Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

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Measurement of Stellar Temperatures From Spectral Line-Depth Ratıo : A Calibration Study

Precise effective temperatures are needed for determination of several parameters of stars. In this study, line depth ratio (LDR) method was applied to the spectra taken at Okayama Astrophysical Observatory (OAO) for the determination of effective temperature.

High resolution (R~70000) echelle spectra taken from OAO online archive, obtained by using HIDES (High Dispersion Echelle Spectrograph) at the coude focus of the at the 1.88 m telescope of OAO in the wavelength region (“G”) 5000-6200 Å and (“R”) 5800-7000 Å were used for 160 late F, G and early K type dwarfs and subgiants of the solar neighborhood. 20 line pairs were selected for LDR method and spectral line depths were measured by some of the external packages in IRAF (Image Reduction and Analysis Facility). Each line depth ratios were plotted against effective temperatures and only those pairs of lines that showed tight correlation were retained. 15 best calibrations showing the least scatter were adopted.

As a result of this study, it is shown that LDR method can be used to determine precise effective temperatures of stars with an uncertainty of ±16-23 K from OAO spectra and the expectance of LDR method for determining effective temperature has been discussed.

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