An unbarred spiral galaxyAstronomy Pictures

(accessed 18 April 2010) is a type of spiral galaxy without a central bar, or one that is not a

barred spiral galaxy A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about two thirds of all spiral galaxies, and generally affect both the motions of stars and interstellar gas within spiral galaxies ...

. It is designated with an SA in the

galaxy morphological classification Galaxy morphological classification is a system used by astronomers to divide galaxies into groups based on their visual appearance. There are several schemes in use by which galaxies can be classified according to their morphologies, the most f ...

scheme. Barless spiral galaxies are one of three general types of spiral galaxies under the ''de Vaucouleurs system'' classification system, the other two being

intermediate spiral galaxy An intermediate spiral galaxy is a galaxy that is in between the classifications of a barred spiral galaxy and an unbarred spiral galaxy. It is designated as SAB in the galaxy morphological classification system devised by Gerard de Vaucouleu ...

and barred spiral galaxy. Under the ''Hubble tuning fork'', it is one of two general types of spiral galaxy, the other being barred spirals.

Grades

Unbarred lenticular galaxy

An unbarred lenticular galaxy is a lenticular version of an unbarred spiral galaxy. They have the Hubble type of SA0. An example of this is the galaxy, AM 0644-741. For other examples see :Unbarred lenticular galaxies.

References

* Galaxy morphological types {{Spiral-galaxy-stub