Conservative corrections to the innermost stable circular orbit (ISCO) of a Kerr black hole: A new gauge-invariant post-Newtonian ISCO condition, and the ISCO shift due to test-particle spin and the gravitational self-force

Journal Article · Sat Jan 15 00:00:00 EST 2011 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.83.024028· OSTI ID:21503968

Favata, Marc ^[1]

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1. Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, California 91109 (United States) and Theoretical Astrophysics, 350-17, California Institute of Technology, Pasadena, California 91125 (United States)

The innermost stable circular orbit (ISCO) delimits the transition from circular orbits to those that plunge into a black hole. In the test-mass limit, well-defined ISCO conditions exist for the Kerr and Schwarzschild spacetimes. In the finite-mass case, there are a large variety of ways to define an ISCO in a post-Newtonian (PN) context. Here I generalize the gauge-invariant ISCO condition of Blanchet and Iyer [Classical Quantum Gravity 20, 755 (2003)] to the case of spinning (nonprecessing) binaries. The Blanchet-Iyer ISCO condition has two desirable and unexpected properties: (1) it exactly reproduces the Schwarzschild ISCO in the test-mass limit, and (2) it accurately approximates the recently calculated shift in the Schwarzschild ISCO frequency due to the conservative-piece of the gravitational self-force [L. Barack and N. Sago, Phys. Rev. Lett. 102, 191101 (2009)]. The generalization of this ISCO condition to spinning binaries has the property that it also exactly reproduces the Kerr ISCO in the test-mass limit (up to the order at which PN spin corrections are currently known). The shift in the ISCO due to the spin of the test-particle is also calculated. Remarkably, the gauge-invariant PN ISCO condition exactly reproduces the ISCO shift predicted by the Papapetrou equations for a fully relativistic spinning particle. It is surprising that an analysis of the stability of the standard PN equations of motion is able (without any form of 'resummation') to accurately describe strong-field effects of the Kerr spacetime. The ISCO frequency shift due to the conservative self-force in Kerr is also calculated from this new ISCO condition, as well as from the effective-one-body Hamiltonian of Barausse and Buonanno [Phys. Rev. D 81, 084024 (2010)]. These results serve as a useful point of comparison for future gravitational self-force calculations in the Kerr spacetime.

• OSTI ID: 21503968
• Journal Information: Physical Review. D, Particles Fields, Vol. 83, Issue 2; Other Information: DOI: 10.1103/PhysRevD.83.024028; (c) 2011 American Institute of Physics; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
APPROXIMATIONS
BLACK HOLES
COMPARATIVE EVALUATIONS
CORRECTIONS
EQUATIONS OF MOTION
GAUGE INVARIANCE
HAMILTONIANS
KERR METRIC
MASS
ORBITS
PARTICLES
QUANTUM GRAVITY
RELATIVISTIC RANGE
SCHWARZSCHILD METRIC
SPACE-TIME
SPIN
STABILITY
TEST PARTICLES
ANGULAR MOMENTUM
CALCULATION METHODS
DIFFERENTIAL EQUATIONS
ENERGY RANGE
EQUATIONS
EVALUATION
FIELD THEORIES
INVARIANCE PRINCIPLES
MATHEMATICAL OPERATORS
METRICS
PARTIAL DIFFERENTIAL EQUATIONS
PARTICLE PROPERTIES
QUANTUM FIELD THEORY
QUANTUM OPERATORS