Innermost stable circular orbit

The Innermost stable circular orbit (often called the ISCO) is the smallest orbit in which a test particle can stably orbit a massive object in general relativity.^[1] The location of the ISCO, the ISCO-radius (), depends on the angular momentum (spin) of the central object. For a non-spinning object, a where the gravitational field can be expressed with the Schwarzschild metric, the ISCO is located at,

As the angular momentum of the central object increases, decreases. Even for a non-spinning object, the ISCO radius is only three times the Schwarzschild radius, suggesting that only black holes have innermost stable circular orbits outside of their surfaces.

References

• Misner, Charles; Thorne, Kip S.; Wheeler, John (1973). Gravitation. W. H. Freeman and Company. ISBN 0-7167-0344-0. 

External links

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