Light curves analysis of four W Uma-type stars

العناوين الأخرى

تحليل المنحنيات الضوئية لأربع نجوم من كوكبة الدب الأكبر

مقدم أطروحة جامعية

Nahi, Nimah Abd Allah

مشرف أطروحة جامعية

Laftah, Salih Jasim

أعضاء اللجنة

Salih, Salah A.
al-Abbudi, Bushra Qasim
Ahmad, Muhammad S.

الجامعة

جامعة بغداد

الكلية

كلية العلوم

القسم الأكاديمي

قسم الفلك و الفضاء

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2011

الملخص الإنجليزي

W Ursae Majoris stars are easily recognized by their light curves with near equal minima and by their continuous light variation.

In general, the periods of these systems are typically short and range between (0.2 day to around 0.7 day) and mass ratio (0.072-1).

Each of the components in the binary system is of nearly the same spectral type, from around middle A to early K, with the huge part concentrated in middle F through early G.

The stars are assumed to be in a similar evolutionary state, located near or just above the zero age main sequence .

In this work, the systems (W UMa, V839 Oph, V566 Oph in both blue and yellow filters and VW Cep in yellow filter only) have been chosen.

The light curve for each system analysed separately using Kopal’s method which is based on Fourier transforms in frequency domain.

The observations which represent the primary and the secondary minima for each system are used to calculate the moment areas and Fourier coefficients, from these moment areas, the light curve elements which are the fractional radii, the fractional luminosities and the inclination angle are determined.

The results have been compared with previous studies, and our results indicated that the selected systems are contact systems

التخصصات الرئيسية

الفلك و علومه

عدد الصفحات

80

قائمة المحتويات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-603884