Gravitational Capture of Large Interstellar Planetesimals by Collapsing Prestellar Cores
Abstract
We investigate the capture of free-floating planetesimals by the time-varying gravitational potential of a collapsing prestellar core. We use one-dimensional collapse models to estimate the volume of space from which planetesimals are captured. We combine this calculation with an estimate of the size distribution and velocity dispersion of the free-floating planetesimal population to determine the largest planetesimal that is typically captured, as well as the total mass of all planetesimals captured by a given protostar. We consider two cases: one in which the free-floating planetesimal population comes from the birth cluster of the star, and one in which the planetesimals are captured from the Galactic population of free-floating planetesimals. We find that the details of the collapse matter substantially, with the predicted diameter of the largest captured body from the Galactic population ranging from $2.8$ km to $6.4$ km depending on collapse model, and the largest body from our model birth cluster environment ranging from $70$ km to $1200$ km, for assumed velocity dispersions ranging from 0.7 to 8.5 km/s. The total solid mass captured by this mechanism does not exceed 0.07 Earth masses in all cases. We discuss the effect of these captured objects on the planet formation process, and argue that while the total solid mass captured is likely not significant, the largest captured bodies may grow to planet size via accretion of pebbles present in their host disks. This process may accelerate planet formation, or enable it in disks that have difficulty in forming their own planetesimals.
Related
- Capture of Interstellar Planetesimals in Protoplanetary Discs in Binary Star Systems
- Capture of interstellar planetesimals in protoplanetary discs in binary star systems
- Capture of interstellar objects during stellar encounters
- Enhancing Constraints on Ultralight Axion Dark Matter from Gravitational Capture
- Sulphur-bearing molecule survey towards prestellar and starless cores in the Perseus molecular cloud
BibTeX
@misc{anderson2026gravitational,
title = {{Gravitational Capture of Large Interstellar Planetesimals by Collapsing Prestellar Cores}},
author = {Richard Anderson and Kedron Silsbee},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.00537},
eprint = {2611.00537},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.00537},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Gravitational Capture of Large Interstellar Planetesimals by Collapsing Prestellar Cores
AU - Richard Anderson
AU - Kedron Silsbee
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.00537
UR - https://arxiv.org/abs/2611.00537
AB - We investigate the capture of free-floating planetesimals by the time-varying gravitational potential of a collapsing prestellar core. We use one-dimensional collapse models to estimate the volume of space from which planetesimals are captured. We combine this calculation with an estimate of the size distribution and velocity dispersion of the free-floating planetesimal population to determine the largest planetesimal that is typically captured, as well as the total mass of all planetesimals captured by a given protostar. We consider two cases: one in which the free-floating planetesimal population comes from the birth cluster of the star, and one in which the planetesimals are captured from the Galactic population of free-floating planetesimals. We find that the details of the collapse matter substantially, with the predicted diameter of the largest captured body from the Galactic population ranging from $2.8$ km to $6.4$ km depending on collapse model, and the largest body from our model birth cluster environment ranging from $70$ km to $1200$ km, for assumed velocity dispersions ranging from 0.7 to 8.5 km/s. The total solid mass captured by this mechanism does not exceed 0.07 Earth masses in all cases. We discuss the effect of these captured objects on the planet formation process, and argue that while the total solid mass captured is likely not significant, the largest captured bodies may grow to planet size via accretion of pebbles present in their host disks. This process may accelerate planet formation, or enable it in disks that have difficulty in forming their own planetesimals.
ER -