SIMBAD: Morphological type coding


Simbad Help   ⋅   Top   ⋅   Previous   ⋅   Next

Chapter E. Morphological type coding

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).


Simbad Help   ⋅   Top   ⋅   Previous   ⋅   Next