Physical modelling of near-Earth asteroid (23187) 2000 PN9 with ground-based optical and radar observations

TL;DR

This study combines optical and radar observations to model the shape and spin state of asteroid 2000 PN9, investigating YORP effect influences and suggesting possible YORP equilibrium.

Contribution

It provides a detailed physical and spin model of asteroid 2000 PN9 using combined optical and radar data, exploring YORP effect implications.

Findings

Asteroid 2000 PN9 is a large top-shaped body with a 2.53216-hour rotation period.

No evidence of YORP acceleration was detected within the sensitivity limits.

The asteroid may be in YORP equilibrium or self-limited state.

Abstract

We present a physical model and spin-state analysis of the potentially hazardous asteroid (23187) 2000 PN9. As part of a long-term campaign to make direct detections of the YORP effect, we collected optical lightcurves of the asteroid between 2006 and 2020. These observations were combined with planetary radar data to develop a detailed shape model which was used to search for YORP acceleration. We report that 2000 PN9 is a relatively large top-shaped body with a sidereal rotation period of 2.53216$\pm$0.00015 h. Although we find no evidence for rotational acceleration, YORP torques smaller than $\sim$10$^{-8}$$\,\rm rad/day^{2}$ cannot be ruled out. It is likely that 2000 PN9 is a YORP-evolved object, and may be an example of YORP equilibrium or self limitation.