Tidal disruption of planetary bodies by white dwarfs I: A hybrid SPH-analytical approach

TL;DR

This paper presents a hybrid simulation method combining SPH and analytical techniques to efficiently model the long-term tidal disruption of planetary bodies by white dwarfs, overcoming previous computational limitations.

Contribution

The authors develop and validate a novel hybrid SPH-analytical approach that accurately simulates tidal disruptions over extended periods with reduced computational cost.

Findings

Hybrid model matches full SPH simulations in results

Significantly faster than traditional SPH-only methods

Enables long-term evolution studies of tidal debris

Abstract

We introduce a new hybrid method to perform high-resolution tidal disruption simulations, at arbitrary orbits. An SPH code is used to simulate tidal disruptions only in the immediate spatial domain of the star, namely, where the tidal forces dominate over gravity, and then during the fragmentation phase in which the emerging tidal stream may collapse under its own gravity to form fragments. Following each hydrodynamical simulation, an analytical treatment is then applied to instantaneously transfer each fragment back to the tidal sphere for its subsequent disruption, in an iterative process. We validate the hybrid model by comparing it to both an analytical impulse approximation model of single tidal disruptions, as well as full-scale SPH simulations spanning the entire disc formation. The hybrid simulations are essentially indistinguishable from the full-scale SPH simulations, while computationally outperforming their counterparts by orders of magnitude. Thereby our new hybrid approach uniquely enables us to follow the long-term formation and continuous tidal disruption of the planet/planetesimal debris, without the resolution and orbital configuration limitation of previous studies. In addition, we describe a variety of future directions and applications for our hybrid model, which is in principle applicable to any star, not merely white dwarfs