Alignment Timescale of the Microquasar GRO J1655-40

Understand

The microquasar GRO J1655-40 has a black hole with spin angular momentum apparently misaligned to the orbital plane of its companion star.

• We analytically model the system with a steady state disc warped by Lense-Thirring precession and find the timescale for the alignment of the black hole with the binary orbit.
• We make detailed stellar evolution models so as to estimate the accretion rate and the lifetime of the system in this state.
• The secondary can be evolving at the end of the main sequence or across the Hertzsprung gap.