Space Weathering Within C-Complex Main Belt Asteroid Families

The Sloan Digital Sky Survey (SDSS) Moving Object Catalog is a valuable dataset that contains photometric observations of over 100,000 unique known moving objects. Previous studies have used the SDSS Moving Object Catalog photometry to investigate the distribution of taxonomic types across the Main Belt (Carvano et al. 2010, DeMeo & Carry 2013), the colors of the Main Belt families (Parker et al. 2008), and space weathering trends both between families (Nesvorny et al. 2005) and within certain families (Thomas et al. 2012). All of these works have demonstrated that the SDSS photometry can be reliably used to distinguish between taxonomic classes and determine spectral slopes. The ability of this dataset to determine spectral slopes for large numbers of objects is particularly important to the study of spectral trends associated with space weathering.

Using data from the SDSS Moving Object Catalog, we study color as a function of size for C-complex families in the Main Belt to improve our understanding of space weathering of carbonaceous materials. We find two distinct spectral slope trends: Hygiea-type and Themis-type. The Hygiea-type families exhibit a reduction in spectral slope with increasing object size until a minimum slope value is reached and the trend reverses with increasing slope with increasing object size. The Themis family shows an increase in spectral slope with increasing object size until a maximum slope is reached and the trend plateaus or has a potential decrease in spectral slope for the largest objects. The Themis family is the only family studied to not show the Hygiea-type slope trend. The processes responsible for these distinct changes in spectral slope affect several different taxonomic classes within the C-complex and appear to act quickly to alter the spectral slopes of the family members.