Teardrop Star Reveals Hidden Supernova Doom
Anti-aristarchus writes:
Teardrop star reveals hidden supernova doom:
Astronomers have made the rare sighting of two stars spiraling to their doom by spotting the tell-tale signs of a teardrop-shaped star.
The tragic shape is caused by a massive nearby white dwarf distorting the star with its intense gravity, which will also be the catalyst for an eventual supernova that will consume both. Found by an international team of astronomers and astrophysicists led by the University of Warwick, it is one of only very small number of star systems that has been discovered that will one day see a white dwarf star reignite its core.
New research published by the team today in Nature Astronomy confirms that the two stars are in the early stages of a spiral that will likely end in a Type Ia supernova, a type that helps astronomers determine how fast the universe is expanding.
[...] Type Ia supernovae are important for cosmology as 'standard candles'. Their brightness is constant and of a specific type of light, which means astronomers can compare what luminosity they should be with what we observe on Earth, and from that work out how distant they are with a good degree of accuracy. By observing supernovae in distant galaxies, astronomers combine what they know of how fast this galaxy is moving with our distance from the supernova and calculate the expansion of the universe.
[...] "There is another discrepancy between the estimated and observed galactic supernovae rate, and the number of progenitors we see. We can estimate how many supernovae are going to be in our galaxy through observing many galaxies, or through what we know from stellar evolution, and this number is consistent. But if we look for objects that can become supernovae, we don't have enough. This discovery was very useful to put an estimate of what a hot subdwarf and white dwarf binaries can contribute. It still doesn't seem to be a lot, none of the channels we observed seems to be enough."
Journal Reference:
Ingrid Pelisoli, P. Neunteufel, S. Geier, et al. A hot subdwarf-white dwarf super-Chandrasekhar candidate supernova Ia progenitor, Nature Astronomy (DOI: 10.1038/s41550-021-01413-0)
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