A stunning new discovery reveals that white dwarf stars — once thought to explode in predictable ways — actually detonate through an astonishing variety of mechanisms.
From star cannibalism to violent collisions, these stellar explosions, captured in unprecedented detail, are challenging our understanding of dark energy and the expanding universe. With nearly 4,000 supernovae analyzed, astrophysicists now question whether these cosmic blasts can still serve as reliable distance markers, potentially reshaping our cosmic measurements.
Unveiling the Explosive Diversity of White Dwarf Supernovae
Astrophysicists have discovered an unexpected variety in how white dwarf stars explode in deep space. By analyzing nearly 4,000 such events recorded in detail by a next-generation astronomical survey, researchers have uncovered new insights that could improve our ability to measure cosmic distances and deepen our understanding of dark energy.
For decades, the violent explosions of white dwarfs at the end of their lifecycles have been crucial in studying dark energy — the mysterious force driving the universe’s accelerating expansion. These supernovae also play a key role in creating essential elements like titanium, iron, and nickel, forged under the extreme heat and pressure of their detonation.
This research marks a significant breakthrough in our understanding of stellar explosions, supported by a newly released dataset and 21 related studies published today (February 14) in a special issue of Astronomy & Astrophysics.
Each star is a supernova exploding with the size indicating how bright it appears and the color indicating the color of the supernova, they go from blue (hotter) to yellow (cooler) as they grow older and cool. Credit: Mickael Rigault
Revolutionary Observations from the Zwicky Transient Facility
This unique dataset of nearly 4,000 nearby supernovae is many times larger than previous similar samples and has allowed crucial breakthroughs in understanding how these white dwarfs explode. The sample was obtained by Zwicky Transient Facility (ZTF), a Caltech-led astronomical sky survey, with key involvement of researchers at Trinity College Dublin, led by Prof. Kate Maguire in the School of Physics.
“Thanks to ZTF’s unique ability to scan the sky rapidly and deeply, it has been possible to discover new explosions of stars up to one million times fainter than the dimmest stars visible to the naked eye,” highlights Prof. Kate Maguire.
Exotic New Pathways for White Dwarf Detonations
One of the key results, led by the group at Trinity, is the discovery that there are multiple exotic ways that white dwarfs can explode, including in collisions of two stars in luminous stellar spectacles, as well as the cannibalism of stars by their companions in double star systems.
This is only possible with this sample due to the ability to discover very faint blips combined with large sample sizes. And the surprising diversity may have implications for the use of these supernovae to measure distances in the Universe since the constraints on the properties of dark energy crucially demand that these explosions can be standardized.
A Greater Explosion Diversity Than Ever Expected
“The diversity of ways that white dwarf stars can blow up is much greater than previously expected, resulting in explosions that range from being so faint they are barely visible to others that are bright enough to see for many months to years afterward,” says Prof. Maguire.
