SBa galaxy

An SBa galaxy is a type of barred spiral galaxy, characterized by a bright, relatively large nuclear bulge and tightly wound spiral arms that emerge from the ends of a central bar or a circular ring. These arms are generally smooth in appearance.1

Spiral galaxies, including barred spirals, are classified based on their visual appearance, a system initially developed by Edwin Hubble and later revised by Allan Sandage. They possess a nucleus surrounded by a disk and spiral structure. The arms and disk of spiral galaxies appear blue, while their central areas are red. SBa galaxies are a subclassification (the 'a' indicating a large nucleus and tightly coiled arms) within the broader category of barred spirals (SB). The Andromeda Galaxy is a well-known example of an Sb galaxy, though not specifically SBa.12