I checked the Iridium satellite tables and also the other major bright orbiting bodies, and nothing matches. It looks like a meteor trail, but was captured over three 15 second exposures, in a fairly polar orbit ( NNE to SSW ). Even if it only just caught the back end of the first exposure, and start of the third, it was still over 15 seconds duration, and so unlikely to be a meteor. There's no sign of any faint trail leading into or away from the object, making a satellite less likely, and I can't find it listed in any prediction tables. So it could be a military satellite that's not listed, slowly rotating and catching the Sun, but otherwise invisible - hence no trail in or out of the bright streak. - 22-10-17