Physicists from the Moscow Institute of Physics and Technology (MIPT) and the Space Studies Institute (SSI), RAS have developed an optical technology, which enables them to considerably improve telescopes and directly observe the exoplanets commeasurable with the Earth, the press service of MIPT reports.
"Thanks to using quite a simple optical scheme we can attain the image contrast necessary for direct observation of the Earth-like planets. Of course, as compared to foreign developments our system needs a more complicated control system, but at the same time it depends much less on the temperature stability, the fact significantly simplifying its use in the outer space", - the research head, the MIPT associate professor and the head of the SSI Planetary Astronomy Laboratory, Alexander Tavrov points out.
Difficulties in Finding Exoplanets
Exoplanets, i.e. the planets outside the Solar system were first found at the end of the 20th century, and now people know about the exhistence of over two thousand of them. It is nearly impossible to notice their faint light without special tools - it is "overshone" by radiation of stars. Therefore exoplanets are found by indirect methods, such as fixing weak periodic fluctuations of a star luminosity while a planet is transiting its disk (a transit method), or forward fluctuations of a star under the influence of a planet gravitation (a line-of-sight velocity method). Only in the late 2000s astronomers managed to get direct pictures of exoplanets.
Coronographs - the devices designed in the 1930s for observing the helioshphere without eclipses - is used for such photography. Inside these devices there is "an artificial moon" which shields a part of the vision field, for example, closes a solar disk, making it possible to see a dim solar corona. To repeat it with a star, a much higher level of accuracy and higher telescope resolution are required.
Optical Scheme of the Experiment
Scientists have found a way to make do with rather simple and inexpensive adaptive optics systems in their work and at the same time achieve the highest resolution possible. They drafted off the concept of Extremely Unbalanced Interferometer (EUI) suggested by Djun Nisikava from the Japanese National Astronomical Observatory.
In the EUI light is divided into two beams (strong and feeble) with the amplitudes of approximately 1:10. The feeble beam passes through the adaptive optics system and then both the beams come together again and interfere with each other. As a result the feeble beam sort of "smoothes" the strong beam light and eliminates foreign signals in it.
Approximate characteristics of the invented systems have been established by means of computer modeling. In the future scientists plan to make a laboratory prototype and conduct a number of experiments.
Author: Vera Ivanova