NASA's Chandra X-ray telescope has captured a stunning image of Westerlund 1, the largest and closest supergiant star cluster to Earth. This exceptional discovery offers astronomers a unique opportunity to study in detail the formation of stars and the impact of these dense stellar environments on the birth of planets.
Westerlund 1, an unusual star cluster
Located approximately 13,000 light years from Earth, Westerlund 1 is considered relatively close on a cosmic scale. This star cluster, only 3 to 5 million years old, stretches an impressive 7 light years across. To put Westerlund 1's youth into perspective, it is important to note that our middle-aged solar system is approximately 4.6 billion years old.
The mass of Westerlund 1 is equally remarkable, equivalent to that of 100,000 suns. This cluster is one of the rare โsuper star clustersโ still present in the Milky Way, which makes it a particularly interesting subject of study for astronomers.
A look at intensive star formation in the Milky Way
Currently, the Milky Way produces only a few stars per year. However, it was not always this way. About 10 billion years ago, our galaxy experienced a period of intense star formation, giving birth to dozens or even hundreds of stars each year.
Astronomers believe that this intensive star formation was mainly concentrated in super star clusters like Westerlund 1. Studying this exceptional cluster could therefore help to better understand:
Extraordinary stellar density at the heart of Westerlund 1
Chandra data revealed that 1,075 stars are concentrated in a region just 4 light years wide at the center of Westerlund 1. To illustrate this exceptional stellar density, consider that our Sun and its nearest neighboring star , Proxima Centauri, are separated by 4.24 light years.
This concentration of stars at the heart of Westerlund 1 offers astronomers a unique opportunity to study the evolution of stars in an extremely dense environment, very different from that of our solar system.
A halo of hot gas at the center of the cluster
The Chandra image also shows a diffuse pink spot that dominates the center of Westerlund 1. This structure represents a halo of hot gas located at the heart of the cluster. The study of this halo could allow astronomers:
The discovery of this hot gas halo opens new perspectives in the study of super star clusters and their role in the history of our galaxy.
By studying Westerlund 1 in depth, astronomers hope to retrace the history of star formation in the Milky Way and lift the veil on a crucial period in the evolution of our galaxy. This super cluster of stars could thus teach us more about the complex mechanisms that have shaped the Universe as we know it today. Observations by NASA's Chandra Telescope pave the way for exciting new discoveries in astrophysics and promise to revolutionize our understanding of star formation and evolution within galaxies.
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