Comet C/2013 A1 Siding Spring. How treatment of data and NG effects can change our predictions about close encounters with Mars ?

TL;DR

This study demonstrates that data treatment methods significantly influence predictions of comet C/2013 A1 Siding Spring's close approach to Mars, with gravitational models providing more consistent estimates than non-gravitational models.

Contribution

It highlights the impact of data processing choices on orbital predictions and compares gravitational and non-gravitational models for comet trajectory estimation.

Findings

Predicted closest approach distance varies with data treatment.

Gravitational models yield more consistent close encounter estimates.

Non-gravitational models remain highly uncertain, affecting prediction reliability.

Abstract

We show that the estimates of close encounter of this comet with Mars depend on data treatment. Using the data taken in the two-year period, we derived that the comet will miss Mars on 2014 October 19 at the distance of about $140\,150\pm 55$ km or $140\,300\pm 45$ km from its center, depending on the method of data processing in the purely gravitational model of motion (based on non-weighted data or weighted data, respectively). Unfortunately, the non-gravitational model of motion is still very uncertain, thus we can only speculate about estimates of expected distances for non-gravitational orbital solutions. However, we did not obtain a significant differences in close encounter prediction between the non-gravitational solutions and the gravitational ones.