An Etymological Dictionary of Astronomy and Astrophysics

An opaque region of a → molecular cloud (A_V  10 mag) which is considered to be the progenitor of → star formation.
Dense cores have temperatures of about 10 K and masses of roughly 1 to 10Msun each and in which the → molecular hydrogen density is roughly 10⁴-10⁵ cm^-3 and size 0.1 pc. The → self-gravity of a dense core plays a central part in star formation. See also → hot molecular core.

See also: → dense; → core.