Double Explosion Reveals New Star Life Cycle
Astronomers have discovered direct evidence of a star undergoing a double explosion, challenging existing theories about stellar evolution. The finding promises to reshape our understanding of supernovas and the universe’s chemical composition.
Unexpected Discovery in Distant Supernova Remnant
Located approximately 160,000 light-years from Earth, the supernova remnant SNR 0509-67.5 spans 23 light-years. Research indicates that the star within this sphere exploded twice, a phenomenon previously unconfirmed.
Premature Detonation Defies Expectations
The progenitor star was a white dwarf, with mass comparable to the sun but size similar to Earth. Current models suggest white dwarfs must reach 1.4 solar masses, the Chandrasekhar limit, before exploding as Type Ia supernovas. However, observations indicate that the star in SNR 0509 detonated before reaching this limit.
Helium Layer Triggered Cataclysmic Event
**Priyam Das**, from the University of New South Wales in Australia, suggests a thin helium layer on the star’s surface ignited, causing a smaller initial explosion. This, in turn, triggered a larger explosion in the carbon-oxygen core. According to **Das**, this chain reaction occurred when the star was only about one solar mass.
Unique Chemical Signatures Unveiled
Using the Multi Unit Spectroscopic Explorer (MUSE) at the European Southern Observatory (ESO), scientists analyzed the light from the supernova remnant. This analysis revealed a distinctive chemical structure: a double calcium ring with a sulfur ring in between, indicative of a double explosion. Single-explosion supernovas or head-on collisions between two stars do not produce such rings.
The presence of sulfur and calcium helps scientists better understand the conditions and processes during stellar explosions. In 2023, the James Webb Space Telescope detected sulfur in the supernova remnant SNR 1987A, providing further insights into the distribution of elements after such events (NASA).
Implications for Measuring the Universe
The research implies that white dwarfs can explode before reaching the Chandrasekhar limit, impacting calculations for Type Ia supernovas used as “standard candles”
to measure the universe’s expansion rate. Double explosions alter the energy output, the amount of matter ejected, and the elemental composition of these supernovas.
Impact on Cosmic Chemistry
These explosions are significant contributors to the iron found in the universe, as well as calcium on Earth. Sub-mass explosions like these affect the elemental mixture and influence the chemical composition of new stars and planets.
Future Research
Researchers are actively searching for similar remnants in the Large Magellanic Cloud and the Milky Way, utilizing advanced instruments like MUSE. Further discoveries of double-ring structures will help determine the prevalence of these rare explosions.
Rewriting Stellar Explosion Theories
The direct proof that explosions in a thin helium layer can destroy a star validates theoretical discussions spanning decades. The discoveries suggest that “time, patience and sharp observation power is preparing to rewrite books about star explosions.”
