Astronomers using the Wide Field Camera 3 on the NASA/ESA Hubble Space Telescope have captured a new image of the Arches Cluster, the densest known cluster of stars in our Galaxy.
This image of the Arches Cluster of young, massive stars was obtained with the NASA/ESA Hubble Space Telescope. Image credit: NASA / ESA.
Seen toward the constellation Sagittarius, the Arches Cluster is approximately 25,000 light-years from the Solar System.
It is a youngster, about 2 to 2.5 million years old, and lies within a scant 100 light-years of the supermassive black hole believed to lurk in the center of our home Milky Way Galaxy.
Discovered in 1992 as a compact collection of a dozen or so stars, the monster cluster contains thousands of stars, including at least 160 young, very hot stars that are many times larger and more massive than the Sun.
According to astronomers, the Arches Cluster outshines almost every other star cluster in the Milky Way. They estimate that only 1 out of every 10 million stars in our Galaxy is as bright as the stars in the cluster.
With a mass equivalent to more than 10,000 stars like our Sun, the cluster is ten times heavier than typical young star clusters, such as the Orion cluster, scattered throughout the Galaxy.
Despite its brightness the cluster cannot be seen with the naked eye. The visible light from the cluster is completely obscured by gigantic clouds of dust in this region.
To make the cluster visible astronomers have to use detectors which can collect light from the X-ray, infrared, and radio bands, as these wavelengths can pass through the dust clouds.
Recent X-ray observations by the Chandra X-ray Observatory have shown an envelope of 60-million-degree gas around the cluster which is thought to be heated by intense stellar winds from the member stars colliding with the surrounding medium.
