National Repository of Grey Literature 3 records found  Search took 0.01 seconds. 
Chromospheric activity in K giant stars
Überlauer, Jakub ; Karjalainen, Marie (advisor) ; Skarka, Marek (referee)
In this bachelor thesis, we analyze chromospheric activity of two K giant stars, HD 187878 and KIC 3526061, which have been monitored for the past 10 years and have shown variations in their radial velocities that could be caused either by a star's companion, a yet to be discovered type of stellar oscillations or a modulation due to stellar surface features as a result of stellar activity. We explain the physics and theory behind the measurements and we apply it directly to observed data. After the procession of data, we look for periodicities and discuss the results. 1
Automation of processing and photometric data analysis for transiting exoplanets observed with ESO NIR instrument HAWK-I
Blažek, M. ; Kabáth, Petr ; Klocová, Tereza ; Skarka, Marek
Nowadays, when amount of data still increases, it is necessary to automatise their processing. State-of-the-art instruments are capable to produce even tens of thousands of images during a single night. One of them is HAWK-I that is a part of Very Large Telescope of European Southern Observatory. This instrument works in near-infrared band. In my Master thesis, I dealt with developing a pipeline to process data obtained by the instrument. It is written in Python programming language using commands of IRAF astronomical software and it is developed directly for “Fast Photometry Mode” of HAWK-I. In this mode, a large number of data has been obtained during secondary eclipses of exoplanets by their host star. The pipeline was tested by a data set from sorting of the images to making a light curve. The data of WASP-18 system contained almost 40 000 images observed by using a filter centered at 2.09 μm wavelength and there is a plan to process other data sets. A goal of processing of WASP-18 and the other data sets is consecutive analysis of exoplanetary atmospheres of the observed systems.
Z CVn - Still mysterious
Skarka, Marek ; Liška, J. ; Dřevěný, R. ; Sódor, A. ; Kolenberg, B.
We comment on short- and long-term pulsation period variations of Z CVn, a classical RR Lyrae star with the Blazhko effect. Z CVn shows cyclic-like O-C diagram that can be interpreted as a consequence of binarity throught the light travel time effect. We show that this hypothesis is false and that the observed long-term period variations must be caused by some effect that is intrinsic to the star. We also show that the Blazhko period is not simply anti-correlated with the long-term period variations as was suggested by previous authors.

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1 Škarka, Michal
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