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When you tune in to Bec & Asa, you never know what fascinating corner of the universe you’ll explore next. This time, the team welcomed astronomer Dr Laura Drisson from the University of Sydney to unpack one of the strangest and most spectacular discoveries in our galaxy: a rare triple-star system known as APEP.
Let’s break down why astronomers all over the world are excited – and why this cosmic giant gives us surprising clues about how stars live, die, and even help create the carbon that makes life possible.
What Is the Triple-Star System APEP?
We often imagine stars as solitary, but many live in pairs, or even trios. APEP is one of those rare triple-star systems, but it’s far more unusual than that.
Two of its stars sit at the centre, orbiting each other in an immense cosmic dance. These aren’t just any stars, they’re Wolf-Rayet stars, some of the hottest, oldest, and most volatile stars in the Milky Way. A newly confirmed third star, discovered through recent research, also orbits with them.
This makes APEP not just a triple-star system, but one of the rarest and most dramatic ones known.
How Scientists Confirmed the Third Star
Astronomers first spotted APEP back in 2018, but they weren’t sure whether the third star they observed was truly part of the system or simply sitting in the background.
“Distance is really hard in astronomy,” Dr Laura explained. While the two central stars were clearly companions, the third star remained a mystery, until recently.
Using new images from the James Webb Space Telescope (JWST), researchers saw something remarkable: the third star slices right through the swirling dust shell created by the inner pair. That movement confirmed it, this star isn’t just nearby. It’s part of the family.
A Stunning Dust Shell… and a Cosmic Clue
One of the reasons APEP caught scientists’ attention is its breathtaking spiralling dust shell, which looks almost like a giant cosmic seashell floating in space.
Here’s how it forms:
The two central stars orbit each other every 190 years.
When they draw close, their powerful stellar winds crash together.
That collision blasts out carbon-rich dust in huge expanding shells.
JWST captured four distinct shells, revealing centuries of activity.
Dr Laura compared the shells to something surprisingly down-to-earth: tree rings.
Just as rings show the age and history of a tree, these dust spirals reveal the long-term behaviour of the stars inside.
Why APEP Matters: Understanding Carbon Creation
APEP’s stars don’t just look beautiful, they’re incredibly important.
Wolf-Rayet stars like these are exceptionally rare. In fact, Dr Laura says there are only about 1000 stars like them in a galaxy containing tens of billions.
Yet these rare stars have created much of the carbon in our Milky Way.
Carbon forms the backbone of all life, from plants to animals to humans. By studying systems like APEP, astronomers learn more about how essential elements for life are forged and spread across the galaxy.
Should We Be Worried About APEP Exploding?
Before your imagination runs wild, no, the dust shells are not heading our way.
But Dr Laura did confirm that the stars in APEP will eventually go supernova. The two central stars are around 10-20 times the mass of our Sun, and the third star is a massive 40-50 times its size.
A supernova isn’t exactly a gentle event, but thankfully:
APEP is very far away,
the explosion is thousands of years into the future, and
it poses no real threat to Earth.
“It’s probably going to be fine,” Dr Laura said with a laugh, before admitting, “but you never know.”
Why We Love Exploring the Universe
Segments like these remind us just how vast and astonishing God’s creation is. From swirling galaxies to tiny dust particles, every part of the cosmos points to majesty, order, and wonder.
As Dr Laura wrapped up her visit, it was clear: APEP is more than just a scientific curiosity, it’s a breathtaking window into how stars shape the universe itself.
You can check out the full chat with Dr Laura below.