Astronomers call sporadic outbreaks of events - they are sudden and unpredictable. Moreover, it is known from observations that the red dwarfs is inherent in a very intense flare activity. They belong to the less massive stars than our Sun, and is also considered suitable for the role of the cradles of life. Recently, scientists have discovered the cause of this phenomenon.
Interest in the phenomenon of flares in red dwarf is quite natural - the fact that such a powerful flash can be disastrous for the emerging or developed biota. And after all red dwarfs have planets, some of which are quite normal conditions for the existence of life.
Against the backdrop of giant stars, red dwarfs look slightly glowing stars, so their observations are made in a limited habitat near. In our galaxy, in the constellation Ursa Major, is a binary star system consisting of two red dwarfs - they are separated by a distance of 190 astronomical units. In the scale of the solar system is four times the distance from the Sun to Pluto.
This star system is called Gliese 412, and studied quite thoroughly. Its stars, red dwarfs are: first - Gliese 412 A mass falls short of half the mass of the sun, and the light is much weaker - is only about 2 percent of the luminosity of our stars. The second star Gliese 412 B is much less massive and has a constant luminosity. This is a very dim star class M6 is a hundred times weaker than its neighbor, Gliese 412 A! But the brightest moments of stellar flares exhibit similar variable stars, this is truly their finest moment - the strongest burst of brightness is found in the observations.
The theory of stellar flares explains these phenomena transformations in a complex hierarchy of stellar magnetic fields that govern the stellar activity. In the sun it can be clearly seen: the image of a new set of activities with spots, it grows and mutates, and pops up when a new strong magnetic flux, there is a remix of the lines of force in the conducting plasma environment is implemented strong energy conversion in the Sun, which is seen as a flash. This release has a giant kinetic energy from the sun and flies at speeds of more than 1000 km / s. On red dwarfs occur giant flash convective plasma environment of these stars in the same way electrical discharge generates flare activity.
Vakhtang Tamazyan, a professor at the University de Santiago de Compostela (Galicia, Spain), with a group of colleagues in Spain and Armenia have identified and investigated an extremely powerful example of the flare process: variable star WX UMa increased its brightness by 15 times for 160 s. Its surface temperature equal to 2800 K, in the region of the flare event reached 18 000 K - that is the surface temperature of the blue giants of spectral type B! But the blue giants feed their monstrous luminosity of the constant influx of energy from the depths of the star. In the case of the red dwarf detects the temperature of the coronal heating of the flare loop, the active formation in the upper atmosphere of the red dwarf, luminosity, which initiates realized the magnetic field energy.
A similar change in the brightness of the coronal loops on the Sun was found in the space experiment Coronas-F in IZMIRAN them. NV Propagation RAS, marked the opening of the State Prize. Usually solar corona is heated to about 2 million degrees in the experiment Coronas-F have observed heating to 20 million degrees. On red dwarfs, which are typical flare stars, as realized volatility of complex magnetic fields. These phenomena are not easy to detect because of the weak luminosity, since more than 60 light-years from Earth, red dwarfs can not be seen to be the limit of modern technical features.
The star couple, which includes star WX UMa, gives researchers a unique opportunity to investigate whether the frequency of outbreaks linked and relative position of a pair of rotating around each other luminaries - emphasizes Vakhtang Tamazyan. The study of a binary system, where the red dwarfs interact with each other gravitationally, allows you to explore the issue of connectivity flare processes and expand the understanding of the physical nature of unique flares on red dwarfs.
Simultaneously with the observation WX UMa star team of astronomers studied four additional binary systems with red dwarfs by observing their flare activity. Powerful flares observations are not recorded, but nevertheless three dwarfs are brighter in flares, and only one of them at the time of the observations did not show such activity. So, as it turned out, flare characteristics of red dwarfs do not possess the identified frequency. As a result, scientists have suggested that time in such a short time, there were a large number of outbreaks in binary systems, it seems that they appear due to the influence of light companion.
It should be noted that the raging flashes red dwarfs are not like our much more stable in this regard, Sun. Solar flare activity originates on the rising part of each 11-year cycle, reaches its climax at the maximum cycle, dropping to the lowest manifestations in the solar minimum. Although exceptions to the general trends have been observed: in 2003, shortly before the minimum was a series of powerful solar flares, which attracted great attention of specialists.
Such strong solar flares are called X, points M and H. outbreak investigations, as the most energetic manifestations of solar and stellar activity, carefully recorded and analyzed according to current space-based observatories. Their nature is becoming increasingly clear to scientists, but the forecast still flare events is only a probability, not accurate. But it is possible that the process of improving the knowledge of such a prediction may appear ...
