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, it will be a "non-OB" stellar association.

An example is the Scorpius-Centaurus Association, which is the nearest to us, about 380-470 light-years, thus of interest for observation.


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