Single-Apparition Phase Curves from ATLAS survey: Photometric Parameter Determination

Abstract

Phase curves, the variations of minor planet brightness with solar phase angle, are fundamental tools for determining physical parameters such as absolute magnitude (H) and slope parameters (G1, G2) that constrain surface properties. While targeted observing campaigns provide high-precision phase curves for individual objects, survey data offer the potential to characterize vastly larger samples. However, phase curves from survey data traditionally suffer from systematic effects due to combining observations across multiple apparitions and uncontrolled rotational sampling. We investigate whether single apparition survey data, with appropriate statistical treatment of rotational variations, can achieve characterization level comparable to targeted observations. Using ATLAS survey photometry for 131 taxonomically classified asteroids, we restrict our analysis to single apparitions and validate rotational phase uniformity. Our derived photometric parameters reproduce established correlations from both targeted studies and surveys using sparse data: strong G1 − G2 anti-correlation, albedo dependencies, and clear taxonomic separation in the G1, G2 parameter space. Multi-apparition analysis for nine objects reveals that absolute magnitude H varies with viewing geometry, demonstrating that H is dependent on geometry for irregularly shaped objects rather than an intrinsic value. Slope parameter across several apparitions provides constraints on surface photometric homogeneity. Our methodology enables individual characterization directly from survey data, complementing the high-precision characterization traditionally obtained through targeted observation campaigns.