NGC 6231

Open Cluster NGC 6231

(= De Cheseaux No. 9

= Lacaille II.13

= Caldwell 76

= Dunlop 499 = Melotte 153 = Collinder 315), type ‘e’,

in Scorpius

Right Ascension	16 : 54.0 (h:m)
Declination	-41 : 48 (deg:m)
Distance	5.9 (kly)
Visual Brightness	2.6 (mag)
Apparent Dimension	15 (arc min)

NGC 6231 has been one of the discoveries of

Giovanni Batista Hodierna,

published in his 1654 catalog in Palermo, but forgotten until its rediscovery in

the early 1980s. It was independently rediscovered by Philippe Loys De

Cheseaux 1745-46 and by Abbe Lacaille in 1751-52.

This cluster is extremely young, and was estimated only about 3.2 million years

old. Its hottest star is of spectral type O8 and magnitude 4.71, according to the

Sky Catalog 2000. It is approaching us at 22 km/sec.

In John Caldwell’s List

and in the

Astronomical League’s Southern Sky Binocular Club List.

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Hartmut Frommert

([email protected])

Christine Kronberg

([email protected])

Last Modification: 8 Mar 1998, 20:05 MET