What is it about?
We explain that cohesive forces, similar to those present in powders such as flour or dust on Earth, influence the mechanical strength of small asteroids. On Earth, the influence of these forces is only detectable for dust particles as, due to their small size, their weight is comparable to cohesion. However, in an asteroid where gravity is about a million times smaller than on Earth, the effects of cohesion should be observed for much larger grains, up to cm in size. This, along gravitational attraction, allows small asteroid to rotate beyond the gravitational limit.
Featured Image
Why is it important?
It has been observed that asteroid with sizes above ~100m have a spin limit. This is, they cannot rotate with spin periods below ~2.3h. However, this is not true for smaller asteroids. For some time it has been known that these asteroids had to be cohesive, but the source of the cohesive strength was elusive. In this small paper (and the subsequent longer paper) we explain how Van der Waals cohesion could be the possible source of this strength.
Perspectives
This was written almost 10 years ago and the work continued after that. Up to certain degree this paper has been confirmed by the low strength of the surface of asteroid Bennu (OSIRIS-REx mission). The surface was covered by rocks and pebbles which meant that its cohesive strength to be very small and this was exactly what was calculated.
Dr Diego P Sánchez Lana
University of Colorado Boulder
Read the Original
This page is a summary of: Granular cohesion and fast rotators in the NEA population, January 2013, American Institute of Physics,
DOI: 10.1063/1.4812091.
You can read the full text:
Contributors
The following have contributed to this page
