Coal sack

from Wikipedia, the free encyclopedia
Dark fog
Coal sack
Coalsack-ESO-B06.jpg
In the middle the Kohlensack dark nebula, above it on the right the Southern Cross in a photo from the European Southern Observatory .
Constellation southern Cross
Position
equinox : J2000.0
Right ascension 12h 50m
declination -62 ° 30 ′
Further data
Angular expansion

5 ° × 7 °

distance

500–600 ly

diameter 30 × 35 ly
history
Catalog names
Aladin previewer
Constellations Crux and Centaurus (southern part), in between the coal sack

The Coal Sack is one of the most famous dark clouds in the sky and, along with Horsehead Nebula , Cone Nebula and others, it is also one of the few objects of its kind with a proper name. The coal sack stands in the middle of the southern Milky Way , between the constellations Crux (Southern Cross), the centaur surrounding it and the fly (Musca). It is 500 to 600 light years away and forms a noticeable “hole” in the surrounding, very star-rich area. Well-known objects at "binoculars" are the Carina Nebula and the Open Star Cluster NGC 4755 , which John Herschel called the jewel box .

The Aborigines in Australia know the series of dark clouds from the constellation Schild in the north down to the Coal Sack also as the Emu - with the Coal Sack as a head.

The astronomer Kalevi Mattila was able to determine in 1970 that the dark nebula is not completely black, but rather shines very weakly (about 10% of the light of the Milky Way behind it ). This is caused by the light reflex of the darkened stars behind it.

Trivia

The mist also plays a central role in the novel The Shard in the Eye of God by Larry Niven and Jerry Pournelle .

Web links

Individual evidence

  1. ^ Kalevi Mattila : Interpretation of the surface brightness of dark nebulae . In: Astronomy & Astrophysics . tape 9 , 1970, ISSN  0004-6361 , pp. 53–63 , bibcode : 1970A & A ..... 9 ... 53M (English).