Editing Stellar association (section)

===T associations===
Young stellar groups can contain a number of infant [[T Tauri star|T Tauri]] stars that are still in the process of entering the [[main sequence]]. These sparse populations of up to a thousand T Tauri stars are known as ''T associations''. The nearest example is the [[Taurus-Auriga T association]] (Tau-Aur T association), located at a distance of 140 [[parsec]]s from the Sun.<ref>{{cite journal
 |author1=Frink, S. |author2=Roeser, S. |author3=Neuhaeuser, R. |author4=Sterzik, M. K.
 | title=New proper motions of pre-main sequence stars in Taurus-Auriga
 | journal=Astronomy and Astrophysics | year=1999
 | volume=325 | pages=613–622
 | url=http://www.ari.uni-heidelberg.de/publikationen/pap1997/1997021/1997021.htm |bibcode=1997A&A...325..613F |arxiv=astro-ph/9704281 }}</ref> Other examples of T associations include the [[R Corona Australis T association]], the [[Lupus T association]],  the [[Chamaeleon T association]] and the [[Velorum T association]]. T associations are often found in the vicinity of the molecular cloud from which they formed. Some, but not all, include O-B class stars. To summarize the characteristics of Moving groups members: they have the same age and origin, the same chemical composition and they have the same amplitude and direction in their vector of velocity.