The James Webb Space Telescope (JWST) captured a photo of two stars actively producing carbon-rich dust, which may one day fuel the formation of new stars and planets.
Precisely how elements like carbon spread throughout the cosmos remains an area of intense investigation, and thanks to the groundbreaking James Webb Space Telescope, astronomers can learn key insights.
Webb’s latest targets are a pair of stars in Wolf-Rayet 140, about 5,000 light-years away from Earth and in the Milky Way galaxy.
“As the massive stars in Wolf-Rayet 140 swing past one another on their elongated orbits, their winds collide and produce carbon-rich dust,” the Webb Space Telescope team explains. “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.”
Using Webb’s Mid-Infrared Instrument (MIRI), astronomers have observed 17 irregular shells around these stars, although it is possible that “many more” have dissipated into the surrounding space. There is no way to know how long this process will continue, but it could last many thousands of years.
The new photo and associated findings are helping scientists learn more about how carbon forms and is spread throughout the Universe.
“The telescope not only confirmed that these dust shells are real, its data also showed that the dust shells are moving outward at consistent velocities, revealing visible changes over incredibly short periods of time,” says Emma Lieb, the lead author of a new research paper and a doctoral student at the University of Denver in Colorado.
Jennifer Hoffman, a co-author and a professor at the University of Denver, adds that the shell is “racing away from the stars” at speeds greater than 1,600 miles per second, or about 2,600 kilometers per second. This is nearly 1% of the speed of light.
“We are used to thinking about events in space taking place slowly, over millions or billions of years,” Hoffman says. “In this system, [Webb] is showing that the dust shells are expanding from one year to the next.”
The oldest shells visible in the MIRI image are more than 130 years old. Of course, in reality, they are much older and long since dissipated since the objects are 5,000 light-years away. Researchers believe the stars will generate “tens of thousands of dust shells over hundreds of thousands of years.”
“Mid-infrared observations are absolutely crucial for this analysis, since the dust in this system is fairly cool. Near-infrared and visible light would only show the shells that are closest to the star,” adds Ryan Lau, a co-author and astronomer at NSF NOIRLab in Tuscon, Arizona. Lau led early research on this system in 2022. “With these incredible new details, the telescope is also allowing us to study exactly when the stars are forming dust — almost to the day.”
The observed Wolf-Rayet star is in the latter stages of its life. 10 times more massive than the Sun, the star will either explode or collapse into a black hole. Scientists are hoping for the latter scenario because the dust shells should survive the event.
“A major question in astronomy is, where does all the dust in the universe come from?” Lau explains. “If carbon-rich dust like this survives, it could help us begin to answer that question.”
The new results have been published in the Astrophysical Journal Letters.
Image credits: Image: NASA, ESA, CSA, STScI, Science: Emma Lieb (University of Denver), Ryan Lau (NSF’s NOIRLab), Jennifer Hoffman (University of Denver)