A 70-minute image of the “open” star cluster M6 in the constellation Scorpius. This cluster lies along the galactic equator on the celestial sphere, near the center of our Milky Way galaxy. As a result, the background reveals a rich concentration of countless stars due to the much greater density of stars along the plane of the galaxy. However, the cluster is only 1,600 light years from Earth, far short of the actual center of our galaxy some 25,000 light years away. So, while M6 appears to be embedded in the core of our galaxy, it is in fact more than 20,000 light years away.
M6 contains about 80 stars spread over an area 12 light years wide. Most of the stars are “B class” blue giants, as clearly seen in this image. However, the brightest star in the cluster is the anomalous reddish star. This is BM Scorpii, a “K class” red-giant star millions of times larger than our Sun. Its reddish color is due to its low surface temperature resulting from the prodigious expansion of the star in the red-giant stage.
M6 is often called the “Butterfly Cluster,” owing to what some perceive to be its butterfly shape.
The Butterfly Cluster (M6) in Scorpius
Date Taken:June 20, 2015
Location Taken:Siding Spring Observatory, NSW Australia
Conditions of Location: Equipment Used:Planewave 20" corrected Dall-Kirkham telescope, FLI PL09000 camera
Processing Used:9 x 3 minutes luminance, 7 x 2 minutes RGB, for a total exposure of 70 minutes
Distance from Location:1,600 light years
Constellation:Scorpius
Other Link: