SIMBAD: Object Classification in SIMBAD


Simbad Help   ⋅   Top   ⋅   Previous   ⋅   Next

|In a few months the historical list of object types below will be replaced by a reorganized list, based on physical properties, and on the evolutionary state for stars. It will allow a more interactive search, and will provide minimal definitions. The hierarchies between object types will evolve: for instance, a RR Lyrae Star will still be in the hierarchy of Variable Stars, and also in the hierarchy of Horizontal Branch Stars. If you are using the hierarchies in scripts, you might have to adapt your scripts to the new description.


(Last revision of the classification: 14-Oct-2021)

The Object Type in Simbad is defined as a hierarchical classification: a numeric type is made of up to four levels corresponding to classes detailed below.

A presentation of the system can be found in the paper by F. Ochsenbein and P. Dubois in 'Astronomy from Large Databases II:' ed. A. Heck & F. Murtagh, 1992, pp 405-410

Note that Simbad emphasizes the physical nature of the object rather than a peculiar emission in some region of the electromagnetic spectrum or the location in peculiar clusters or external galaxies. Therefore objects are classified as peculiar emitters (classes 01. to 07.) only if nothing more about the nature of the object is known, i.e. it cannot be decided whether the object is a star, a multiple system, a nebula or a galaxy.

We would appreciate your comments or suggestion, e.g. by e-mail to

Each class has normally a standard designation, a condensed one (used in tables) and an extended explanation.

Please see list of otypes : here



Simbad Help   ⋅   Top   ⋅   Previous   ⋅   Next