This blazing stellar engine is responsible for the nebula’s gorgeous glow, but its full power may be channelled by the dense band of dusty gas that surrounds it: the torus. The new Webb data show that the torus is composed of crystalline silicates like quartz as well as irregularly shaped dust grains. The dust grains have sizes on the order of a millionth of a metre – large, as far as cosmic dust is considered – indicating that they have been growing for a long time.

Outside the torus, the emission from different atoms and molecules takes on a multilayered structure. The ions that require the largest amount of energy to form are concentrated close to the centre, while those that require less energy are found farther from the central star. Iron and nickel are particularly interesting, tracing a pair of jets that blast outward from the star in opposite directions.

Intriguingly, the team also spotted light emitted by carbon-based molecules known as polycyclic aromatic hydrocarbons, or PAHs. They form flat, ring-like structures, much like the honeycomb shapes found in beehives. On Earth, we often find PAHs in smoke from campfires, car exhaust, or burnt toast. Given the location of the PAHs, the research team suspects that these molecules form when a ‘bubble’ of wind from the central star bursts into the gas that surrounds it. This may be the first-ever evidence of PAHs forming in a oxygen-rich planetary nebula, providing an important glimpse into the details of how these molecules form.

The results have been published today in the Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/staf1194