WD2 - Origin and physics of Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars |
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Speaker |
Arbañil, José |
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Coauthors |
Carvalho,Geanderson A.; Marinho Jr, Rubens M.; Malheiro, Manuel |
| Talk Title |
Surface Electrical Charge Distribution In White Dwarfs |
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Abstract |
We study the equilibrium configuration and the radial stability of white dwarfs composed of charged perfect fluid, analyzing through the results obtained from the solution of the hydrostatic equilibrium equation, which is altered from its original form to add the electrical part. We regard that the fluid pressure and the fluid energy density follow the relation of a fully degenerate electron gas. For the electric charge distribution in the object, we consider that it is centralized only close to the white dwarfs' surfaces. We obtain larger and more massive white dwarfs when the total electric charge is increased. To appreciate the effects of the electric charge in the structure of the star, we found that it must be $\sim10^{20}[\rm C]$ with which the electric field is $\sim10^{16}[\rm V/cm]$, being mostly smaller than the Schwinger limit. For white dwarfs with electric fields close to this limit, we obtain that these have masses of $\sim2M_{\odot}$. We also found that in a system constituted by fixed charged static equilibrium configurations, the maximum mass point found on it marks the onset of the instability. |
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