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Recent studies indicate an extraordinary diversity of mechanisms for the explosion of white dwarf stars, which calls into question the established ideas about their role in measuring cosmic distances and the expansion of the Universe.
An analysis of nearly 4000 supernovae using advanced astronomical observations has found that white dwarf explosions occur not only through the traditional thermonuclear detonation scenario, but also through collisions with other stars or their “stellar cannibalization” in binary systems. The discovery calls into question the accuracy of using such supernovae as “standard candles”—objects of predictable luminosity used to measure distances in the universe.
A study published in a special issue Astronomy & Astrophysics February 14, was made possible by revolutionary observations made with the Zwicky Transient Facility (ZTF). This unique facility, which scans the sky with extraordinary speed and depth, has allowed us to record explosions that are a million times fainter than the faintest stars visible to the naked eye.
Of particular significance is the discovery of exotic pathways for white dwarf detonation, including cases of mergers of two white dwarfs or explosions caused by their absorption of matter from neighboring stars. The diversity of supernova scenarios discovered could radically change our understanding of dark energy, since precise cosmological measurements have been based on the assumption that all supernovae of this type have the same brightness.
The results of the study force the scientific community to reconsider established models of the evolution of white dwarfs and their final explosion, opening new perspectives for studying the mechanisms of cosmic catastrophes. Further studies will determine how this diversity affects our ability to accurately estimate distances in the Universe, which is critical for determining the rate of its expansion.
