National Repository of Grey Literature 22 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Flare stars
Kára, Jan ; Wolf, Marek (advisor) ; Švanda, Michal (referee)
The works deals with the study of the flare stars, which is a group of stars for which sudden brightening can be observed. The work focuses on a star GJ 3236, which is a low-mass eclipsing binary and on which numerous flares have been observed. For the analysis of this system spectroscopic and photometric data were used, which were obtained at various observatories. Parameters of the binary system have been determined by analysing spectroscopic and photometric data with the program PHOEBE. A total of 241 flares have been detected in the photometric data and for 190 flares, which light curves were not affected by eclipses, released energies were estimated. The set of flares was used for the study of stellar activity of the binary. The energy distribution of observed flares is similar to the flares observed on other flare stars and also on the Sun. This suggests, that the flare mechanism is the same for these stars.
Recruitment in a non-profit organization.
Steklá, Veronika ; Stříteský, Marek (advisor) ; Wolf, Marek (referee)
The main objective of this thesis is to create a proposal for improving recruitment campaign for AIESEC Prague based on research. The thesis is divided into two parts, a theoretical and a practical part. The theoretical part defines necessary terminology. The introduction of the practical part explains the fundamentals and the structure of AIESEC, both from an international perspective and Czech republic perspective. The practical part continues with an evaluation of a survey, which consists of three questionnaires. The evaluation is divided into six individual subchapters. The results of the survey are complemented by a list of other student organisations that are potential competitors. This is followed with evaluation of AIESECs position in the student organisations market in terms of strenghts, weaknesses, potential opportuities and threats. The conclusion summarizes and proposes further improvements to the recruitment proces.
CCD photometry of variable objects in nearby galaxies
Kára, Jan ; Wolf, Marek (advisor) ; Zasche, Petr (referee)
The work concerns the study of variable stars in the Small Magellanic Cloud with use of time series of photometric images of star field NGC 330, which were obtained by the 1,54-m Danish telescope at the observatory La Silla in Chile during years 2012 - 2016. The aim of this work is to produce light curves of variable stars a to determine their period of variability assuming the variations are periodical. For some stars data from earlier published papers were used, which led to the coverage of longer period of time and therefore to the improvement of the accuracy of the period determination. The work lists summary of some of the types of variable stars and of mechanisms causing their variability. The work focus mainly on cepheids, which can be used to determine distances in the Universe thanks to the relation between their absolute magnitude and period of pulsation.
The light curves of eclipsing binaries
Korda, David ; Zasche, Petr (advisor) ; Wolf, Marek (referee)
New CCD photometric observations of ten short-period LMB (Low Mass Binaries) were carried out. Data were obtained using 65 cm telescope in Ondřejov in the filters I, R and V from 2014 to 2016. Light curves were analysed using the program PHOEBE. The obtained masses and radii of the stars were compared with the theoretical mass-radii relation. There arises that the short-period binaries have the radii of about 4 % larger than the theoretical prediction from the stellar evolution models. Powered by TCPDF (
Pulsating components in binaries
Korda, David ; Zasche, Petr (advisor) ; Wolf, Marek (referee)
In the beginning there are introduced the binaries and pulsating stars. The main aim of the present work was the study of Delta Scuti stars within the eclipsing binaries. In particular, observing the stellar system V389 Cas at Ondrejov observatory, reduction of the CCD images with the program MuniWin, and analysis of the light curve with program Phoebe. From the residuals of the light curve there were studied the pulsations by the program Period04, resulting in its pulsational period. The relation between both periods - orbital and pulsational - was studied by means of the already known systems, including the theoretical relation and location of the star V389 Cas in the period-period diagram. 1
Selected gravitational effects in the Universe
Franc, Tomáš ; Wolf, Marek (advisor) ; Randa, Miroslav (referee) ; Štefl, Vladimír (referee)
Title: Selected gravitational effects in the Universe Author: Mgr. Tomáš Franc Department: Astronomical Institute of Charles University Supervisor: doc. RNDr. Marek Wolf, CSc., Astronomical Institute of Charles University Abstract: In this Thesis we have given an overview of tidal phenomena with their explanations and also explained the gravitational assist with examples of its use. We have created many pictures and 17 animations for better understanding of these topics. This part of the Thesis is focused on high school students and their teachers, it can be used by teachers for their inspiration for lessons, or students and more generally people interested in these topics can read this part as a study text. The main part of the Thesis is the result of research conducted on 13 high schools in the Czech Republic. 800 students took part in the research; its purpose was to find out students' knowledge of tidal phenomena and the gravitational assist. The research was carried out in the form of questionnaires. Keywords: gravity, tidal phenomena, gravitational assist, pedagogical research
The application of the LSST in the physics of the small solar-system bodies
Sváda, Petr ; Brož, Miroslav (advisor) ; Wolf, Marek (referee)
This thesis is devoted to the description of the Large Synoptics Survey Telescope (LSST) and its use in the physics of small solar-system bodies. Based on the telescope optics parameters and the theory of signal and noise we calculate limiting magnitude of the LSST (24,9 0,4) mag (in the V band). This value, together with data from MPC and WISE databases, serve as an input parameter for the calculation of the minimum diameter ( ) m of a main-belt asteroid, that LSST will be able to observe. We also estimated that (160 ± 118) million asteroids could be observable by the LSST. Taking into account the planned observational strategy and cadence, we calculated that a sufficiently bright asteroid will be observed approximately 370 times. Finally, the possible applications of the LSST are discussed: e. g. a development of collisional models, explanation of orbital and rotational dynamics of sub-kilometer objects.
The light-curve solution of an eclipsing binary
Procházka, Ondřej ; Zasche, Petr (advisor) ; Wolf, Marek (referee)
The main aim of this work was the first detailed analysis of an eclipsing binary system V641 Aur. The complete light curve of this binary was obtained in three photometric filters, which were analyzed with the program PHOEBE. It is a double star with the orbital period of about 0.50487 day, whose both components are rather similar. Their individual spectral types are probably F6 and F8 (according to the temperatures), or F6 and F6 (as derived from masses). Both are orbiting on a circular orbit and despite their short period the system is a detached one and both components are still located on the main sequence. Moreover, thanks to the asymmetry of the light curve there was discovered a spot on the surface of the primary component, and the third light was not detected. For more detailed analysis higher accuracy of photometry and spectroscopy data are required.
Photometric study of dwarf nova EX Dra
Pilarčík, Lukáš ; Wolf, Marek (advisor) ; Mayer, Pavel (referee)
Photometry of eclipsing dwarf-nova EX Draconis was performed at the observatory of Astronomical Institute of the Academy of Sciences of the Czech Republic in Ondřejov and at the Astronomical Observatory on Kolonické sedlo during 63 nights. I calculated times of minimum light by two methods - the mirror method and the derivative method. The mirror method is more precise for these measurements with longer exposure time and smaller coverage of the light curve of eclipse. 53 new times of minima calculated by the mirror method and times of minima obtained from the older articles about EX Dra were included in the O-C diagram and fitted by the sine function and theoretical curve of LITE caused by an unseen third body. Period of cyclic changes for the sine function is 25 years, instead of 4 or 5 years period given in older papers.Period of the third body orbit is aproximately 17 years and its minimum mass is 53.5 Jupiter's mass. The sum of squared deviations is 5 times smaller for the LITE, which means that the LITE ilustrates the O-C diagram better. I determined the average outburst period for three observational seasons and I drew the phase curve of outburst. Finally, I calculated the short period of the light changes outside eclipse.

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See also: similar author names
2 Wolf, Martin
2 Wolf, Michal
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