[Paper Review] Spatial separation effect of asteroids with different albedos

A. M. Kazantsev|ArXiv.org|Jun 17, 2008

Astro and Planetary Science3 citations

TL;DR

This study investigates the spatial separation of asteroids based on albedo differences using numerical orbit integration of 1,694 IRAS-listed asteroids from 1996 to 2006. It finds that low-albedo asteroids experience a greater increase in semimajor axis over time compared to high-albedo ones, suggesting a non-gravitational effect driving a separation rate of ~1 AU per 100 My, supported by family distribution analyses like Flora.

ABSTRACT

Numerical calculations of orbit evolutions of 1694 numbered asteroids included in the IRAS catalogue, from 13.11.1996 to 06.03.2006 were carried out. The values da - differences between the catalogue semimajor axes at 06.03.2006 and the calculated ones were computed. The average dependence da on albido p shows decrease of da at increase of p, and it is significant. In other words, semimajor axes of low-albedo asteroids are, on average, increasing as compared with high-albedo ones. Speed of such possible spatial separation for very dim and very bright asteroids of from 10 to 50km in order of magnitude is about 1 AU per 100 My. To explain this fact it may suppose an existence possibility of a non-gravitational effect. Such supposition is confirmed by distributions p(a) for asteroid families, above all, Flora family. An analysis of errors and residuals in the used asteroid catalogues is evidence of such supposition.

Motivation & Objective

• To investigate long-term orbital evolution differences between asteroids of varying albedos.
• To determine whether observed discrepancies in semimajor axes correlate with albedo, suggesting non-gravitational forces.
• To assess the reliability of asteroid catalogues by analyzing residuals and errors in orbital data.
• To evaluate the role of thermal forces (non-gravitational effects) in shaping asteroid orbital distribution.
• To examine the p(a) distribution in asteroid families, particularly Flora, to support the existence of such effects.

Proposed method

• Numerical integration of orbital elements for 1,694 numbered asteroids from November 13, 1996, to March 6, 2006.
• Computation of the difference (da) between cataloged and calculated semimajor axes at the final epoch to detect drift.
• Analysis of the dependence of da on albedo (p), revealing a systematic trend with increasing p.
• Comparison of observed da trends with expected gravitational dynamics to isolate non-gravitational contributions.
• Examination of albedo distribution (p(a)) in asteroid families, especially Flora, to validate the presence of non-gravitational effects.
• Statistical evaluation of errors and residuals in IRAS and other asteroid catalogues to assess data reliability.

Experimental results

Research questions

• RQ1 Does the semimajor axis of asteroids systematically increase with decreasing albedo over time?
• RQ2 To what extent do discrepancies in cataloged versus calculated semimajor axes correlate with albedo?
• RQ3 Could non-gravitational forces explain the observed orbital drift between low- and high-albedo asteroids?
• RQ4 How do the p(a) distributions in asteroid families like Flora support or contradict the existence of such effects?
• RQ5 Are the observed residuals and errors in asteroid catalogues consistent with the presence of non-gravitational perturbations?

Key findings

• Low-albedo asteroids exhibit a greater increase in semimajor axis compared to high-albedo ones, with da decreasing as albedo increases.
• The spatial separation rate between very dim and very bright asteroids of 10–50 km size is approximately 1 AU per 100 million years.
• The observed trend in da vs. albedo is statistically significant and inconsistent with pure gravitational dynamics.
• Analysis of the Flora asteroid family shows a p(a) distribution that supports the existence of a non-gravitational effect.
• Residuals and errors in asteroid catalogues are consistent with the presence of a non-gravitational force acting on asteroids.
• The results suggest that thermal forces (Yarkovsky effect) may be responsible for the observed orbital drift, though not explicitly modeled in this work.