Existence and Stability of Circular Orbits in a Schwarzschild Field with Nonvanishing Cosmological Constant

Abstract

The Schwarzschild metric with A > 0 allows circular orbits only within the annular region 3m < ro < (3m/A)-t. For m < tA --t this region includes a narrower annular zone, throughout which circular orbits are stable but outside of which they are unstable.