Searching for Binary Asteroids in Pan-STARRS1 Archival Images

TL;DR

This paper introduces two novel PSF analysis techniques to identify wide separation binary asteroids in Pan-STARRS1 archival images, aiming to expand the known population and improve understanding of binary stability.

Contribution

It develops and applies two new PSF analysis methods to detect wide binary asteroids in large survey data, enhancing detection capabilities beyond previous known binaries.

Findings

Identified new binary asteroid candidates in Pan-STARRS1 data.

Demonstrated effectiveness of PSF analysis techniques for binary detection.

Provided insights into the frequency of wide binary asteroids.

Abstract

We developed two different point spread function (PSF) analysis techniques for discovering wide separation binary asteroids in wide field surveys. We then applied these techniques to images of main belt asteroids in the 4 to 60 km size range captured by Pan-STARRS1. Johnston (2019) lists fewer than 10 known binaries in this size range with separations greater than 10% of the primary's Hill radius, so discovering more wide binary asteroids is crucial for understanding the limits of binary stability and improving our knowledge of asteroid masses. We analyzed each image by: i) comparing the major axis orientation of the asteroid's elliptical PSF to its non-sidereal rate on the sky, and ii) comparing the one-dimensional median profile created by collapsing the image along the asteroid's direction of motion to that of nearby field stars. For both methods, we flagged any results that deviated significantly from the expected measurements of single asteroids, and those targets with the most flags were identified as binary candidates for confirmation with high-acuity imaging.