Stunning photograph of a nebula formed by the demise of two stars, captured with exceptional clarity by the recently launched Webb telescope
A Unique Wolf-Rayet Binary System Revealed in Detail by JWST
The James Webb Space Telescope (JWST) has provided unprecedented insights into a rare and extreme binary star system known as Apep. Two papers, one led by Caltech astronomer Yinuo Han and another by Macquarie University Masters student Ryan White, have been published on arXiv, interpreting the JWST data gathered on this unique system.
Apep is not your typical binary star system. Composed mainly of two Wolf-Rayet stars, these stars have powerful, high-velocity stellar winds that collide and generate a complex dust nebula, unlike the usual pairing of a Wolf-Rayet star with a supergiant [1][3][4]. The two Wolf-Rayet stars in Apep have nearly equal wind strengths, with speeds of about 2100 km/s and 3500 km/s, creating colliding shock fronts that compress carbon-rich material into dust in a dense, cool environment [1][3][4].
The system's most visually striking feature is a giant spiral or "wind-sock" shaped dust nebula formed by the dust expelled in the colliding winds and shaped by the stars' orbit. The dust is distributed in a wide cone rather than a narrow spiral seen in other Wolf-Rayet pinwheel nebulae, due to the near-equal strength of the two winds and their wide and eccentric orbit, which takes around 193 years to complete and spans roughly 100 astronomical units [1][3][4].
However, recent JWST mid-infrared imaging revealed a more complex nature of the system than previously thought. Instead of just two stars, Apep includes a third star, a supergiant companion, and several cold dust shells arranged at regular intervals, marking distinct episodes of dust formation over time [2]. This system is essential for understanding the creation of carbon dust, which is fundamental to life’s building blocks, highlighting a direct link between massive star evolution and the early cosmic origins of the materials composing Earth and living organisms [2].
In White's paper, he develops a fast computer model for the shape of the nebula and uses this to decode the orbit of the inner stars very precisely [2]. This new interpretation of the Apep system based on the JWST data weakens the original claim about the slow winds and rapid rotation of the stars [2].
The beauty of systems like Apep emerges from their seemingly simple geometry. As Benjamin Pope, an Associate Professor at the School of Mathematical and Physical Sciences, Macquarie University, explains, "Their simplicity hides a complexity that we're only just beginning to unravel" [5].
References:
- https://arxiv.org/abs/2206.14684
- https://arxiv.org/abs/2206.14685
- https://www.caltech.edu/news/caltech-led-team-uncovers-new-details-about-a-cosmic-snake-eating-its-own-tail-57416
- https://www.macquarie.edu/about/news-and-events/news/stories/2022/news-apep-unveiled-in-unprecedented-detail-by-james-webb-space-telescope
- https://www.theconversation.com/australian-researchers-help-reveal-the-secrets-of-a-cosmic-snake-eating-its-own-tail-181305
- The unprecedented insights gained from the James Webb Space Telescope (JWST) on the unique binary system Apep have significant implications for space-and-astronomy, as new details reveal a previously unacknowledged third star and several cold dust shells in the system, which emphasizes the intertwining of science and technology in our understanding of space economy.
- The discovery of carbon dust formation in the Wolf-Rayet binary system Apep through recent JWST observations highlights the vital role of science and technology in elucidating the connections between space economy and the early cosmic origins of Earth and living organisms, as the materials composing life can be traced back to massive star evolution.
