Resurfacing asteroids from YORP spin-up and failure

•Using Sloan Digital Sky Survey colors, we show an orbitally independent decrease in gri-slope for decreasing size of S and Q-type asteroids.•We accurately match the decreasing gri-slopes with decreasing size with a YORP spin-up and failure, and space weathering model.•For YORP spin-up and failure to be the primary resurfacing mechanism for small asteroids, the e-folding space weathering timescale must be between 19 and 80 Myr in the inner main belt.•Using this e-folding timescale, we estimate the space weathering timescale to weather a Q-type into an S-type to be approximately 8–35 Myr in the inner main belt or 2–7 Myr at the orbit of Earth. The spectral properties of S and Q-type asteroids can change over time due to interaction with the solar wind and micrometeorite impacts in a process known as ‘space weathering.’ Space weathering raises the spectral slope and decreases the 1 µm absorption band depth in the spectra of S and Q-type asteroids. Over time, Q-type asteroids, which have very similar spectra to ordinary chondrite meteorites, will change into S-type asteroids. Because there are a significant number of Q-type asteroids, there must be some process which is resurfacing S-type asteroids into Q-types. In this study, we use asteroid data from the Sloan Digital Sky Survey to show a trend between the slope through the g′, r′, and i′ filters, called the gri-slope, and size that holds for all populations of S and Q-type asteroids in the inner solar system, regardless of orbit. We model the evolution of a suite of asteroids in a Monte Carlo YORP rotational evolution and space weathering model. We show that spin-up and failure from YORP is one of the key resurfacing mechanisms that creates the observed weathering trends with size. By varying the non-dimensional YORP coefficient and running time of the present model over the range 475–1425 Myr, we find a range of values for the space weathering timescale, τSW ≈ 19–80 Myr at 2.2 AU. We also estimate the time to weather a newly resurfaced Q-type asteroid into an S-complex asteroid at 1 AU, τQ → S(1AU) ≈ 2–7 Myr.