How Binary Star Orbits Build Carbon Shells: Wolf-Rayet 140 Visualization | Webb
Astronomers using the NASA/European Space Agency/Canadian Space Agency James Webb Space Telescope have identified two stars responsible for generating carbon-rich dust a mere 5,000 light-years away in our own Milky Way galaxy. As the massive stars in Wolf-Rayet 140 swing past one another on their elongated orbits, their winds collide and produce the carbon-rich dust. For a few months every eight years, the stars form a new shell of dust that expands outward—and may eventually go on to become part of stars that form elsewhere in our galaxy.
Astronomers have long tried to track down how elements like carbon that are essential for life. It has become widely distributed across the Universe. Now, the James Webb Space Telescope has examined one ongoing source of carbon-rich dust in our own Milky Way galaxy in greater detail: Wolf-Rayet 140—a system of two massive stars that follow a tight, elongated orbit.
As they swing past one another (within the central white dot in the Webb images), the stellar winds from each star slam together, the material compresses, and carbon-rich dust forms. Webb’s latest observations show 17 dust shells shining in mid-infrared light that are expanding at regular intervals into the surrounding space.
“The telescope confirmed that these dust shells are real, and its data also showed that the dust shells are moving outward at consistent velocities, revealing visible changes over incredibly short periods of time,” said Emma Lieb, the lead author of the new paper and a doctoral student at the University of Denver in Colorado.
Every shell is racing away from the stars at more than 2,600 kilometres per second, almost 1% the speed of light. “We are used to thinking about events in space taking place slowly, over millions or billions of years,” added Jennifer Hoffman, a co-author and a professor at the University of Denver. “In this system, the observatory is showing that the dust shells are expanding from one year to the next.”
“Seeing the real-time movement of these shells between Webb’s observations that were taken only 13 months apart is truly remarkable,” said Olivia Jones, a co-author at the UK Astronomy Technology Centre, Edinburgh. “These new results are giving us a first glimpse of the potential role of such massive binaries as factories of dust in the Universe.”
Like clockwork, the stars’ winds generate dust for several months every eight years, as the pair make their closest approach during a wide, elongated orbit. Webb also shows where dust formation stops.
Duration: 12 seconds
Release Date: January 13, 2025
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