Big-Box Solar System Science with Serendipitous ATLAS Photometry

Since 2017 the Hawaii-based ATLAS near-Earth asteroid (NEA) detection system (Tonry et al. 2018) has monitored the entire dark sky from the north celestial pole to declination -50 every two nights to a dark-time sensitivity of V=19.7. In 2022, two additional ATLAS telescopes were installed in the southern hemisphere, allowing the system to monitor the entire dark sky from north to south celestial poles nearly every night. The uniform ATLAS all-sky survey has serendipitously detected over 500,000 different solar system objects, of which there are 150,000 asteroids and 179 comets with over 250 ATLAS observations spanning a wide range of observing geometry. The multi-band high-quality ATLAS photometry and accurate observation timing allow for shape modeling via folded lightcurves and subsequent taxomonic discrimination for a great number of these asteroids. All ATLAS calibrated exposures are maintained on disk, enabling on-demand forced photometry or stacking of historical observations to search for signatures of cometary or disruption activity. We present the initial release of the ATLAS solar system photometry catalog: a collection of serendipitous observations of solar system objects from ATLAS NEA survey operations, positionally matched to ephemerides, and measured against the ATLAS Refcat (Tonry et al. 2018) photometric reference standard.