The rapidly evolving surface of asteroid 4 Vesta revealed by rayed craters and optical maturity
E.S. Costello , C.J. Tai Udovicic, L. Sun, P.G. Lucey
Icarus, available online 2 April 2026, 117075
“Highlights
- Limited lunar-like space weathering occurs on Vesta.
- Crater rays on Vesta only persist for tens of millions of years.
- Gardening processes on Vesta are much more intense than on the Moon.”
“We investigate the evolving surface of asteroid 4 Vesta using rayed craters and optical maturity parameters. Although largely unweathered, Vesta displays maturity anomalies in the form of bright and dark crater ray systems that contrast with the background regolith. We produced and utilized global maps of OMAT (Optical Maturity Parameter) and the Vesta-specific CC*-OMAT (Carbonaceous Chondrite OMAT), which quantitatively capture the effects of darkening and “bluing” due to the admixture of exogenic carbonaceous chondrite material, to catalog 207 OMAT-rayed craters. We find that rayed craters on Vesta are exceptionally ephemeral, persisting for only tens of millions of years – a lifespan of up to two orders of magnitude shorter than the roughly billion years during which rays persist on the Moon. This rapid erasure rate implies that surface processes and impact gardening on Vesta are much more intense than on the Moon. An apparent size-dependence in degradation suggests that material mixing is the dominant control on the erasure of rays, rather than an influx of carbonaceous chondrite material.”
