NASA and ESA’s Hubble Space Telescope has peered into a fascinating cluster of stars located towards the center of our Milky Way. Known as the Quintuplet Cluster, this region had been hard to observe until now, owing to its position just 100 light-years from the center of the galaxy, 25,000 light-years from Earth.
But NASA and ESA decided to train the super-powerful Hubble on this intriguing region, one of the brightest clusters in the galaxy, capturing the clearest view of it yet. So close is it to the center of the galaxy that it cannot be seen in visible light; instead, the image you’re seeing above was taken in infrared.
The cluster gets its name from its five brightest stars, but as you can see in the image they are almost impossible to spot among the hundreds of other stars Hubble was able to image in the cluster. Two of these are extremely rare stars known as luminous blue variables, named the Pistol Star and V4650 Sgr.
To find the Pistol Star, NASA says you need to draw a line horizontally through the center of the image, and it will be found “hovering just above the line about one third of the way along it.” One of the most luminous stars in the Milky Way, the Pistol Star resides inside the unseen Pistol Nebula and will explode as a supernova or a hypernova, the most powerful type of supernova, in one to three million years.
Elsewhere in the cluster are several red supergiants, some of the largest stars in the galaxy, which burn their fuel quickly. This gives them a short lifespan and allows astronomers to estimate the age of the cluster at about four million years. When they explode, the energy they release will heat the surrounding material in the cluster.
The cluster is said to have a mass of more than 10,000 solar masses, and is also 10 times larger than other typical young star clusters seen elsewhere in the galaxy. Unfortunately for the cluster, it will likely be ripped apart by gravitational tidal forces from the galaxy’s core in a few million years, although this likely won’t stop stars like the Pistol Star from exploding.
Owing to its proximity to the center of our galaxy, located near the Arches Cluster, the Quintuplet Cluster was not discovered until 1990. But now, thanks to Hubble, we can start to understand more about some fascinating regions like this at the heart of the Milky Way.