GK Perseus

GK Perseus was discovered on February 21, 1901 by Scottish amateur astronomer Thomas David Anderson ( (eng.) Thomas David Anderson ) from Edinburgh , when he cast a casual glance at the sky and saw a third-magnitude star in the constellation Perseus . Anderson was an experienced observer: before that he had already discovered T Aurigae , also a new star, in 1892 . The next day, he reported on his observation at the Greenwich Observatory and was surprised to realize that he was the pioneer of the first new star of the 20th century ^[5] .

In Russia, the 15-year-old Kiev gymnasist Andrei Borisyak (1885–1962) (with his friend AI Baranovsky) saw her first. He was several hours ahead of professional astronomers and was awarded for this discovery considerable honors at that time. Emperor Nicholas II personally presented him with a Zeiss telescope , and the Russian Astronomical Society accepted him as a full member. Later, on the recommendation of Flammarion, Borisyak became also a member of the French Astronomical Society . Dreaming of linking his fate with astronomy , Borisyak entered the university , but was unable to master complex mathematical disciplines. As a result, he became a professional musician and wrote the textbook "Cello School" ^[6] .

Having received the outbreak report, astronomers at the Harvard Observatory found that a new asterisk with a 13 ^m asterisk was in place of the new one, which showed slight fluctuations in brightness. It happened so that this region of the Perseus constellation was photographed two days before the discovery of Dr. Anderson and the star on the photographic plate was at the minimum of brightness. Thus, in less than two days, the star raised its brightness from 13 ^m to 3 ^m , increasing the luminosity 10,000 times.

For the next two days, the star continued to increase its brightness, although somewhat slower, until it reached a maximum value of 0 ^m , 2, equaling its luminosity with the Chapel and Vega . A total change in brightness was fourteen magnitudes, and this value was achieved in less than four days. Immediately after the peak of brightness, it quickly began to fade away (although not as fast as it flashed): six days after the maximum it was a second-magnitude star, and after four weeks it was the fourth. At this stage, a series of oscillations began with a periodicity of about four days and an amplitude of 1 ^m , 5. These fluctuations continued for several months while the star continued to fade. Novaya returned to a state of rest and its usual size of 13 ^m in eleven years ^[5] .

Six months after the outbreak, the French astronomer Camille Flammarion and his colleagues said that they photographed the “luminous envelope surrounding the star.” This puzzled astronomers, because in this case it turns out that the shell, dropped by the explosion of a new one, flies at a speed faster than the speed of light . It usually takes years before material thrown out at such events can be resolved into ground-based telescopes. Charles Perrine and George Ritchie also noted the changing position of the areas of shell density in photos taken from month to month. The shell in the GK Perseus system expanded at a tremendous speed - 11 arc-minutes per year - ten times the speed of light, which caused a stir among astronomers and in the popular press ^[5] .

The Dutch astronomer Jacob Kapteyn was probably the first person to say that the “flying out” shell is not really moving at all. He suggested that what we see is in fact a light echo of a flash. Kaptein's theory only partly explained the situation. The paradox was resolved in 1939 by .

He suggested that the presence of a dust envelope before the outbreak of GK Per would explain the superluminal echo around this star. A flash of new is, in fact, a spherical stream of light, gradually highlighting the surrounding dust. The radiation going directly to the earth observer, highlights the dust along the line of sight towards the Earth. Other rays flash dust away from the line of sight after some time, and then deviate towards the Earth. These rays actually traveled a relatively small additional distance, but the echo seems to have increased by the distance between the direct beam and the deflected rays, so the expansion appears to be faster than the speed of light. The apparent speed of movement is infinite at the moment when the light directed at the observer for the first time highlights the dust, but it slows down when the ring of light grows ^[7] . The observer sees the light of an imaginary expansion of the surface around a new one, which is the surface of an elongated ellipsoid , where the new and the Earth are the foci of this ellipsoid. If dust is present on the line between the new and the observer, then the effect of "superluminal" expansion occurs. Almost fifteen years after the explosion, the nebular envelope around GK Perseus finally became fully visible and was called The Firework Nebula ^[8] . The structure of this nebula is explained by the fact that the expansion occurs in a dense interstellar medium ^[9] . Its mass is estimated to be more than 0.0001 solar masses , and the expansion velocity reaches 1200 km / s, its diameter is still less than a light year ^{[10] [11]} .

GK Perseus (as well as similar cataclysmic variable stars) is a close binary system consisting of a compact white dwarf absorbing the substance of a giant cold star of spectral type K2IV through an accretion disk ^[12] . When the mass of a substance reaches a critical value, a thermonuclear flash occurs, ejecting stellar matter into the surrounding space, but not destroying a white dwarf. The system of GK Persei is very close: the orbital period of a white dwarf is two days ^[5] .