two exiled stars are leaving our galaxy forever
They are surely travelling fast!
These have recently been discussed here.
Does a hypervelocity star leave a fiery trail, like a comet's dust tail?
There is no reason for a star of any velocity to "leave a fiery tail".
A comet's tail is produced by the radiation pressure (dust tail) and solar wind/magnetic field (ion tail) coming from the Sun.
If a star is moving close by another very powerful O/B star then the radiation pressure and possible stellar wind emanating from that could act of the former's corona and produce some sort of tail, however ithe passing star is more likely to produce a shadow in the O/B stellar wind nebula, similar to the Cone nebula.
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