A section of the Ara OB1 Stellar Association. Photo: ESO/PA WireA celestial ‘treasure trove’ has been uncovered in new images from the southern constellation of Ara, the Altar.
Star clusters, glowing nebulae and active star-forming regions are all present in a region known as the Ara OB1 Association some 4,000 light years from earth.
The image here, the most detailed view of this part of the sky so far, was taken using the VLT Survey Telescope at the European Southern Observatory’s Paranal observatory in Chile.
At the centre is the open star cluster NGC 6193 containing around 30 bright stars and forming the heart of the Ara OB1 Association. The two brightest stars, hot giants, together provide the main illumination source for the nearby emission nebula, the Rim Nebula, visible to the right of the cluster.
A stellar association is a large grouping of loosely bound stars that have not yet completely drifted away from their initial formation site.
OB associations consist largely of very young blue-white stars, which are about 100,000 times brighter than the sun and 10 to 50 times more massive.
The spectacular image was created from more than 500 individual pictures taken through four different colour filters with a total exposure time of more than 56 hours.