Could Solar Radiation Pressure Explain 'Oumuamua's Peculiar Acceleration?

TL;DR

This paper investigates whether solar radiation pressure could explain 'Oumuamua's unexpected acceleration, proposing a thin, light object as a plausible explanation and discussing its potential origins and implications for interstellar probes.

Contribution

It introduces the hypothesis that solar radiation pressure on a thin, lightweight object explains 'Oumuamua's acceleration, providing a physical model and survival analysis.

Findings

A thin sheet with a mass-to-area ratio of 0.1 g/cm² can account for the acceleration.

Such an object could survive interstellar travel over 5 kpc distances.

The model applies to light interstellar probes and their potential origins.

Abstract

`Oumuamua (1I/2017 U1) is the first object of interstellar origin observed in the Solar System. Recently, \citet{Micheli2018} reported that `Oumuamua showed deviations from a Keplerian orbit at a high statistical significance. The observed trajectory is best explained by an excess radial acceleration $\Delta a \propto r^{-2}$, where $r$ is the distance of `Oumuamua from the Sun. Such an acceleration is naturally expected for comets, driven by the evaporating material. However, recent observational and theoretical studies imply that `Oumuamua is not an active comet. We explore the possibility that the excess acceleration results from Solar radiation pressure. The required mass-to-area ratio is $(m/A)\approx 0.1$ g cm$^{-2}$. For a thin sheet this requires a thickness of $\approx 0.3-0.9$ mm. We find that although extremely thin, such an object would survive an interstellar travel over Galactic distances of $\sim 5$ kpc, withstanding collisions with gas and dust-grains as well as stresses from rotation and tidal forces. We discuss the possible origins of such an object. Our general results apply to any light probes designed for interstellar travel.