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The Russian orbital observatory "Spektr-RG" has detected a nova flare

Category: English  |   17 Май 2022    

The Russian orbital observatory "Spektr-RG" has detected a nova flare

The German eROSITA X-ray telescope installed on board the Russian Spektr-RG orbital observatory accidentally detected a flare generated by an awakening new star in the constellation of the Grid. The results of the scientists' observations were published in an article in the journal Nature.


"Our observations of the flare activity of the YZ star in the constellation Grid confirmed for the first time that new stars produce well-marked bursts in the X-ray wavelength range. These measurements helped us to accurately measure the total energy of the new star flares and reveal the processes in the photosphere of stars that generate these cataclysms," the researchers write.


The so-called new stars are binary luminaries that consist of a large-mass white dwarf, the core of a large burnt-out star, as well as a normal luminary that is slightly inferior to the Sun in mass and surface temperature. These stars rotate around each other in such a way that the white dwarf constantly pulls over the matter of its neighbor, which gradually accumulates on its surface.


When the mass of the "stolen" plasma reaches a critical point, a powerful thermonuclear explosion occurs, as a result of which the brightness of the new star temporarily increases tens of thousands of times. A group of European astronomers led by Jorn Wilms, a professor at the University of Erlangen (Germany), followed the first phases of this cataclysm using the eROSITA X-ray telescope installed on board the Russian Spektr-RG orbital observatory.


Explosion of a new star

Scientists made this discovery randomly during the second survey of the sky, which is part of the main scientific program of the Spektr-RG mission. During observations of the constellation of the Grid, astronomers recorded a powerful flash that came from a compact object 8.2 thousand light-years away from Earth.


Subsequent observations and analysis of archival data indicated that at this point there is a known new star, YZ in the constellation of the Grid. This forced scientists from many other scientific projects, including the Fermi and NuSTAR orbital telescopes, to start observing this event in the entire electromagnetic wave range.


Thanks to a happy coincidence, eROSITA recorded a thermonuclear flare of a new star in the early stages of its birth. For the first time, this allowed astrophysicists to trace the processes in the upper layers of the white dwarf's photosphere that precede the explosion of hydrogen accumulated on its surface.


These measurements showed that the brightness of the star's surface at this point in time is close to the so-called Eddington limit, the theoretical limit on the maximum luminous intensity of any object in space. This confirmed the generally accepted theory that a significant part of the mass of the "stolen" plasma is ejected by white dwarfs back into space during the outbursts of new stars, summed up Professor Wilms and his colleagues.


Source: TASS

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