New James Webb Space Telescope data is revealing new insights into the Butterfly Nebula, which may explain how rocky planets form from cosmic dust, among other discoveries, as demonstrated in a new paper published in the Monthly Notices of the Royal Astronomical Society.
The focus of the new research was NGC 6303, also known as the Butterfly Nebula, a gathering of minerals and organic material surrounding a hidden star, located roughly 3,400 light-years away in the constellation Scorpius.
Previously imaged by the Hubble Space Telescope before the recent Webb observations, NGC 6302 is one of the most comprehensively studied planetary nebulae in our galaxy, with the new images providing previously unavailable insight into the nebula’s dynamism.
The Structure of Cosmic Dust
“For years, scientists have debated how cosmic dust forms in space,” said lead researcher Dr Mikako Matsuura, of Cardiff University. “But now, with the help of the powerful James Webb Space Telescope, we may finally have a clearer picture.”
Registering at 220,000 Kelvin, the Butterfly Nebula has one of the hottest recorded temperatures of any nebula’s central stars in our galaxy. As such, it forms a powerful engine for the nebula’s brilliant glow and the surrounding torus, a dense band of dust and gas.
Across the cosmos, dust can take on various forms, ranging from random, soot-like atomic structures to perfectly ordered crystalline ones, resembling miniature gems. The James Webb Space Telescope’s latest results show the torus to contain a mix of both types, both crystalline silicates and irregular dust grains, with some dust particles reaching unusually large sizes of one millionth of a meter due to their extended growing period.
“We were able to see both cool gemstones formed in calm, long-lasting zones and fiery grime created in violent, fast-moving parts of space, all within a single object,” Matsuura added. ”This discovery is a big step forward in understanding how the basic materials of planets come together.”
Unusual James Webb Space Telescope Discoveries
Planetary nebulae are among the most beautiful and mysterious structures in the cosmos, although their moniker is a misnomer, since astronomers hundreds of years ago perceived the structures to be round in shape, similar to planets.
Despite this long-standing name, the Butterfly Nebula, as seen in the new James Webb Space Telescope images, offers further proof that many planetary nebulae are not round at all, as NGC 6303’s two lobes resemble the wings of a butterfly. The central band is a donut-shaped torus, which, when viewed from the side due to our vantage point on Earth, gives the impression of a buttery’s central body, hiding the Nebula’s star.
A multilayered emission structure forms outside of the torus, as ions released from atoms and molecules order themselves in accordance with the amount of energy required for their formation. Those with the highest energetic needs congregate nearer to the central star, while those born of lesser energy expand to the perimeter. The researchers identified iron and nickel jets shooting out from the star in opposite directions, forming one of the most noteworthy observations.
Another notable sight was the honeycomb-like shapes formed by carbon-based molecules, which were observed emitting light. The molecules, polycyclic aromatic hydrocarbons, are often found in smoke on Earth. Their location in the nebula suggests that the molecules form when a blast of space wind from the central star impacts the surrounding gas. This is the first time such molecules have been identified forming in an oxygen-rich planetary nebula.
MIRI Observations
Working in integral field unit mode, the MIRI instrument aboard the James Webb Space Telescope captured the recent image, zooming in on the nebula’s center to offer new insights into its complex structure. By combining a camera with a spectrograph, the integral field unit mode allows MIRI to image multiple wavelengths simultaneously.
Such a capability enables scientists to compare how an object’s appearance varies across different wavelengths. For their analysis, the MIRI data were collated with results from the Atacama Large Millimeter/Submillimetre Array.
The team uncovered nearly 200 spectral lines in the James Webb Space Telescope data, providing detailed information on the atoms and molecules present and how they form interconnected structures.
James Webb Space Telescope data also provided the necessary clues to finally determine the central star’s location, obscured by the torus. That star also turned out to be the illumination source for a dust cloud that had previously gone undetected, but shines brilliantly in the mid-infrared wavelengths that MIRI captures.
The new paper, “The JWST/MIRI View of the Planetary Nebula NGC 6302 I.: A UV Irradiated Torus and a Hot Bubble Triggering PAH Formation,” appeared in Monthly Notices of the Royal Astronomical Society on August 27, 2025.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.