Capillary Action in a Crack on the Surface of Asteroids with an Application to 433 Eros

TL;DR

This paper models capillary action in surface cracks of irregular asteroids, considering gravitational effects, and applies the findings to asteroid 433 Eros to understand liquid distribution.

Contribution

It introduces a model for capillary height influenced by asteroid gravity and applies it specifically to asteroid 433 Eros, considering different capillary orientations.

Findings

Capillary height depends on gravitational irregularities.

Liquid distribution on asteroid surfaces is inhomogeneous.

Orientation of the crack affects liquid height calculations.

Abstract

Some asteroids contain water ice, and a space mission landing on an asteroid may take liquid to the surface of the asteroid. Gas pressure is very weak on the surface of asteroids. Here we consider the capillary action in a crack on the surface of irregular asteroids. The crack is modelled as a capillary which has a fixed radius. An asteroid s irregular gravitational potential influences the height of the liquid in the capillary. The height of the liquid in the capillary on the surface of such asteroids is derived from the asteroid s irregular gravitational potential. Capillary mechanisms are expected to produce an inhomogeneaous distribution of emergent liquid on the surface. This result is applied to asteroid 433 Eros, which has an irregular, elongated, and concave shape. Two cases are considered 1) we calculate the height of the liquid in the capillary when the direction of the capillary is perpendicular to the local surface of the asteroid; 2) we calculate the height of the liquid in the capillary when the direction of the capillary is parallel to the vector from the center of mass to the surface position. The projected height in the capillary on the local surface of the asteroid seems to depend on the assumed direction of the capillary.