There are two ways in which the morphological types can be written: either the Hubble class (sprials, ellipticals, etc), or as a numeric value between -6 and +11 (de Vaucouleurs). The correspondance between the two scales is detailed in the last column.
The Hubble morphological class is written in Simbad as essentially 2 parts:
The morphology: | ||||
elliptical | E (E0...E9) | -4...-3 | ||
spiral | S (S0, Sa...Sd, Sm) | -2...+9 | ||
barred spiral | SB (SB0, SBa...Sd, SBm) | -2...+9 | ||
irregular | I | +10...+11 | ||
The peculiarities: | (before or after the morphological class) | |||
c | compact | -6(cE), +11 (cI) | ||
d | dwarf | -5(dE) | ||
ringed | r | |||
open spiral | s | |||
peculiar | p |
The colon (:) indicates an uncertainty on the preceding symbol, e.g. S: means probably a Spiral, SB: means a spiral with a probable bar, and S:B: means probably a barred spiral.
In Simbad, two morphological classes may exist, separated by a slash, as E/S0 (elliptical or lenticular).