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 Vaucouleurs.[1] 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.

Messier 83 is an intermediate spiral galaxy of type SABc located in the constellation Hydra.
Diagram of the Hubble - de Vaucouleurs morphological classification system illustrating the class of intermediate spirals.


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"
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"


  1. ^ de Vaucouleurs, Gerard (1963). "Revised Classification of 1500 Bright Galaxies". Astrophysical Journal Supplement. 8: 31. Bibcode:1963ApJS....8...31D. doi:10.1086/190084.