The empirical mass-luminosity relation in the galactic cluster Hyades

Mesarić, Martina (2014) The empirical mass-luminosity relation in the galactic cluster Hyades. Diploma thesis, Faculty of Science > Department of Physics.

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Abstract

Galactic open clusters are important for studying structure and evolution of stars. Stars in a cluster were formed from the same molecular cloud; hence they have very similar chemical composition and approximately the same age. Members of a cluster differ by their mass, which is tightly bound with other stellar parameters. Mass is the main property that determines the evolutionary path of a star, its main sequence lifetime and a final stage of the evolution. Stellar mass can be measured directly only in binary or multiple systems. Binary stars are gravitationally bound systems of two components orbiting around their common center of mass. The most valuable are the eclipsing spectroscopic binaries, for which the spectral lines from both stars are visible in their spectrum. From spectroscopic and photometric analysis of such a system, it is possible to calculate masses, radii and luminosities with great accuracy. In this work, the spectroscopic and photometric measurements of the binary system V818 Tau in Hyades star cluster are analyzed. The method of spectral disentangling is used in spectroscopic analysis, which enables separation of the individual spectra of the component stars from a time series of composite spectra, simultaneously deriving the system orbital elements. In turn, the spectral analysis gives the atmospheric parameters of both stars: effective temperatures, metallicity and rotational velocities. In combination with the light curve analysis the masses, radii and luminosities can be determined. The Wilson-Devinney code is used for light curve modeling, which implements Roche geometry and a detailed treatment of reflection and other physical effects. V818 Tau is only eclipsing binary system in Hyades. Therefore is extremely important in anchoring the mass-luminosity relation for Hyades. In this work, the mass-luminosity relation is deduced from 10 stars, besides the components of V818 Tau another 4 interferometric binary stars were used.

Item Type: Thesis (Diploma thesis)
Keywords: star clusters, equations of stellar structure, binary stars, Wilson-Devinney method, Hyades
Supervisor: Pavlovski, Krešimir
Date: 18 April 2014
Number of Pages: 64
Subjects: NATURAL SCIENCES > Physics > Astronomy and Astrophysics
Divisions: Faculty of Science > Department of Physics
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 30 May 2014 13:15
Last Modified: 06 Sep 2016 16:02
URI: http://digre.pmf.unizg.hr/id/eprint/2021

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