- M 94 (NGC 4736)
We see M 94 (NGC 4736) face-on. While classified as a spiral galaxy, different waves of star formation have divided the overall structure into zones with marked differences in appearance. At its center, M 94 has a bright starlike core that is easily visible in binoculars. Around this core is a circular zone of older, redder stars extending out to a radius of around 0.5 arc-minutes. Outside this central region, the dynamics of the galaxy's rotation cause interstellar matter to be compressed to trigger the formation of many new stars. This "starburst" region can be seen in the image as the bright, turbulent-looking ring circling the darker central zone. Outside this starburst region, the structure of the galaxy's disk looks relatively uniform (no obvious spiral arms), with traces of the spiral structure indicated by darker dust lanes. There is little new star formation in this zone. At around 3.5 arc-minutes from the center, the edge of this zone appears fairly abrupt, with mostly darkness beyond the edge. However, if you look very carefully at the image, you can detect a faint outer ring circling the galaxy with a brightness barely above the background level. This makes the diameter of the whole galaxy structure more than 15 arc-minutes. M 94 is thought to be part of the same group of galaxies that includes M 106. It has a actual diameter of around 56,000 LY, and lies at a distance of around 17 million LY.
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