Unbarred spiral galaxy

Definition

An unbarred spiral galaxy is a type of spiral galaxy that lacks a central bar structure. It features well-defined spiral arms emanating directly from the galactic core.

5 Must Know Facts For Your Next Test

1. Unbarred spiral galaxies are classified as type 'S' in the Hubble sequence.
2. The Milky Way was once thought to be an unbarred spiral but is now classified as a barred spiral.
3. Their spiral arms are often sites of active star formation due to high concentrations of gas and dust.
4. Examples of unbarred spiral galaxies include M31 (Andromeda Galaxy) and M33 (Triangulum Galaxy).
5. Unbarred spirals can have varying bulge sizes, ranging from prominent to nearly absent.

Related terms

Barred Spiral Galaxy:

A type of spiral galaxy with a central bar-shaped structure composed of stars.

Elliptical Galaxy:

A type of galaxy characterized by an ellipsoidal shape and a smooth, nearly featureless light profile.

Spiral Arms:

Regions in a disk-shaped galaxy where stars, gas, and dust are concentrated, often sites of star formation.