NASA’s James Webb Space Telescope (JWST) has captured a stunning image of Westerlund 1, the largest remaining super star cluster in the Milky Way, revealing a dense collection of massive stars located 12,000 light-years from Earth. Using its Near-Infrared Camera (NIRCam), Webb was able to peer through the dust and gas surrounding the cluster, providing astronomers with unprecedented detail of its stellar population.
NASA’s Webb Captures Stunning View of Westerlund 1, The Milky Way’s Largest Star Cluster
By Lydia Amazouz
Published on October 10, 2024 09:25
The James Webb Space Telescope (JWST) has captured a breathtaking image of Westerlund 1, the largest super star cluster in the Milky Way, offering astronomers new insights into the formation and evolution of massive stars.
Using the telescope’s Near-Infrared Camera (NIRCam), researchers were able to see through the dense gas and dust surrounding the cluster, revealing a population of stars up to 100,000 times the mass of the Sun. The study, conducted by a team led by Amy Simon of NASA’s Goddard Space Flight Center, was published as part of the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS), which aims to better understand star formation. The findings, which were published in The Astrophysical Journal, highlight the future of Westerlund 1, where over 1,500 stars are expected to explode as supernovae in the next 40 million years.
The Immense Scale of Westerlund 1
Westerlund 1 is a relatively young super star cluster, estimated to be between 3.5 and 5 million years old—young in astronomical terms. It contains between 50,000 and 100,000 times the mass of the Sun and spans a region about six light-years across. The cluster’s stars include some of the most massive and luminous objects known, such as yellow hypergiants, which can shine a million times brighter than our Sun.
Astronomers have long been interested in studying Westerlund 1, not only because of its massive size but also due to the unique insights it can provide into the life cycles of massive stars. These stars, which burn through their fuel at an astonishing rate, have relatively short lifespans compared to smaller stars like the Sun.
Why Westerlund 1 is A Crucial Target for Webb
The JWST’s ability to capture infrared light allows it to peer through the dense clouds of gas and dust that obscure much of Westerlund 1 in visible light. This capability is crucial for studying star clusters like this one, which are often hidden behind interstellar material.
Thanks to Webb's imaging, astronomers have been able to catalog the different types of stars within Westerlund 1, ranging from red supergiants and luminous blue variables to more exotic stars like magnetars and X-ray pulsars. These diverse stellar populations help researchers better understand the dynamics of such massive clusters and provide a clearer picture of the initial mass function, which describes how stars of different masses form and evolve within the same cluster.
A Future Filled with Supernovae
The stars in Westerlund 1 may be young, but many of them are already nearing the end of their lives. Massive stars like those found in this cluster tend to have lifetimes of only a few million years before they explode as supernovae. Over the next 40 million years, astronomers predict that Westerlund 1 will experience more than 1,500 supernovae, providing a spectacular display of stellar death.
Astronomers are particularly excited about the prospect of observing these future supernovae, as the resulting explosions will scatter heavy elements across space, contributing to the formation of new stars and potentially even planetary systems. The dense environment of Westerlund 1 makes it an ideal laboratory for studying these processes, helping to shed light on how supernovae influence star formation in dense stellar nurseries.
A Laboratory for Understanding Massive Stars
Westerlund 1 is not just a snapshot of the Milky Way’s past star formation but also a crucial laboratory for studying the evolution of massive stars. Astronomers believe that super star clusters like this one were more common during the early history of the galaxy when star formation rates were much higher. Understanding clusters like Westerlund 1 can therefore provide valuable clues about how the Milky Way evolved and what conditions were like during its most active periods of star formation.
Moreover, studying massive clusters like Westerlund 1 can help astronomers draw parallels with similar clusters in other galaxies, contributing to a broader understanding of star formation across the universe. Webb’s detailed observations of Westerlund 1 and other open star clusters will continue to shape our understanding of the life cycles of stars, from their formation in dense clusters to their dramatic deaths as supernovae.
A Glimpse into The Future
The James Webb Space Telescope has once again proven its value in advancing our knowledge of the cosmos, providing astronomers with an unprecedented look at one of the Milky Way’s most massive star clusters. Westerlund 1, with its dense population of massive stars and potential for future supernovae, offers a unique opportunity to study the evolution of stars on a grand scale. As Webb continues to observe this cluster, scientists will gain deeper insights into the processes that shape not only individual stars but also entire galaxies.
In the decades to come, Westerlund 1 will remain a focal point for research, as its stars undergo their final stages of evolution, culminating in a series of spectacular supernova explosions. Through the lens of the James Webb Space Telescope, we are witnessing the unfolding story of one of the most extraordinary star-forming regions in our galaxy.