CANFind: solar system object detection in the NOAO Source Catalog

Solar system objects (SSOs) reveal insight into the evolution of planetary systems, and are discernable from distant stars and galaxies by their high proper motion. Bright, nearby objects that could potentially impact Earth are most easily detected; on the other hand the dim asteroids, comets, and minor planets of the outer solar system are harder to see and less often discovered. With 34 billion measurements of 2.9 billion unique objects, the first data release of the NOAO Source Catalog (NSC, Nidever et al. 2018) contains observations of many SSOs across the solar system. Measurements from 255,000 exposures cover approximately ¾ of the sky and reach an average depth of ~23 mag. I present the results of CANFind (a Computationally Automated NSC tracklet Finder), a new algorithm developed for SSO detection run on the contents of NSC DR1. By applying a clustering algorithm to the NSC data followed by a validation process, measurements are identified by CANFind as belonging to either moving objects (asteroids, comets, minor planets) or “stationary” objects (stars, galaxies) based on their spatial distribution with 96% efficiency for proper motions below 200 arcsec/hr. Detections of moving objects are clustered together to form linear “tracklets”, each containing 3+ detections per object. CANFind identified over 500,000 tracklets in NSC DR1 over an area of sky covering ~27,000 square degrees, mainly within 30 degrees of the ecliptic and in the southern celestial hemisphere. Proper motions are consistent largely with Main Belt Asteroids and, to a lesser extent, with other groups and families including Jupiter Trojans, Hilda asteroids, and Trans-Neptunian Objects. Apparent magnitudes range from 10-25 mag across u, g, r, i, z, Y, and VR bands. Particularly for the 170,000 tracklets detected within 5 degrees of the ecliptic, the data show a bimodality of tracklet color between primarily carbonaceous (blue) and siliceous (red) groups. Orbits will be fit to tracklets and the resulting SSO candidates will be studied for size distribution, color, and orbital parameters.