Coal Sack

Dark nebula in Crux

A huge pocket of very cold, dense gas and dust containing enough matter to make 3 500 Suns.

Other names: Magellan’s Spot, Black Magellanic Cloud, Old Bag of the Night, Black Dove. The Coal Sack is not present in the New General Catalogue (NGC) and in fact does not have an identification number (outside of the Caldwell Catalogue, in which it is C99).

Location: Crux (12 h 31.3 m ,−63° 44.6ʹ)

Angular size: 7° x 5°

Size: 50 light years diameter

Distance: 500 light years

Mass: 3 500 Suns

Highlights:

• It is a dormant stellar nursery, with no stars inside, in the early phases of development into a star-forming region.

• Lies in the Orion (or Local) Arm of the Galaxy (in which the Sun also lies).

• It is the most prominent, isolated dark cloud in the southern Milky Way.

• The Coal Sack is best seen on a dark moonless night when it appears sharply silhouetted against the background Milky Way. Binoculars show tendrils of dark lanes leading southward.

• Forms the head and beak of the Aboriginal “Dark Emu” figure.