A stellar nursery is a nebula in which stars are being formed. Enterprise NX-01 charted a stellar nursery in 2151. (ENT: "Cold Front")

A stellar nursery is an interstellar molecular cloud whose density and size permits th formation of molecules, most commonly molecular hydrogen (H2), and eventually stars. Two distinct types, of molecular cloud are known, both associated with star formation: giant molecular clouds (GMCs) and dwarf molecular clouds.

A GMC is huge complex of interstellar gas and dust, composed mostly of molecular hydrogen but also containing many other types of interstellar molecule. GMCs are the coolest (10 to 20 K) and densest (106 to 1010 particles/cm3) portions of the interstellar medium. Stretching typically over 150 light-years and containing several hundred thousand solar masses of material, they are the largest gravitationally bound objects in the Galaxy and, in fact, the largest known objects in the universe made of molecular material.

Dwarf molecular clouds or Bok Gobules are much smaller and denser than GMCs but may still be the scene of star formation. They contain molecular hydrogen (H2), carbon oxides and helium, and around 1% (by mass) of silicate dust. Bok globules most commonly result in the formation of double or multiple star systems