Astr111 Photography Projects, Spring 2007

M95 Spiral Galaxy (NGC 3351), Eric T. Weaver

M95 (which stands for Messier 95) is a barred spiral type of spiral galaxy, located in the Leo constellation, and is located 38 million light years away. It has an angular size of 4' (meaning 4 arc minutes) and a linear size of 43, 923 light-years. M95 is a type SBb barred spiral galaxy, meaning that its "arms" are neither tightly bound or loosely bound, but somewhere in between. The arms of M95 are almost completely circular. The bar that so names these types of spiral galaxies are comprised of stars. These bars generally have an effect on the motions of stars, the interstellar gasses within galaxies, and even the spiral arms. The bars are thought to be a temporary phenomenon in the life of spiral galaxies, the bar structure decaying over time transforming the galaxy from a barred spiral to a "regular" spiral pattern galaxy. M95 was discovered on March 20, 1781 by Pierre Mechain.

In this image of M95, the center, or bar structure, and the circular spiraled arms are clearly visible. The arms are visible as being at a middle distance from the center of the galaxy, neither being tightly or loosely bound to the galaxy (as is common among barred spiral galaxies). While the most common color in this image is a light yellow, a faint blue lining is visible within the arms of the galaxy. This means that the arms have a slightly higher temperature than the rest of the galaxy. The arms swirling about the galaxy are like waves circling the bar of the ga laky (in other words, there are no "arms" in the very center of the galaxy). As the arms grow more dense, new, young stars are formed. This explains the bright blue coloration found amidst the arms of this galaxy.

References:
Frommert, Hartmut and Kronberg, Christine. "NGC 3351." M95 <http://www.seds.org/messier/m/m095.html>

www.wikipedia.com "M95" <http://en.wikipedia.org/wiki/Spiral_Galaxy_M95>.