Harris, G.J.;
Lynas-Gray, A.E.;
Miller, S.;
Tennyson, J.;
(2004)
The role of HeH+ in cool helium rich white dwarfs.
The Astrophysical Journal
, 617
(2, Par)
L143-L146.
10.1086/427391.
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Abstract
HeH+ is found to be the dominant positive ion over a wide range of temperatures and densities relevant to helium-rich white dwarfs. The inclusion of HeH+ in ionization equilibrium computations increases the abundance of free electrons by a significant factor. For temperatures below 8000 K, He- free-free absorption is increased by up to a factor of 5 by the inclusion of HeH+. Illustrative model atmospheres and spectral energy distributions are computed, which show that HeH+ has a strong effect on the density and pressure structure of helium-rich white dwarfs with Teff < 8000 K. The inclusion of HeH+ significantly reddens spectral energy distributions and broadband color indices for models with Teff < 5500 K. This has serious implications for existing model atmospheres, synthetic spectra, and cooling curves for helium-rich white dwarfs.
| Type: | Article |
|---|---|
| Title: | The role of HeH+ in cool helium rich white dwarfs |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1086/427391 |
| Publisher version: | http://dx.doi.org/10.1086/427391 |
| Language: | English |
| Keywords: | equation of state, stars: atmospheres, white dwarfs |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1318 |
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