NASA’s James Webb Space Telescope (JWST) has captured the super bright, massive Wolf-Rayet Star WR 124 in unprecedented detail on the cusp of going supernova. The star could give astronomers new insights into the beginnings of other celestial objects. In the turbulent nebula surrounding such stars, cosmic dust forms. This cosmic dust is made of the heavy-element building blocks of the modern Universe, including life on Earth.
What are Wolf-Rayet Stars?
Wolf-Rayet stars are a type of massive stars that are in an advanced stage of stellar evolution and exhibit very high rates of mass loss. These stars are typically more massive than 25 times the mass of the Sun and have short lifetimes, making them rare objects in the universe. While we have identified around 220 Wolf-Rayet stars in our Milky Way galaxy, it is estimated that there could be between 1,000 to 2,000 such stars in our galaxy, with the majority being obscured by dust.
Wolf Rayet Phase:
These massive stars have very short lifecycles, and only a small fraction of them undergo a brief but important phase known as the Wolf-Rayet phase before they ultimately go supernova. The Wolf-Rayet phase is characterized by the star shedding its outer layers, which leads to the formation of halos of gas and dust around the star.
WR 124 and why Astronomers care:
WR 124 is a massive star that has already lost 10 times the mass of the Sun, and it’s still losing more. As the star continues to shed its outer layers, the expelled gas moves away from the star, eventually cooling and forming cosmic dust particles.
These particles emit infrared light, which can be detected by the James Webb Space Telescope. By observing these infrared emissions from the dust, Webb will provide astronomers with valuable information about the properties and distribution of the dust in the vicinity of WR 124, shedding light on the star’s evolutionary history and the processes that drive its mass loss. Webb’s detailed observations of this rare phase are highly valuable to astronomers as they offer crucial insights into the evolution of massive stars and the processes that lead to their explosive deaths.
Exploring Cosmic Dust with Webb’s Cosmic Dust Studies:
The James Webb Space Telescope allows scientists to study cosmic dust in new ways. This dust can be seen best with infrared light, which Webb can detect. Webb’s cameras balance the brightness of the star’s core with the fainter surrounding gas, making it easier to see the knotty details.
The telescope’s Mid-Infrared Instrument (MIRI) shows the clumpy structure of the gas and dust nebula formed by the material the star has expelled. Overall, Webb gives us a better understanding of how the dust and gas are distributed around the star and how it’s losing its mass.
Prior to the James Webb Space Telescope, scientists lacked sufficient detailed data to study the production of dust in environments like WR 124. They were unable to determine if the dust grains were large enough to survive a supernova and contribute significantly to the overall dust budget of the universe. With Webb’s advanced capabilities, these questions can now be investigated with real data, enabling astronomers to gain a better understanding of cosmic dust production.
Cosmic Dust, Their importance and the Universe’s Dust Budget:
Astronomers are interested in the origin of cosmic dust as it contributes to the formation of stars, planets, and life on Earth. However, current theories cannot explain the abundance of dust in the universe. There is more dust than expected, and this dust budget surplus is a mystery that scientists hope to solve with new observations.
In addition to studying the production of cosmic dust, stars like WR 124 also serve as a valuable tool for understanding the early universe. These dying stars were responsible for the creation of heavy elements, including those found on Earth, in their cores.
These elements were then dispersed throughout the universe during supernova explosions, seeding the cosmos with the raw materials necessary for the formation of future generations of stars, planets, and potentially even life. Studying the behaviour of stars like WR 124, scientists can gain insight into the processes that contributed to the formation and evolution of the early universe.
The James Webb Space Telescope’s detailed image of WR 124 captures a fleeting moment of transformation and offers the promise of uncovering cosmic dust’s long-shrouded mysteries. As the world’s premier space science observatory, Webb will continue to investigate the mysteries of our solar system, study distant worlds around other stars, and explore the origins of our universe. The international program, led by NASA, includes partners such as ESA (European Space Agency) and CSA (Canadian Space Agency).