Astronomers have discovered a binary star system in which matter flows from a companion star to a white dwarf. In this respect informs University of Bonn.
White dwarfs explode as supernovae when their mass exceeds 1.4 solar masses. Such supernovae are considered not only the main source of iron in the Universe, but also an important tool for astronomers: the brightness of these SN Ia flares is always approximately the same, and therefore they are used as “standard candles” for determining distance. to the source.
Now scientists have detected another such dwarf with the eROSITA telescope, thanks to ultra-soft X-ray emission from nuclear fusion in gas spilled close to the white dwarf’s surface. What is unusual in this case is that it is helium, not hydrogen, that overflows and burns. The measured luminosity indicates that the mass of the white dwarf is growing more slowly than previously thought possible, necessitating a revision of the SN Ia supernova number.
“The source of super soft X-rays [HP99] 159 has been known since the 1990s, when it was first observed with ROSAT and now eROSITA,” explains Jochen Greiner. “We have now identified it as a source in the Large Magellanic Cloud. In its spectrum, we found mainly helium emission lines from the accretion disk.”
The existence of such white dwarfs has been theoretically predicted, but astronomers have never been able to observe them. The brightness observed in the X-ray range allows us to conclude that the combustion of helium flowing into the white dwarf is offset by its rapid spin, making a future supernova explosion very likely.
Formerly artificial intelligence created equation for estimating the mass of galaxy clusters.
Source: Gazeta
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