Webb Reveals the Secrets of the Butterfly Nebula (NGC 6302)
The James Webb Space Telescope (NASA/ESA/CSA) has delivered a groundbreaking image and data of the Butterfly Nebula (NGC 6302), a cosmic jewel located about 3,400 light-years away in the constellation Scorpius. Behind its spectacular “wings” of glowing gas, Webb has pierced the mysteries of its heart, revealing a blazing central star, a dusty torus, and unexpected interstellar chemistry.
A cosmic butterfly with wings of gas
The Butterfly Nebula is a planetary nebula, a misleading name since it is not a planet but the final breath of a Sun-like star. When such stars reach the end of their lives, they expel their outer layers, forming clouds of astonishing shapes, illuminated by the ultraviolet radiation from their core.
Already observed by Hubble, NGC 6302 now reveals through Webb an unprecedented level of complexity: its two luminous lobes stretch out like wings, while a dense dusty core concentrates the most fascinating phenomena.
This image set showcases three views of the Butterfly Nebula, also called NGC 6302. The Butterfly Nebula, located about 3400 light-years away in the constellation Scorpius, is one of the best-studied planetary nebulae in our galaxy. Planetary nebulae are among the most beautiful and most elusive creatures in the cosmic zoo. These nebulae form when stars with masses between about 0.8 and 8 times the mass of the Sun shed most of their mass at the end of their lives. The planetary nebula phase is fleeting, lasting only about 20 000 years. The Butterfly Nebula is a bipolar nebula, meaning that it has two lobes that spread in opposite directions, forming the ‘wings’ of the butterfly. A dark band of dusty gas poses as the butterfly’s ‘body’. This band is actually a doughnut-shaped torus that’s being viewed from the side, hiding the nebula’s central star – the ancient core of a Sun-like star that energises the nebula and causes it to glow. The dusty doughnut may be responsible for the nebula’s insectoid shape by preventing gas from flowing outward from the star equally in all directions. The first and second of the three images shown here highlight the bipolar nature of the Butterfly Nebula in optical and near-infrared light captured by the NASA/ESA Hubble Space Telescope. The new Webb image on the right zooms in on the centre of the Butterfly Nebula and its dusty torus, providing an unprecedented view of its complex structure. The Webb data are supplemented with data from the Atacama Large Millimetre/submillimetre Array, a powerful network of radio dishes. While the nebula’s central star is blanketed with thick, dusty gas at optical wavelengths, Webb’s infrared capabilities reveal the central star and show the doughnut-shaped torus and interconnected bubbles of dusty gas that surround it. [Image description: Three views of the same nebula, presented side by side. The left and middle images, which are labeled ‘Hubble Optical’ and ‘Hubble Near. Credit: ESA/Webb, NASA & CSA, M. Matsuura, J. Kastner, K. Noll, ALMA (ESO/NAOJ/NRAO), N. Hirano, J. Kastner, M. Zamani (ESA/Webb)
An Extreme Central Star
Thanks to the infrared vision of MIRI (Mid-InfraRed Instrument), Webb has finally been able to pinpoint the central star, long hidden from view. The verdict: a blazing furnace at 220,000 K, making it one of the hottest stars ever known at the heart of a planetary nebula. This extreme radiation sculpts the surrounding gas, ionizes elements, and powers the opposing jets that give the nebula its symmetry.
This image takes the viewer on a deep dive into the heart of the Butterfly Nebula, NGC 6302. The Butterfly Nebula, located about 3400 light-years away in the constellation Scorpius, is one of the best-studied planetary nebulae in our galaxy. Planetary nebulae are among the most beautiful and most elusive creatures in the cosmic zoo. These nebulae form when stars with masses between about 0.8 and 8 times the mass of the Sun shed most of their mass at the end of their lives. The planetary nebula phase is fleeting, lasting only about 20 000 years. At the centre of the Butterfly Nebula is the ancient core of a Sun-like star that energises the surrounding nebula and causes it to glow. This scorching central star is hidden from view at optical wavelengths, but Webb’s infrared capabilities have revealed the star and its surroundings in great detail. This image, which combines infrared data from the NASA/ESA/CSA James Webb Space Telescope with submillimetre observations from the Atacama Large Millimetre/submillimetre Array (ALMA), shows the doughnut-shaped torus and interconnected bubbles of dusty gas that surround the nebula’s central star. The torus is oriented vertically and nearly edge-on from our perspective, and it intersects with bubbles of gas enclosing the star. The bubbles appear bright red in this image, illuminated by the light from helium and neon gas. Outside the bubbles, jets traced by emission from ionised iron shoot off in opposite directions. These features are labeled in an annotated version of this image. [Image description: The complicated structure at the centre of the Butterfly Nebula, NGC 6302. There is a bright source at the centre that is surrounded by greenish nebulosity and several looping lines in cream, orange and pink. One of these lines appears to form a ring oriented vertically and nearly edge-on around the bright source at the centre. Other lines trace out a figure eight shape. Moving outward from these complex lines and green nebulosit. Credit: ESA/Webb, NASA & CSA, M. Matsuura, ALMA (ESO/NAOJ/NRAO), N. Hirano, M. Zamani (ESA/Webb)
The Dust Torus and Its Crystals
At the center, a dust torus encircles the star. Webb revealed that it is composed of crystalline silicates (similar to terrestrial quartz) and irregular grains about one micron in size. These crystals bear witness to a long growth process and a gradual enrichment in heavy elements. This dust, blown into space, may one day mix with other cosmic clouds and contribute to the birth of new planets.
A Surprising Chemistry: Hydrocarbons in an Oxygen-Rich World
The most unexpected discovery is that of complex carbon-based molecules—polycyclic aromatic hydrocarbons (PAHs). Usually found in carbon-rich environments, they appear here in a nebula dominated by oxygen.
These PAHs, with hexagonal structures reminiscent of honeycomb cells, likely formed when the star’s expanding wind bubble violently collided with the surrounding gas. This is a scientific first that challenges current models of interstellar chemistry.
An Unmatched Spectral Mapping Webb recorded nearly 200 different spectral lines, providing a chemical and energetic map of the nebula:
highly energetic ions near the center,
calmer ions at the periphery,
jets traced by ionized iron and nickel.
This stratification sheds light on the evolutionary mechanisms of a dying star and the complex interactions between gas and dust.
This image set showcases three views of the Butterfly Nebula, also called NGC 6302. The Butterfly Nebula, located about 3400 light-years away in the constellation Scorpius, is one of the best-studied planetary nebulae in our galaxy. Planetary nebulae are among the most beautiful and most elusive creatures in the cosmic zoo. These nebulae form when stars with masses between about 0.8 and 8 times the mass of the Sun shed most of their mass at the end of their lives. The planetary nebula phase is fleeting, lasting only about 20 000 years. The Butterfly Nebula is a bipolar nebula, meaning that it has two lobes that spread in opposite directions, forming the ‘wings’ of the butterfly. A dark band of dusty gas poses as the butterfly’s ‘body’. This band is actually a doughnut-shaped torus that’s being viewed from the side, hiding the nebula’s central star – the ancient core of a Sun-like star that energises the nebula and causes it to glow. The dusty doughnut may be responsible for the nebula’s insectoid shape by preventing gas from flowing outward from the star equally in all directions. The lower two images of the three images shown here highlight the bipolar nature of the Butterfly Nebula in optical and near-infrared light captured by the NASA/ESA Hubble Space Telescope. The upper image zooms in on the centre of the Butterfly Nebula and its dusty torus, providing an unprecedented view of its complex structure. The Webb data are supplemented with data from the Atacama Large Millimetre/submillimetre Array, a powerful network of radio dishes. While the nebula’s central star is blanketed with thick, dusty gas at optical wavelengths, Webb’s infrared capabilities reveal the central star and show the doughnut-shaped torus and interconnected bubbles of dusty gas that surround it. [Image description: Three views of the same nebula, presented in a triangle with one image on top and two on the bottom. The bottom two images, which are labeled ‘Hubble Opti. Credit: ESA/Webb, NASA & CSA, M. Matsuura, J. Kastner, K. Noll, ALMA (ESO/NAOJ/NRAO), N. Hirano, J. Kastner, M. Zamani (ESA/Webb)
Why It Matters
Understanding the Sun’s future: In a few billion years, our star will meet the same fate.
Studying the formation of complex molecules in space, which may have an indirect connection to the emergence of life.
Testing stellar and chemical evolution models through unprecedented mapping.
Source
Find the article published on the ESA Webb website on 08/27/2025 here.
