NGC 6530

Open Cluster NGC 6530

(= Collinder 362),

type ‘e’,

in Sagittarius

Right Ascension	18 : 04.8 (h:m)
Declination	-24 : 20 (deg:m)
Distance	5.2 (kly)
Visual Brightness	4.6 (mag)
Apparent Dimension	14 (arc min)

NGC 6530 is an extremely young open cluster which was formed from the material

of the Lagoon Nebula M8, and it is situated well

within this diffuse nebula.

This cluster was apparently first observed by

Hodierna before 1654, and independently

found by Flamsteed in 1680, who cataloged it as his No. 2446.

NGC 6530 was classified as of Trumpler type “II 2 m n” (see e.g. the

Sky Catalog 2000), meaning that it is detached but only weakly

concentrated toward its center, its stars scatter in a moderate range of

brightness, it is moderately rich (50–100 stars), and associated with nebulosity

(certainly, with the Lagoon nebula). As the light of its member stars show

little reddening by interstellar matter, this cluster is probably situated just

in front of the Lagoon Nebula. Its brightest star is a 6.9 mag hot O5 star, and

Eichler gives its age as 2 million years. Woldemar Götz mentions this

cluster as containing one peculiar Of star, an extremely hot bright star of

spectral type O with peculiar spectral lines of ionized Helium and Nitrogene.

Our image was cropped from a larger Lagoon Nebula image by

Tim Puckett.

NGC 6530 can be glimpsed in many images of the

Lagoon Nebula M8.

---

Hartmut Frommert

([email protected])

Christine Kronberg

([email protected])

Last Modification: 29 Mar 1998, 12:30 MET