Scientists have uncovered the hidden core of one of our galaxy’s most spectacular phenomena, giving scientists a rare chance to see what may one day happen to our own sun.
The James Webb Space Telescope (JWST) has peered through a dense shroud of dust that has hidden the heart of the Butterfly Nebula since its discovery in the 1970s.
The discovery may give us some indication of what could happen to our own sun. In about five billion years it will run out of fuel, and when it does it will swell, shed its outer layers and form a bright cloud of gas and dust known as a planetary nebula.
The Butterfly Nebula, around 3,400 light years away, is an example of this process now taking place around another star.
“These results may have given us a glimpse of the future, of what our sun could potentially turn into — and it’s full of surprises,” said Dr Olivia Jones of the UK Astronomy Technology Centre.
The nebula has amazed astronomers since the 1970s, when its butterfly shape was first seen. But its central star was hidden behind thick dust until JWST used its mid-infrared instrument, called Miri, to look inside.
Miri, which was largely built in the UK, detects light invisible to human eyes but able to pass through dust. Using this, scientists not only saw the central star but also the activity around it.
They found tiny crystals, including quartz, forming in a doughnut-shaped ring of material at the centre. Jets rich in iron and nickel were shooting out, and for the first time, researchers detected molecules known as polycyclic aromatic hydrocarbons inside a planetary nebula. On Earth, these molecules appear in smoke or even burnt toast.
“We were surprised at just how dynamic the nebula is,” said Dr Mikako Matsuura of Cardiff University, who led the study. “The typical assumption is that planetary nebulae exist in a state of inactivity … Instead, we see what resemble 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.”
The butterfly’s wings stretch across three light years, yet the star at its centre is only a few thousand kilometres wide. Its surface is scorching, at about 220,000C. Scientists say this spectacular stage will last only about 20,000 years.
The “butterfly” shape is thought to come from the thick band of dust at the centre, known as a torus. This ring channels the star’s gases into two giant lobes, creating the wings that make the nebula.
