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| en:praktikum:wrstern [2016/10/08 23:49] – [Fit the spectrum] rhainich | en:praktikum:wrstern [2024/10/09 08:09] (current) – Adjusts name of laboratory computer rhainich |
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| Find the [[http://www.astro.physik.uni-potsdam.de/PoWR.html|grid models]] at the main page of the [[http://www.astro.physik.uni-potsdam.de|Astrophysics Department of the Uni Potsdam]]. Get an impression of the parameters that enter into the models, e.g. the range of temperatures and the so called transformed radius $R_{\mathrm{t}}$. Learn the principles of line-driven winds. | Find the [[http://www.astro.physik.uni-potsdam.de/PoWR.html|grid models]] at the main page of the [[http://www.astro.physik.uni-potsdam.de|Astrophysics Department of the Uni Potsdam]]. Get an impression of the parameters that enter into the models, e.g. the range of temperatures and the so called transformed radius $R_{\mathrm{t}}$. Learn the principles of line-driven winds. |
| Then copy the //WRplot// script ''lmcstars.plot'' and the accompanying file for the line identifications ''ident.dat'' from the directory ''~/scripts/d3/'' into your working directory on the laboratory course computer ''a12''. | Then copy the //WRplot// script ''lmcstars.plot'' and the accompanying file for the line identifications ''ident.dat'' from the directory ''~/scripts/d3/'' into your working directory on the laboratory course computer ''columba''. |
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| ===== Realization ===== | ===== Realization ===== |
| ==== Determine the stellar parameters ==== | ==== Determine the stellar parameters ==== |
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| The stellar parameters can be obtained from the information of the selected model. These parameters are described on the PoWR homepage. Following the Stefan-Boltzmann law: | The stellar parameters can be obtained from the properties of the selected model. These parameters are described on the PoWR homepage. Following the Stefan-Boltzmann law: |
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| $L \propto R_{*}^2$ and $L \propto T^4$, | $L \propto R_{*}^2$ and $L \propto T^4$, |
| $L \propto R_{*}^2 \cdot T^4$. | $L \propto R_{*}^2 \cdot T^4$. |
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| The stellar radius (at constant luminosity) is proportional to $T^{−2}$. By adding the ''shift'' parameter to the luminosity the true luminosity can be customized for a star. | The stellar radius (at constant luminosity) is proportional to $T^{−2}$. By adding the ''shift'' parameter to the luminosity, the model luminosity can be adjusted to the true luminosity of a star. |
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| The mass loss rate is connected to the luminosity via the transformed radius: | The mass loss rate is connected to the luminosity via the transformed radius: |
| $\dot{M}^{\frac{2}{3}} \propto T^{−2} \cdot R_t$. | $\dot{M}^{\frac{2}{3}} \propto T^{−2} \cdot R_t$. |
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| ===== Protocol ===== | ===== Report ===== |
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| A usual laboratory course protocol is to be handed in. | A usual laboratory course report is to be handed in. |
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| [[en:praktikum:index|Overview: Laboratory Courses]] | [[en:praktikum:index|Overview: Laboratory Courses]] |