pegasus, and was found by astronomer William Herschel in 1784. This galaxy is commonly referred to as The Miliky-Way's twin due to it's similarity in size and shape. The diameter of the galaxy is about 100,000 LY. The bulge of this galaxy contains primarily older stars, and the ring contains a large amount of gas and newborn stars. It's thought that at the central bulge the galaxy contains either a large number of massive stars or a black hole similar in size to that found in the center of the Milky-Way galaxy. The ring around the central bulge of the Caldwell galaxy is full of gases and is an ideal location for new stars to be born. The large number of new stars in this ring gives it its yellowish color.

When looking at and comparing our two galaxies one thing to notice is that both of the galaxies we choose were spiral galaxies. Both galaxies are fairly large in size and are able to be observed from earth by either the naked eye or small telescopes. When you look towards the center of the galaxy towards the bulge one can see that both bulges appear to be yellowish in color. Another thing that is similar with these galaxies is that it seems as though both galaxies have regions where stars are being formed. From our research we were able to find that they were both part of constellations.

One thing that we noticed when looking at the differences was the huge difference in distance. Triangulum Galaxy was roughly only 3 million light years from earth where as Caldwell 30 was over 40 million light years from earth. Another difference was the fact that the Triangulum Galaxy is considered part of a local group of galaxies that also consist of the Milky way and Andromeda Galaxy. Another major difference is that the central bulge in the Caldwell 30 galaxy rotates in the opposite direction as the rest of the disk, while the Triangulum Galaxy rotates all in one direction like most galaxies do. The number of stars within the Caldwell galaxy is about 10 times greater than the Triangulum galaxy.

 

References:

"Messier 33." Messier Object 33. Web. 11 Dec. 2015.

Darling, David. "Triangulum Galaxy (M33, NGC 598)." Triangulum Galaxy (M33, NGC 598). Web. 11 Dec. 2015.

"NGC 7331: A Large Spiral Galaxy." NGC 7331: A Large Spiral Galaxy. Web. 11 Dec. 2015.

"Pegasus Constellation." Constellation Guide. Web. 11 Dec. 2015.

"Seeing Double: Spitzer Captures Our Galaxy's Twin." NASA/JPL. Web. 11 Dec. 2015.

 

Object NGC 598 NGC 7331
Right Ascension (J2000) 01:33:51 22 37 05.10
Declination (J2000) +30:39:28 +34 25 13.0
Filters used B (Blue), C (Clear), R (Red), V (Green) B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B (195s), V (120s), and R (180s); C (195s) B (195), V (165), and R (150s); C (165s)
Image dimension 997x736 pixels; 21.6x15.946 arc minutes 1092 x 736 pixels; 19.5x21.2 arc minutes
Date/time observed September 29ths 2015, 4:39 UT October 1st, 2015, 3:06 UT

 

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