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| SPAT0006-1 | Stellar atmospheres
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| Duration : | 20h Th, 10h Pr |
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| Credits/ECTS : |
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| Holder(s) : | Grégor Rauw |
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| Language : | Langue française |
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| Course contents : | 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. |
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| Course objective : | 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 different effects that determine the aspect of spectral lines (intrinsic width, broadening, rotational velocity, chemical composition). Finally, the main classification criteria that are used to assign a spectral type directly from the observations are presented. |
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| Prerequisites : | Good knowledge of physics (atomic spectroscopy) and mathematics. |
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| Workshops : | Several hands-on sessions are organized to illustrate the concepts introduced during the lectures. |
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| Organization : | 20 hours of lectures + 10 hours of hands-on sessions including some computer labs (use of a computer code to determine the rotational velocity of a star). |
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| Written notes : | The lecture notes are provided in English. |
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| Assessment : | The assessment will be done based on an oral exam. |
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| Contacts : | Gregor Rauw
Chercheur Qualifié FNRS
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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| Remarks : | N/A |
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