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 Vaucouleurs, and is also known as a weakly barred spiral galaxy. Subtypes are labeled as SAB0, SABa, SABb, or SABc, following a sequence analogous to the Hubble sequence for barred and unbarred spirals. The subtype (0, a, b, or c) is based on the relative prominence of the central bulge and how tightly wound the spiral arms are.
Examples
Example Type Image Information Notes SAB0- SAB0- is a type of lenticular galaxy SAB0 SAB0 is a type of lenticular galaxy SAB0+ SAB0+ is a type of lenticular galaxy SAB0/a SAB0/a can also be considered a type of intermediate lenticular galaxy Messier 65 SABa M65 is an "SAB(rs)a" NGC 4725 SABab NGC 4725 is an "SAB(r)ab pec" Messier 66 SABb M66 is an "SAB(s)b" Messier 106 SABbc M106 is an "SAB(s)bc" Sculptor Galaxy SABc Sculptor is an "SAB(s)c" NGC 2403 SABcd NGC 2403 is an "SAB(s)cd" SABd SABdm SABdm can also be considered a type of intermediate Magellanic spiral NGC 4625 SABm SABm is a type of Magellanic spiral (Sm) NGC 4625 is an "SAB(rs)m pec" Fireworks Galaxy SAB(rs)cd NGC 4625 is an "SAB(rs)cd"
References