Barred spiral galaxy

A new type, SBm, was subsequently created to describe somewhat irregular barred spirals, such as the Magellanic Clouds, which were once classified as irregular galaxies, but have since been found to contain barred spiral structures.

[2] The creation of the bar is generally thought to be the result of a density wave radiating from the center of the galaxy whose effects reshape the orbits of the inner stars.

This effect builds over time to stars orbiting farther out, which creates a self-perpetuating bar structure.

[10] The bar structure is believed to act as a type of stellar nursery, channeling gas inwards from the spiral arms through orbital resonance, fueling star birth in the vicinity of its center.

[13] Such buckling phenomena are significantly suppressed and delayed by the presence of a supermassive black hole in the galactic center but occur nonetheless.

[15] Recent studies have confirmed the idea that bars are a sign of galaxies reaching full maturity as the "formative years" end.