The James Webb Space Telescope has peeled back the veil on one of the Universe’s most spectacular objects: the Butterfly Nebula.
Located 3,400 lightyears away and visible from Earth in the constellation Scorpius, this glowing cloud of gas and dust marks the last breath of a dying star.
And Webb’s infrared instruments are revealing details that astronomers have never seen before.
A beautiful dying star
A planetary nebula is created by a dying star, and is arguably one of the most beautiful objects you’ll see in the Universe.
The term ‘planetary nebula’ is a complete misnomer, however, as they have nothing to do with planets.
They’re so-called because they often look like round, puffed-out objects, produced as a dying Sun-like star expels its outer layers into space.
In this way, planetary nebulae offer an insight into what our Sun might look like when it eventually dies.
This cloud has wings
The Butterfly Nebula isn’t a round, spherical shape, but instead has a pair of ‘wings’, which give it its nickname.
Formally catalogued as NGC 6302, this dying star is ejecting material in two streams of gas that are firing outwards into space in opposite directions.
These streams are sculpted by a thick band of dust that forms the body of the butterfly.
The dusty ring blocks starlight for the human eye, which means telescopes that operate in visible wavelengths can’t see the dying star at the centre.
But the James Webb Space Telescope, which sees in infrared, can pierce through the dust.
Webb gets a closer look at the Butterfly
Astronomers pointed the Webb Telescope’s Mid-Infrared Instrument (MIRI) at the nebula’s hidden star.
Blazing at 220,000°C, (396030°F), it’s one of the hottest known central stars in a planetary nebula in our galaxy.
What’s more, the star’s intense radiation charges the surrounding gas, making the nebula glow in vibrant colors.
Webb’s observations also reveal what the dust is made of.
Crystalline silicates, similar to quartz, mix with larger-than-expected dust grains that have been growing for thousands of years.
Beyond the dusty torus, astronomers detected layered shells of different elements, including iron and nickel blasting out in jets.
Webb also spotted carbon-based molecules called polycyclic aromatic hydrocarbons (PAHs).
On Earth, PAHs show up in smoke and soot, but finding them in the Butterfly Nebula is a key discovery.
They seem to have formed when stellar winds collided with surrounding gas, and this may be the first evidence of PAHs emerging inside an oxygen-rich nebula.
These findings paint a clear picture of how dying stars enrich the galaxy with dust and complex molecules, the very ingredients that eventually form new stars and planets.
Read the full paper at academic.oup.com/mnras/article/542/2/1287/8241385