Further to my previous post in this thread, which was an attempt to define what an OB association is, here is an extract from:
Preibisch & Mamajek (2008), in "Handbook of Star Forming Regions, Volume 2 : The Southern Sky", p. 235
(an Astronomical Society of the Pacific monograph)
Their definition of what an OB association is, is somewhat different from the one I arrived at from my reading of some older papers.
Part I :
Part II :
In this paper, they devote
50 pages to the Scorpius-Centaurus OB association (= Sco OB2), which includes
many of the bright stars in Scorpius & Lupus & Crux; this is the nearest region (to the Sun) where lots of
massive and
very luminous and
young stars have recently formed, so it may well be the most popular OB association for current research.
This passage is typical of some of the more descriptive material that is found in the professional scientific literature of astronomy; the main reason why amateurs find it hard to achieve understanding is usually the large amount of specialized jargon and symbolism!!
