The Laguna Nebula (Messier 8, NGC 6523) is an interstellar cloud located in the constellation Sagittarius and classified as an emission nebula. This phenomenon emits radiation mainly in the visible red wavelength. It is also known for its black nebulae, or Bok's globules, which are protostellar clouds with diameters of approximately 10,000 AU. Edward Barnard published a catalog of some of the most prominent globules, such as B 88, B 89, and B 296. John Herschel found the Hourglass Nebula, the brightest region of the nebula, which is due to the luminous emission caused by hot young stars, particularly by the star Herschel 36 of magnitude 9.5 and spectral class O7. 9 Sagittarii is the brightest star near the Nebula, having an apparent magnitude of 5.97 and spectral class O5, and ultimately contributing to the nebula's brightness.
The open cluster associated with the nebula, NGC 6530, belongs to class II.2.m.n, according to Robert Julius Trumpler's classification of open clusters, where class I refers to the denser clusters and class IV to the less dense ones; class 1 to agglomerates with little difference in brightness between its components and class 3 to those with a large difference in brightness; and class p for star-poor clusters, m for clusters with the number of stars within the average, and r for star-rich clusters. Despite having a nucleus, the stars belonging to the cluster are very sparse: there are 50 to 100 stars associated with the interstellar cloud of the Laguna nebula. Its brightest star belongs to the spectral class O5 and has an apparent magnitude of 6.9. According to Eichler, the cluster is about 2 million years old and, according to Woldemar Götz, the cluster has an extremely bright class Of star belonging to the spectral class O, but which contains spectral lines of helium and nitrogen.
In 2006, the first four Herbig-Haro objects in the nebula, including object HH 870, the first direct evidence of active star formation by matter accretion.
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