2010/09/20 by Elena D'Onghia, Mark Vogelsberger, Claude-Andre Faucher-Giguere +2 · 1 citation
Engineering · Physics and Astronomy · #Gravitation #Impulse (physics) #Perturbation (astronomy) #Pulsars and Gravitational Waves Research #Spacecraft Dynamics and Control #Spinning #Stars #Stellar, planetary, and galactic studies #Tidal acceleration #Tidal force #Transient (computer programming) #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/725/1/353
22 pages, 13 figures, ApJ submitted, numerical routines for evaluation of special functions and analytical results are provided upon request
arxiv created 2010/09/20 · openalex publication_date 2010/11/18 · arxiv updated 2015/05/20 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
When a spinning system experiences a transient gravitational encounter with an external perturber, a quasi-resonance occurs if the spin frequency of the victim roughly matches the peak angular speed of the perturber. Such encounters are responsible for the formation of long tails and bridges during galaxy collisions. For high-speed encounters, the resulting velocity perturbations can be described by the impulse approximation. The traditional impulse approximation, however, does not distinguish between prograde and retrograde encounters, and therefore completely misses the resonant response. Here, we modify the impulse approximation to include the effects of quasi-resonant phenomena on stars orbiting within a disk. Explicit expressions are derived for the velocity and energy changes to the stars induced by tidal forces from an external gravitational perturber passing either on a straight line or a parabolic orbit. Comparisons with numerical-restricted three-body calculations illustrate the applicability of our analysis.