On 27 June 2018, astronomers reported a non-gravitational acceleration to ʻOumuamua's trajectory, potentially consistent with a push from solar radiation pressure.
[19][20][52] Initial speculation as to the cause of this acceleration pointed to comet off-gassing,
[53] whereby portions of the object are ejected as the sun heats the surface. However, multiple objections have been raised to this possibility. Researchers point out that no such tail of gasses was ever observed following the object. Additionally, the anomalous acceleration was not observed when ʻOumuamua was passing at its closest to the sun as would be expected. A follow up analysis of these claims identifies that, were ʻOumuamua a comet, the off-gassing should have caused such an increase in rotational torque as to tear the object apart.