The Double Cluster NGC 1850

in the Large Magellanic Cloud

The Double Cluster NGC 1850 in the Large Magellanic Cloud
From The European Southern Observatory
NGC 1850 is a double cluster in the Large Magellanic Cloud, a satellite galaxy of our Milky Way Galaxy, deep in the southern sky. This cluster is representative of young, globular-like stellar associations, that have no counterpart in our own Galaxy. NGC 1850 is peculiar being composed of a main cluster which is about 40 million years old, and a second, smaller, one that is only 4 million years old which is mostly composed of extremely hot stars. About 1000 stars in the main cluster have exploded as supernovae during the past 20 million years. One theory maintains that the birth of the younger cluster was caused by the combined effect of these titanic explosions on the residual gas clouds around the main cluster. They were compressed until they started to form stars and hence a new cluster.
This image is a color a composite of three individual exposures, taken with FORS1 at the VLT UT1 on 3 February 1999, obtained through B (blue), V (green), and Ha (red) filters. The field-of-view is 6.8 arcmin x 6.8 arcmin, corresponding to an area of just over 300 light-years x 300 light-years at the distance of the Large Magellanic Cloud. The exposure times were 60, 60 and 450 seconds and the image quality was 1.0, 0.7 and 0.8 arcsec (FWHM) for the B, V, and Ha frames, respectively. The intensity scale is linear for the B and V images and logarithmic for Ha, to enhance the fine structure of the faintest parts of the nebulosity. North is 33 degrees to the right of the vertical.
There is indeed still much gas around NGC 1850, part of which may well be the remnant of the "parent" gas cloud (i.e. the one from which both clusters were born), the presence of filaments and of various sharp "shocks", e.g. to the left and below NGC 1850, supports the theory of supernova-induced star birth in the younger of the two clusters. That some "protostars" are near or in some of the filaments - is additional evidence for that theory. The nebulosity directly above the main cluster, that is shaped like a "3", is the well-known supernova remnant N57D which may also be associated with NGC 1850.
Based on press release with ESO PR Photo 15/99
Catalog #: Photo 15/99
Target Name: The Double Cluster NGC 1850 in the Large Magellanic Cloud

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 Last Modified On: Sunday, December 17, 2000