Astronomy8 papers
Binary asteroids
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Ivana Milić Žitnik
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Astrometric detection of binary asteroids
Noam Segev et al. (2022)
- Published
- Nov 21, 2022
- Journal
- Monthly Notices of the Royal Astronomical Society · Vol. 518 · No. 3
- DOI
- 10.1093/mnras/stac3365
At a Glance
Models Gaia astrometric center-of-light wobble to search for unresolved binary asteroids and quantifies why DR2 yields few detections.
Summary
This paper develops and tests an astrometric approach to find unresolved binary asteroids by modeling how a system’s center of light wobbles around its center of mass. The key novelty is a forward model plus an inversion/search pipeline (with bootstrap-based false-positive estimation) tailored to Gaia’s along-scan astrometry and irregular sampling, aiming to probe binary parameter space that imaging, lightcurves, and radar miss. Using Gaia DR2 Solar System residuals, the authors find no strong new detections and argue this is largely because DR2’s processing clipped “outlier” transits that may contain genuine astrophysical wobble signals; nonetheless, known binaries show a small excess in astrometric scatter compared to the overall asteroid population. A case study of (4337) Arecibo yields only a marginal (∼2.2σ) period near half the DR3-reported value, underscoring both the promise and the current catalog limitations for astrometric binary discovery.
Method Snapshot
Construct a center-of-light astrometric forward model for binary orbits, then grid-search periods and fit remaining parameters to Gaia along-scan residuals with bootstrap significance tests.
Background
Familiarity with basic orbital mechanics, astrometric measurements (especially Gaia along-scan geometry), and statistical model fitting/hypothesis testing.