Astrophysics (Index)About

OB association

(stellar association with O or B class stars)

An OB association is a stellar association, a loose group of stars of similar spectral class including O-type star and early B-type star stars, i.e., OB stars. It is necessarily a young association because the stars do not last long. After they are all gone, remaining stars will be an ordinary stellar association. An example OB association is the Scorpius-Centaurus Association, which is the nearest to us, about 380-470 light-years, thus of interest for observation.

Further reading:

Referenced by pages:
OB star
rare designator prefixes
stellar association
CTIO Upper-Scorpius OB Association Survey (UScoCTIO)