Department of astronomy, KAFZM FMFI UK

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Research


Solar physics

Research of the Solar physics is mainly oriented on study and diagnostics of non-thermal distributions in coronal plasma and transition area dynamical processes in the Solar atmosphere and eruptions. Theoretical analysis of non-thermal electron distributions and non-thermal electrons effects on ionization and excitation equilibrium in the solar corona showed, that non-thermal distributions are important and affects the intensity of spectral lines. That allows proposing methods to identify the type of distribution. Diagnostic methods developed by Dzifcakova, E. (from 1995) and Kulinova, A. enable to prove presence of non-thermal electrons, which are present during magnetic reconnection during solar eruption and are spreading along magnetic lines. Also there is a big concern in solar eruption, during which great amount of energy is released as it is proposed because of dissipation of magnetic field. The team is using data from chromospheric telescope at AGO and data from satellites SOHO, TRACE, RHESSI. Data and its interpretation could help to explain the mechanism of eruption progress and maybe its forecast. In addition to H-alpha sun observation there is a plan to extend it in Ca line data to fully cover the chromosphere events.


Interplanetary matter

The research was closely related to the research of the AU SAV from the beginning. Since the eighties photographic material was obtained from observatory Skalnate Pleso and also master theses were made under guidance of scientists from AU SAV. The original research dealt with the meteor radiation, color index estimate and other physical characteristics of meteors, composition and evolution of meteor showers, especially Orionids, determination the the mass flux of meteors onto the Earth, distribution of the particles, density and structure of meteors. Cooperation with Kyjev University was established. After 1989 and after completing the AGO observatory, independent research has started. Present research has been focused on the dynamical and physical properties of small bodies in the Solar system ranging from the interplanetary dust particles to the asteroids and comets. Also there is a scientific interest in the near Earth objects, which represent substantial impact risk to our planet. The key part of practical work is the astronomical observation of the small bodies made by 0.60m reflector at AGO. The current limiting magnitude reaches at 20.5 during decent atmospheric conditions (with the CCD camera Ap8). The observatory discovered about 160 Main belt asteroid and two Near Earth asteroids, which ranks AGO among the most successful observatories in Europe in discovering of the asteroids. Astrometric program is oriented towards the accurate positions of asteroids and comets under international cooperation of the Minor Planet Center (Harvard Smithsonian). High astrometric accuracy granted AGO The planetary society Gene Shoemaker grant in 1998. AGO is also included in the confirmation and follow up of newly discovered Near Earth objects with cooperation with Ondřejov observatory.

Comets

Another major interest is the bright comets, especially new and active periodic comets at their perihelia and comets with the peculiar activity. Observation of coma and tail structures and brightness estimate are made. Faint details are gained using image processing, which allows study of close core zone and core rotation. Interesting results were obtained from observing comet 29P/Schwassmann-Wachmann (1995-1996), 73P/Schwassmann-Wachmann nuclei break-up, fragments escaping primary body of C/1995 Y1 Hyakutake and rotation of C/1995 Halle-Bopp (Galád, A.; Pravda, A., Gajdos, S.; Vilagy, J.; Paulech, P.).

Photometry

The goal of differential CCD photometry is light curve determination and analysis, from which rotation periods, albedo, shape, orientation of spin axis and binaries can be derived. Observations have been made mainly in the cooperation with Ondřejov observatory. Primary goal were the Main Belt asteroids, but the aim shifted to the Near Earth asteroids, binaries and tumblers (Galad, A.; Kornos, L., Toth, J., Vilagy, J., Gajdos, S.).

Radar

There is a forward scatter radar receiver at AGO as the part of Bologna-Lecce-Modra radar range, built in 1992 in cooperation with Italian academy of science (ISAO CNR). Since then, systematic radar observations are made to explore meteor shower and sporadic meteors frequencies and physical properties of meteoric matter with interaction with the upper atmosphere and zone concentration (Hajdukova, M., Porubcan, V., Zigo, P.Kornos, L., Gajdos, S.).

Meteors

The European bolide network station is located at the premisses of AGO. It consists of two fish-eye objectives that project the all-sky onto the photographic plate that detect bright bolides. Data from two or more stations (besides AGO) allow to compute and reconstruct the track of meteor in the atmosphere and also it’s orbit in the space. The world famous picture of Leonid shower from 16./17. September 1998 was published (Toth, J., Paulech), which allows to discover until unknown filament of Leonid shower (Porubcan, V., Kornos, L., Toth, J. ). Also the station detected the fall of Turji-Remety meteorite with estimate mass around 450kg, which has not been find until now (Porubcan, V., Spurny, P.) From 2005 there were experiments with video-regime cameras and video detection of meteors, and finally from 2007 launching all sky video meteor detection, which allows detect meteors down to +3 in magnitude (Toth, J.). The TV camera was used in the joined airborne Draconid 2011 expedition.


Interplanetary dust

The study of the cosmic dust particle dynamics brought interesting result in the field of the celestial mechanics. We study the electromagnetic radiation effect on microscopic particle motion considering the relativistic effects, extinction, dispersion, absorption, thermal emission and Poynting-Robertson effect affecting non-spherical particles. It has been shown, that interstellar non-spherical particles can be captured in the solar system (Klacka, J., Kocifaj, M.).

 

 

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