Events Daily

Tuesday, April 18, 2023

Astro Journal Club
Event Type: Other
Time: 12:30 PM - 1:30 PM
Location: 726 Broadway, 940, CCPP Seminar

Orbital Evolution of Binaries in Circumbinary Disks
Magdalena Siwek, Harvard University
Event Type: Astro Seminar
Time: 2:00 PM - 3:15 PM
Location: 726 Broadway, 940, CCPP Seminar
Abstract: I will present the to-date largest parameter space exploration of multi-scale binaries in circumbinary disks (CBDs), deriving orbital evolution prescriptions for eccentric, unequal mass binaries from a suite of 2D hydrodynamic simulations run with Arepo. I will show that binary eccentricities evolve towards steady state values that increase with mass ratio, and saturate at an equilibrium eccentricity e_{b,eq} ~ 0.5 in the large mass ratio regime. This result is in line with resonant theory. For binaries accreting at their combined Eddington limit, a steady state eccentricity can be achieved within a few Megayears. Once at their steady state eccentricities, binaries with mass ratios greater than q_b > 0.3 evolve towards coalescence, while lower mass ratio systems expand due to CBD torques. I will discuss implications for population studies of massive black hole binaries, protostars in binary systems, and post-common envelope binaries observed by ground-based gravitational wave detectors.

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