$V$-band photometry of asteroids from ASAS-SN: Finding asteroids with slow spin

TL;DR

This study analyzes V-band photometry from ASAS-SN for 20,000 bright asteroids, deriving spin and shape models for over 760, including 163 new solutions, revealing trends like the scarcity of slow rotators and spin orientation patterns.

Contribution

It provides the first comprehensive spin and shape models for a large asteroid sample using ASAS-SN data, significantly increasing success rates over previous surveys.

Findings

Successfully derived spin and shape models for 760 asteroids.

Identified 163 new asteroid spin solutions.

Confirmed the underrepresentation of slow rotators and anisotropic spin distributions.

Abstract

We present $V$-band photometry of the 20,000 brightest asteroids using data from the All-Sky Automated Survey for Supernovae (ASAS-SN) between 2012 and 2018. We were able to apply the convex inversion method to more than 5,000 asteroids with more than 60 good measurements in order to derive their sidereal rotation periods, spin axis orientations, and shape models. We derive unique spin state and shape solutions for 760 asteroids, including 163 new determinations. This corresponds to a success rate of about 15%, which is significantly higher than the success rate previously achieved using photometry from surveys. We derive the first sidereal rotation periods for additional 69 asteroids. We find good agreement in spin periods and pole orientations for objects with prior solutions. We obtain a statistical sample of asteroid physical properties that is sufficient for the detection of several previously known trends, such as the underrepresentation of slow rotators in current databases, and the anisotropic distribution of spin orientations driven by the nongravitational forces. We also investigate the dependence of spin orientations on the rotation period. Since 2018, ASAS-SN has been observing the sky with higher cadence and deeper limiting magnitude, which will lead to many more new solutions in just a few years.