The last decade of the 20th century was marked by the epochal discovery of astronomers: almost 400 years after the death of J. Bruno received confirmation of his idea about the existence of planets outside the Solar system. Such objects were called exoplanets.
After in 1995 proved that there was a planet near the star 51 Peg, astronomers discover lots of exoplanets every year, the account goes on hundreds. To do this, researchers have a variety of ways. For example, if the illumination of the stars for some time waning, this may be due to a planet passing in front of it. However, this requires that the telescope was located in the orbital plane of the planet.
The planet can be detected by the gravitational influence they exert on their stars. The idea that planets revolve around stars, not exactly, in fact the whole system is moving around a common center of mass. The star is the most massive object is the movement of the least significantly, and yet it is.
The emergence of devices equipped with PZM-matrices with a large number of pixels allowed to use to search for exoplanets microlensing. Body with a large mass – including the planet – distort the space in which light travels, making it possible to observe a slight enhancement of the glow of the stars, a kind of «flash» between the star and the observer passes the planet.
Another method used in the study of pulsars, binary stars – in a word, where it comes to cyclic processes. If the cycle of this process gets off, so it interferes with some additional object that may well be exoplanets.
Only a few exoplanets can be directly observed and photographed using telescopes. These photos were taken in the observatories VLT and Gemini, respectively located in Chile and Hawaii.
To detect the planet and even to confirm its existence is not enough, we need to study its properties. The mass of the planet is determined by its gravitational effects on the stars. If the stars revolves around a few planets, another available method is the study of their gravitational influence on each other. To reduce the luminosity of the star during the passage of the planet in the background set the size of the planet. Knowing the mass and the size, compute density, and it lets you know whether it is a gas giant, the planet earth type or something else. Analysis of the spectrum of light reflected by a planet, gives an indication of the composition of its atmospheres. Watching as the planet goes behind the star, scientists can estimate the distribution of heat on its surface and on the basis of these data to compile a meteorological map of the planet.
The existing methods, unfortunately, can’t answer the most interesting question is whether habitable exoplanets. Scientists can only estimate the principal possibility of life on a specific planet: at what distance from the star it orbits, what is the temperature on its surface, there is liquid water, what is the atmosphere on the basis of such data, you can either completely eliminate the presence of life, either to believe that maybe, but not to approve it. However, the study of exoplanets is just beginning.