# Evidence against non-gravitational acceleration of 1I/2017 U1 `Oumuamua

## TL;DR

This paper critically examines the claim of non-gravitational acceleration in 'Oumuamua's orbit, questioning the evidence for comet-like outgassing as its cause and highlighting inconsistencies in the data analysis.

## Contribution

It provides a critical analysis challenging the interpretation of non-gravitational acceleration in 'Oumuamua, suggesting alternative explanations and scrutinizing the data fitting process.

## Key findings

- Questionable gas to dust ratio implications
- Doubts about the orbital fit improvements
- Skepticism towards non-gravitational acceleration evidence

## Abstract

Micheli, et al. (2018) reported that a seven-parameter fit to the orbit of 1I/2017 U1 `Oumuamua indicated a non-gravitational acceleration in the anti-Solar direction, and attributed it to recoil from comet-like outgassing. The implied gas to dust ratio is at least 100 times greater than that of known Solar System comets. The reported collapse of the scatter of nearly contemporaneous coordinate residuals upon inclusion of the non-gravitational term in the orbital fits is difficult to understand. There are grounds for skepticism.