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Viewings: 5297Recently astrophysics proposed a new original method for detecting exoplanets - they should seek the polar lights! The fact that they generate not only electromagnetic waves of the visible range, but also radio waves that are relatively easy to catch because they are well distributed and carry the information about detection processes.
The number of exoplanets is growing every day - improving methods, with which the specialists are finding exoplanets and family exoplanets orbiting their stars. Of course, in their typing initially dominated "Jupiter" - hot and cold, depending on their surface temperature, because large objects easier to identify than a much smaller, similar to the planets of terrestrial group. Striking the tooltip has been embedded in the very typing because Jupiter, the planet's giant of the Solar system, formed a giant magnetosphere dipole structures, and in the magnetosphere magnetic storms are raging and generated polar lights, a much more intense than on Earth.
Auroral manifestations caused by the solar wind that transmits energy to the magnetosphere, and then in the auroral ovals on the Ground around the magnetic poles on ionospheric level flashes enchanting picture of Aurora, always unique, fascinating and simply fantastic and unreal. On Earth, these lights are visible polar night, which lasts up to six months in high latitudes. In polar day they are not visible in the bright light of the Sun, but the companions, exploring the auroral precipitation, fix them in detail.
The study of physics of the magnetosphere, the concept of auroral oval independently from each other and almost simultaneously formulated remarkable Russian scientists YA Feldstein (IZMIRAN) and O.V. Horosheva (SINP). The term "auroral oval" is now widely used in physics of the magnetosphere. In fact, this was the last great geographical discoveries, made from ground-based observations is only pole Earth satellites photographed halo polar lights in a closed ring at the North pole during the polar night at increased the magnetosphere of perturbation. The concept was finally confirmed and became generally accepted.
Paying tribute to our teachers and predecessors, back on the cutting edge of exoplanet research - have practically formulated a working hypothesis their search, according to the observations of the Aurora in the atmospheres! This hypothesis is so simple and elegant, that likely will in the near future, the opening of many exoplanets, at least in this I would like to believe.
So, the latest idea of opening the planets of other stars in their polar auroras. Imagine the sky exoplanets - cold "Jupiter", with family satellites swirling around him in the magnetosphere, vozmuschenii sun-like star that is spewing flare flows in a strong stellar wind. Shining around the poles, running and fluctuating strip light is illuminated ekzoplanetoy the sky!
It should be so, but as long as we just described imaginary picture. To confirm this, it is necessary to ensure registration, to carry out observations of real options flowing auroral events! How to achieve this? Light signal lights still very weak, and he is not visible even in the illuminated hemisphere on Earth in polar day, and in the distant cosmos light of the Aurora obviously indistinguishable. But the Aurora generate not only electromagnetic waves of the visible range, but also radio waves! This phenomenon is intriguing researchers: radio waves are perfectly distributed and carry the information about detection processes.
If initially the methods used for detecting exoplanets gave information about the mass of the planets and orbital parameters, radiation capable of giving information that is not reflected in the previous methods. First, simply discover hidden exoplanet. Second, the radio signals to detect the length of the day, to assess the magnetosphere parameters own magnetic field exoplanets, to assess the impact of the star on its magnetosphere, sometimes even to detect the presence of a planet, satellites!
This was the first registered polar lights on Jupiter - the radio emission. So, it is only in the improvement of methods and accuracy of reception of low-power radio signals from deep space.
Color variations Aurora depend on the length of the electromagnetic waves generated: oxygen emits quantum in the field of greenish-yellow stripes, nitrogen - band red or blue. And the radio waves are emitted in foreplay - rotation of electrons around magnetic field lines exoplanets.
The Aurora was observed on Jupiter, Saturn, Uranus and Neptune. With such enviable consent manifestations in the Solar system - why not to expect such collections exoplanets stars, like our sun? Most likely, everything is repeated. It seems that in some cases several times already had a flare-up, which could be due to similar reasons.
Jupiter is the brightest source of the Aurora in the Solar system. However, they are generated mainly in the ultraviolet radiation, which is absorbed in the Earth's atmosphere, and is therefore not visible. They were first recorded "Voyager 1 spacecraft" in 1979. Today their registers space telescope "Hubble" and orbiting x-ray Observatory "Chandra".
Scientists planetary community were able to calculate the magnetic field of the planet Jupiter long before dispatch "the Voyager 1 spacecraft" to the place of direct measurement for low frequency radio signals. Deep understanding of the physics of Jupiter is very important in the study of information coming from other planets, because the majority of exoplanets resembles Jupiter than a tiny compared to him the Ground.
Radio waves have the advantage that if the planet has a magnetic field, it can radiate radio signals stronger than the stars. There is hope that there is a planet with a very strong and strong private radio emission. Quite the contrary in the optical and infrared parts of the spectrum (where basically looking for exoplanets) - there exoplanets glow much weaker shining hot lights.
On behalf of the exoplanets radio waves to determine the frequency with which they are emitted Aurora, and it depends on the magnetic field strength. Radio waves come in the form of cone beam, rotating together with a planet. For the observer is the signal pulsation, which can determine the period of rotation of the body around its axis. Circular polarization of the signal can help to distinguish the radiation of the planet from the radiation of the stars: star it will likely not polarized.
The first group that undertook the search for exoplanets by radiation, headed by William Erickson of the University of Maryland (USA). Successfully detecting radio signals Jupiter, researchers in 1977, started to monitor 22 closest stellar objects in radioobservatory Clark lake near Borrego springs in California. The sensitivity of the radio telescope have revealed the polar lights, not less than one thousand times stronger jupiterians, but those were not found.
Thirty-five years later, at the present time, the construction of LOFAR telescope, the largest and most sensitive to frequencies below 250MHz. Array, which left ten years, includes more than 45 thousand small antennas. The main part is set in a quiet conservation area in the North-East of the Netherlands, and the rest scattered in France, Germany, Sweden and the UK. Work began in December and to the search for exoplanets planned to start in the near future. It is planned interesting stage in the decision not completed before the task.
Consider ways of solving problems. Exoplanet type Jupiter" can generate powerful radio emission in two cases. First, the configuration of the magnetic field of a planet near the star, may be strongly influenced by the stellar wind... the resultant streams of charged particles produce the Aurora. The modelling performed colleagues Philip Зарк? of the Paris Observatory and Sebastian Assam from the laboratory LATMOS (France), showed that in this way you can determine the slope "hot Jupiter" relative to the plane of the orbit, the tilt of the magnetic field relative to the rotation axis, the rotation period, the orbital period and the magnetic field strength. To identify all this other way is impossible.
Characteristically, a strong surge of radio emission can be associated with the satellite of a planet is discovered and for our Jupiter: lights arise in connection with the fact that the volcanoes of IO thrown in the direction of Jupiter ton of ionized gas every second! Jonathan Nichols from Leicester University (UK) has made calculations, which results revealed the following. On the strength of radio emission stimulated the Aurora influence and speed of rotation of the planet, and the speed of the outflow of ionized gas from its companion, and orbital distance and ultraviolet brightness of the star. As the author believes, such outbursts on the massive and rapidly rotating planets can be detected at a distance of 150 light years. Until confirmation notice failed, despite constant search.
Walid Majeed from the jet propulsion Laboratory of NASA and his colleagues studied extrasolar planets using the GMRT radio telescope, located 80 kilometers North of Pune (India). The main reason for the failure of researchers see the inability tool to record relatively low frequencies. For example, Jupiter does not radiate intense radio waves at a frequency of 40 MHz, and the lower limit of GMRT - 50 MHz. From LOFAR, the average is 10 MHz, but the Earth's atmosphere blocks frequencies below 10 MHz. So, we need to go to the dimensions in space, and only space antenna will provide measurements in the desired range.
Walid Majeed prompts you to install the antenna on the moon. The sensitivity of the telescope can be improved by installation of additional antennas, and by identifying and eliminating noise in the signal caused by other sources of radio waves. Walid Majeed sure that radio astronomy will cope with this task, having equipped not only LOFAR, but the SKA telescope total area of about a square kilometer with antennas in South Africa and Australia.
And if, nevertheless, in a few years, nothing will be discovered it believes opponent Zarqa, this happens due to the fact that there is really no bursts with appropriate capacity for exoplanets, and not due to imperfections of the equipment. The progress and the importance of research in the low frequency range defines the radio astronomy as advanced science of the future decades.
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