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| SPAT0006-1 | Stellar atmospheres
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| Duration : | 20h Th, 10h Pr |
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| Number of credits : |
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| Lecturer : | Grégor Rauw |
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Language(s) of instruction :
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| French language |
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Organisation and examination :
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| Teaching in the second semester |
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Course contents :
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| Stellar spectra are formed in the stellar atmospheres and they contain a wealth of information on the physical conditions in these atmospheres. The goal of this course is to establish the link between the physical parameters on the one hand and the observable quantities (i.e. the spectra) on the other hand.
The course starts by reviewing the link between the Hertzsprung-Russell diagram and the stellar spectra. We then recall the fundamental notions of the interaction between matter and radiation and we introduce the concept of radiative transfer both in static and moving atmospheres. Stellar atmosphere codes aiming at the calculation of synthetic spectra rely on a number of assumptions (hydrostatic equilibrium, local thermodynamical equilibrium or absence of the latter) and we discuss these different hypotheses. We then review the various effects that determine the aspect of spectral lines (intrinsic width, Doppler and pressure broadening, rotational velocity, chemical composition). The modeling of expanding atmospheres (stellar winds) is also addressed. Finally, the main classification criteria that are used to assign a spectral type directly from the observations are presented. |
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Learning outcomes of the course :
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| The purpose of this course is to explain the link between physical parameters of the stars and the characteristics of their spectra. Upon completion of this course the students will be able to understand how stellar properties such as the temperature, the luminosity, the chemical composition,... can be inferred from the analysis of stellar spectra. |
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Prerequisites and co-requisites/ Recommended optional programme components :
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| Good knowledge of physics (atomic spectroscopy) and mathematics. |
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Planned learning activities and teaching methods :
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| Several hands-on sessions are organized to illustrate the concepts introduced during the lectures. |
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Mode of delivery (face-to-face ; distance-learning) :
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| 20 hours of lectures + 10 hours of hands-on sessions possibly including some computer labs (use of a computer code to determine the rotational velocity of a star).
The course will take place during the second semester. |
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Recommended or required readings :
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| The lecture notes are provided in English through a pdf file that is freely available. |
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Assessment methods and criteria :
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| The evaluation emphasizes the understanding of the course and the ability to use the techniques that have been taught. To successfully pass the exam students have to learn and understand. The assessment will be done based on a written exam consisting of theory questions and exercises. |
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Work placement(s) :
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Organizational remarks :
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| N/A |
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Contacts :
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| Gregor Rauw
Chargé de Cours
Institut d'Astrophysique et Géophysique, Bât. B5c,
Allée du 6 Août, 17
4000 Liège
Tel. +32-(0)4 366 9740
e-mail: rauw@astro.ulg.ac.be |
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| Items online : |
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| Lecture notes |
| Lecture notes in English and copies of the slides in French. |
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