Fragmentation Dynamics of Pristine Interstellar Comets: An Exploratory Multi-Physics Simulation Study
Abstract
We present an exploratory numerical model for the thermal evolution and fragmentation of pristine interstellar comets on a first passage through the inner Solar System, applied over a grid of perihelion distances (q=0.25--$1.5$~AU) and tensile strengths (σt=50--$500$~Pa). A single nucleus (M0=2×1012~kg, R0≈1.06~km, dust/ice =1, ices 35\% CO, 30\% CO2, 15\% CH4, 20\% H2O) follows a hyperbolic trajectory from an initially 30~K state, with heat conduction, energy-balanced multi-species sublimation, dust lifting and lag-mantle growth, and a subsurface gas-pressure failure criterion, so that fragmentation is emergent rather than prescribed. In the primary case (q=1~AU, σt=100~Pa) splitting begins at the 3~AU starting distance, once a sub-millimeter lag deposit partially confines the warming CO front; 63 binary splittings follow, with a self-limited plateau at 53 bodies before perihelion and the 64-body tracking cap reached near perihelion. Sublimation is energy-limited: total mass loss is 1.3\%, volatile depletions are at most a few per cent, and most of the mass survives as a fragment swarm; the mass budget closes to machine precision. Across the grid, mass loss (0.8--1.7\%) depends weakly on q and σt but strongly on composition, falling to 0.1\% for depleted, 67P-like ices. Yet every case, including the depleted class, disaggregates, whereas Jupiter-family comets of similar composition survive repeated perihelia, so the sealing prescription over-fragments. We regard the composition ranking, the insensitivity to σt, percent-level mass loss, and an onset beyond 3~AU as robust, and defer absolute survival predictions to calibration against well-observed comets. Mantle insulation suppresses outbound activity, producing an inbound--outbound asymmetry.
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BibTeX
@misc{karamiqucham2026fragmentation,
title = {{Fragmentation Dynamics of Pristine Interstellar Comets: An Exploratory Multi-Physics Simulation Study}},
author = {Behrooz Karamiqucham},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.20773},
eprint = {2609.20773},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.20773},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Fragmentation Dynamics of Pristine Interstellar Comets: An Exploratory Multi-Physics Simulation Study
AU - Behrooz Karamiqucham
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2609.20773
UR - https://arxiv.org/abs/2609.20773
AB - We present an exploratory numerical model for the thermal evolution and fragmentation of pristine interstellar comets on a first passage through the inner Solar System, applied over a grid of perihelion distances (q=0.25--$1.5$~AU) and tensile strengths (σ_t=50--$500$~Pa). A single nucleus (M_0=2×10^12~kg, R_0≈1.06~km, dust/ice =1, ices 35\% CO, 30\% CO_2, 15\% CH_4, 20\% H_2O) follows a hyperbolic trajectory from an initially 30~K state, with heat conduction, energy-balanced multi-species sublimation, dust lifting and lag-mantle growth, and a subsurface gas-pressure failure criterion, so that fragmentation is emergent rather than prescribed. In the primary case (q=1~AU, σ_t=100~Pa) splitting begins at the 3~AU starting distance, once a sub-millimeter lag deposit partially confines the warming CO front; 63 binary splittings follow, with a self-limited plateau at 53 bodies before perihelion and the 64-body tracking cap reached near perihelion. Sublimation is energy-limited: total mass loss is 1.3\%, volatile depletions are at most a few per cent, and most of the mass survives as a fragment swarm; the mass budget closes to machine precision. Across the grid, mass loss (0.8--1.7\%) depends weakly on q and σ_t but strongly on composition, falling to 0.1\% for depleted, 67P-like ices. Yet every case, including the depleted class, disaggregates, whereas Jupiter-family comets of similar composition survive repeated perihelia, so the sealing prescription over-fragments. We regard the composition ranking, the insensitivity to σ_t, percent-level mass loss, and an onset beyond 3~AU as robust, and defer absolute survival predictions to calibration against well-observed comets. Mantle insulation suppresses outbound activity, producing an inbound--outbound asymmetry.
ER -