Spectral investigation of the interstellar extinction curve

Other Title(s)

تحقيق طيفي لمنحني الاعتتام للمادة ما بين النجوم

Dissertant

Husayn, Haydar Rida

Thesis advisor

Jumah, Nazim Hasan Haydar
Karim, Layth Mahmud

Comitee Members

Abbud, Kamal Muhammad
al-Rikabi, Ali Talib Muhammad Hasan
Salih, Muhammad A. B.

University

University of Baghdad

Faculty

College of Science

Department

Astronomy and Space Department

University Country

Iraq

Degree

Master

Degree Date

2013

English Abstract

The aim of this work is to explain the nature of the interstellar matter, investigating the interstellar extinction curve by determining the molecules mixtures thought to be responsible for the absorption features in the wavelength range (8.5-12.5) μm and trying to prove that this mixture is probably composed of organic or inorganic materials or a mixture of them.

The chemical reaction in the interstellar matter and the formation of the molecules have taken a considerable attention in order to understand the mechanism of physical condition led to the formation of chemical compounds that responsible for the absorption features in the wavelength range (8.5-12.5) μm.

Laboratory samples were prepared for different organic and inorganic materials and then the transmittance is measured for each sample as a function of a wave number (1/cm) using FTIR spectrophotometer.

The transmittance values as a function of wave number are transformed to flux density as a function of wavelength (μm) using Beer– Lambert law’s and Planck’s function .This process enabled us to have freedom in preparing the models.

Many attempts have been done for preparing the model by changing the materials in the desired mixture as well as their weight ratios seeking best fitting with observation data of trapezium Nebula.

Six preparing sample models have been examined using the old technique (flux summation procedure) and four models also examined using our new approach (flux convolution procedure).The results indicate that the convolution approach (new procedure) show higher cross correlation coefficients.

This indicates the superiority of the new suggested approach

Main Subjects

Astronomy

No. of Pages

117

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-604223