Stuttgart 2012 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 15: Poster: Theorie/Modellierung

P 15.4: Poster

Mittwoch, 14. März 2012, 16:30–19:00, Poster.III

Modeling Brown Dwarfs using an ab initio equation of state for hydrogen — Andreas Becker, •Nadine Nettelmann, and Ronald Redmer — Universität Rostock

Models of the interior of Giant Planets and Brown Dwarfs rely on the equation of state (EOS) data for hydrogen, helium and water, as a representative of all heavier elements, which have usually considerable uncertainties in the high-pressure domain. We constructed a wide range EOS for hydrogen that consists of fluid variational theory data [1] for the low-density range (rho<0.2g/ccm), EOS data derived from finite-temperature density functional theory molecular dynamics (FT-DFT-MD) [2] for the intermediate densities (0.2g/ccm < rho <70 g/ccm) and the Chabrier-Potekhin model for the high densities (rho > 70 g/ccm) [3]. FT-DFT-MD methods are able to treat the exchange and correlation effects in correlated systems very accurate in such a way that the data reproduce the high-pressure experiments very well, e.g. [2,4,5]. Using these high quality data we model Brown Dwarfs in a fully convective one-layer model. We obtain interior structure profiles and mass-radius relationships and compare our results with those derived using the Saumon-Chabrier-van Horn EOS [6].

References: [1] Holst, B. et al. 2007: Contr. Plasma Phys. 47, 368. [2] Holst, B. et al. 2008: Phys. Rev. B 77, 184201. [3] Potekhin. A.Y., Chabrier, G., 2000: Phys. Rev. E 62, 8554. [4] French, M. et al. 2009: Phys. Rev. B 79, 054107. [5] Caillabet, L. et al. 2011: Phys. Rev. B 83, 094101. [6] Saumon, D. et al. 1995: Astrophys. J. Suppl. Ser. 99, 713.