Actual PhD thesis for 2012/22:

Application of machine-learning to the study of eclipsing
binary stars
Type: PhD thesis
Supervisor: Štefan Parimucha
Anotation: Eclipsing binary stars are variable stars whose light curve analysis allows us to determine the basic parameters of the components, such as their effective temperatures, radii, luminosity, and in combination with radial velocities also the masses and mutual distances of the components. These variable stars are one of the most commonly discovered types of variable stars. Archived data from satellite (KEPLER, TESS, GAIA) as well as from ground-based projects (SuperWASP, ASASS…) contain tens of thousands of eclipsing binary stars. It is assumed that planned large-scale surveys such as PLATO and/or Vera C. Rubin Observatory (LSST) will discover several millions of eclipsing binaries. Their analysis using up-to-date conventional methods is practically impossible. One of the possible ways of their study is the application of machine-learning methods to large data sets and the determination of parameter boundaries from their light curves.

Slovak virtual observatory – SKVO
Type: PhD thesis
Supervisor: Štefan Parimucha
Anotation: The Virtual Observatory (VO) is a network of various data archives and services that, together with various software packages, allow free access to observing data for a wide astronomical community. The vast majority of data available in VO are spectroscopic and image data together with various catalogs. Despite their great importance, photometric data are on the verge of interest in VO, mainly due to the lack of standards for photometric data. There is also no platform for data from small telescopes, whose data are often not available to the astronomical community.

Multifrequency study of activity of symbiotic stars
Type: PhD thesis
Supervisor: Rudolf Gális
Anotation: Symbiotic systems belong to a group of interacting binaries, in which the physical mechanisms related to the mass transfer and accretion are responsible for observable activity of these eruptive variable stars. Our previous investigation showed that a long-term monitoring of the objects during the whole cycle of their activity in a broad spectral range is necessary for better understanding of these physical processes. The main goal of the PhD thesis is study of behaviour of accretion disks, impacts, jets and other phenomena related to the mass transfer in different phases of activity in the symbiotic systems that have recently manifested Z-type outbursts (e.g. AX Per, AG Dra and Z And) using own photometric and spectroscopic observational data and modelling of their light curves and spectra.

Short-period cutoff of contact binaries
Type: PhD thesis
Supervisor: Theodor Pribulla – Astronomical institute of the Slovak Academy of Sciences
Anotation: Contact binary stars show an orbital period cut-off at about 0.20 days. Systems with shorter orbital periods are not observed. This observational fact has still not been satisfactorily explained and the number of objects with orbital periods shorter than 0.22 days is only about 25. This is related to another observational fact: contact binaries with spectral types later than K are not observed. It is not clear, if the period cut-off is an observational bias (these systems are intrinsically faint) or it is a real effect caused by the internal structure change between the K and M spectral types (fully convective interior for stars later than about M5). A possible explanation can be slow evolution of low-mass stars. Hence, such systems could not have yet evolved in the Universe.



Actual master thesis:

Actual Bc. thesis: