Barred Spiral Galaxies
About 1/3 of all spiral galaxies show a bright bar in the nucleus. The classification for a bar in a spiral galaxy is similar to those without the bar, property of the bulge and the extent of the spiral arms. They are designated with a capitol B.
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M91 is an SBb type galaxy. Bars are challenging to explain, dynamically speaking. It has recently been found that our galaxy, the Milky Way, may have a bar as well! Frequently, the ends of the bar lead into normal spiral arms. |
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Perhaps the most interesting barred spiral is M95, classified as an SBb galaxy. Beyond having a very prominent bar, the spiral arms coming from the end of the bar seem more like a ring, and in fact, it is referred to as a typical ringed galaxy. |