Sökning: onr:"swepub:oai:DiVA.org:kth-160417" > Near-polytropic ste...
Fältnamn | Indikatorer | Metadata |
---|---|---|
000 | 04183naa a2200409 4500 | |
001 | oai:DiVA.org:kth-160417 | |
003 | SwePub | |
008 | 150219s2014 | |||||||||||000 ||eng| | |
009 | oai:DiVA.org:su-114278 | |
024 | 7 | a https://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1604172 URI |
024 | 7 | a https://doi.org/10.1051/0004-6361/2013224612 DOI |
024 | 7 | a https://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1142782 URI |
040 | a (SwePub)kthd (SwePub)su | |
041 | a engb eng | |
042 | 9 SwePub | |
072 | 7 | a ref2 swepub-contenttype |
072 | 7 | a art2 swepub-publicationtype |
100 | 1 | a Barekat, Atefehu Stockholms universitet,KTH,Nordic Institute for Theoretical Physics NORDITA,Department of Astronomy, AlbaNova University Center, Stockholm University, Stockholm, Sweden,Nordiska institutet för teoretisk fysik (Nordita),Institutionen för astronomi,Max-Planck-Institut für Sonnensystemforschung, Germany4 aut0 (Swepub:su)atba5227 |
245 | 1 0 | a Near-polytropic stellar simulations with a radiative surface |
264 | c 2014-11-13 | |
264 | 1 | b EDP Sciences,c 2014 |
338 | a print2 rdacarrier | |
500 | a QC 20150223 | |
500 | a AuthorCount:2; | |
520 | a Context. Studies of solar and stellar convection often employ simple polytropic setups using the diffusion approximation instead of solving the proper radiative transfer equation. This allows one to control separately the polytropic index of the hydrostatic reference solution, the temperature contrast between top and bottom, and the Rayleigh and Peclet numbers. Aims. Here we extend such studies by including radiative transfer in the gray approximation using a Kramers-like opacity with freely adjustable coefficients. We study the properties of such models and compare them with results from the diffusion approximation. Methods. We use the Pencil code, which is a high-order finite difference code where radiation is treated using the method of long characteristics. The source function is given by the Planck function. The opacity is written as kappa = kappa(0)rho T-a(b), where a = 1 in most cases, b is varied from -3.5 to +5, and kappa(0) is varied by four orders of magnitude. We adopt a perfect monatomic gas. We consider sets of one-dimensional models and perform a comparison with the diffusion approximation in one-and two-dimensional models. Results. Except for the case where b = 5, we find one-dimensional hydrostatic equilibria with a nearly polytropic stratification and a polytropic index close to n = (3 -b)/(1 + a), covering both convectively stable (n > 3/2) and unstable (n < 3/2) cases. For b = 3 and a = -1, the value of n is undefined a priori and the actual value of n depends then on the depth of the domain. For large values of kappa(0), the thermal adjustment time becomes long, the Peclet and Rayleigh numbers become large, and the temperature contrast increases and is thus no longer an independent input parameter, unless the Stefan-Boltzmann constant is considered adjustable. Conclusions. Proper radiative transfer with Kramers-like opacities provides a useful tool for studying stratified layers with a radiative surface in ways that are more physical than what is possible with polytropic models using the diffusion approximation. | |
650 | 7 | a NATURVETENSKAPx Fysikx Astronomi, astrofysik och kosmologi0 (SwePub)103052 hsv//swe |
650 | 7 | a NATURAL SCIENCESx Physical Sciencesx Astronomy, Astrophysics and Cosmology0 (SwePub)103052 hsv//eng |
653 | a radiative transfer | |
653 | a hydrodynamics | |
653 | a Sun: atmosphere | |
700 | 1 | a Brandenburg, Axelu Stockholms universitet,Nordiska institutet för teoretisk fysik (Nordita),Institutionen för astronomi4 aut0 (Swepub:su)brandenb |
710 | 2 | a KTHb Nordic Institute for Theoretical Physics NORDITA4 org |
773 | 0 | t Astronomy and Astrophysicsd : EDP Sciencesg 571, s. A68-q 571<A68-x 0004-6361x 1432-0746 |
856 | 4 | u https://www.aanda.org/articles/aa/pdf/2014/11/aa22461-13.pdf |
856 | 4 8 | u https://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160417 |
856 | 4 8 | u https://doi.org/10.1051/0004-6361/201322461 |
856 | 4 8 | u https://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-114278 |
Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.