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arXiv · 1001.0359

Circular Orbits in Extremal Reissner Nordstrom Spacetimes

Parthapratim Pradhan·Parthasarathi Majumdar
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Abstract

Circular null geodesic orbits, in extremal Reissner-Nordstrom spacetimes, are examined with regard to their stability, and compared with similar orbits in the near-extremal situation. Extremization of the effective potential for null circular orbits shows the existence of a stable circular geodesic in the extremal spacetime, precisely {\it on} the event horizon, which coincides with its null geodesic generator. Such an orbit also emerges as a global minimum of the effective potential for circular {\it timelike} orbits. This type of geodesic is of course absent in the corresponding near-extremal spacetime, as we show here, testifying to differences between the extremal limit of a generic RN spacetime and the exactly extremal geometry.

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Parthapratim Pradhan, Parthasarathi Majumdar. 2010-01-03. Circular Orbits in Extremal Reissner Nordstrom Spacetimes. https://doi.org/10.1016/j.physleta.2010.11.015

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