Challenging long-held scientific assumptions about dying stars, astronomers have made a stunning discovery.
The groundbreaking finding reveals that white dwarf stars can detonate twice, and well before reaching previously assumed mass limits.
The finding potentially impacts how scientists measure the universe’s expansion.
Using Chile’s Very Large Telescope, researchers spent 29 hours across 39 observations to capture definitive evidence of a “double-detonation” supernova mechanism.
They used a remnant labeled SNR 0509-67.5, located approximately 160,000 light-years from Earth, for their study.
This discovery confirms that certain white dwarf stars can explode through a previously theoretical process where one explosion triggers another, creating a cosmic chain reaction.
The research team was led by Priyam Das from the University of New South Wales Canberra.
They identified a distinct “double-shell” structure with highly ionized calcium layers separated by sulfur, exactly matching predictions for this type of stellar explosion.
By measuring the motion of these calcium shells, they confirmed this was not an illusion but genuine evidence of a spectacular double blast.
Previous studies asserted that white dwarfs could only explode after reaching what is called the “Chandrasekhar mass limit.”
However, the new findings prove smaller white dwarfs can detonate when a thin helium layer ignites first, triggering a second, more catastrophic explosion in the star’s carbon-oxygen core.
“Our observations provide the first substantial evidence from the supernova remnant phase that sub-Chandrasekhar mass explosions through the double-detonation mechanism do occur in nature,” researchers said.
This discovery carries profound implications for how astronomers measure cosmic distances and study the mysterious “dark energy” that drives the universe’s expansion.
Type Ia supernovae serve as cosmic yardsticks due to their consistent brightness levels, helping scientists determine distances across the universe.
The 2011 Nobel Prize was awarded for using these measurements to claim the universe’s expansion is accelerating.
The revelation that these stellar explosions may operate differently than previously assumed could force a recalculation of the universe’s expansion rate, known as the Hubble constant.
This value has been a source of significant controversy among astronomers, with competing measurements yielding different results.
Published in Nature Astronomy, the study highlights the importance of what researchers call “astronomical archaeology” in understanding cosmic explosions.
Telescopes, such as the James Webb Space Telescope, may uncover more instances of these double-detonation supernovae, potentially forcing scientists to reexamine their understanding of how the universe operates and was formed.
