On the night of august 8th, 2019 i was out about 11 p.M. when i looked up to watch an airliner flying overhead at a fairly low altitude, assuming it was on approach to land at the boise airport. i t was a clear night, and stars were also visible as i first saw the airliner close to overhead but to my south. it was nothing out of the ordinary as i've seen many airliners fly over in my life but then i noticed one of the bright stars which at the time i guessed was jupiter as it was a bright star and i was looking to the south but as i watched the plane going over i noticed the one i assumed was jupiter was traveling alongside the jet. as that is nowhere near normal i watched the object which was to the south of the jet that was traveling east and trailing slightly behind it. i could only maintain sight for about 15 seconds before both the jet and the object went behind a treeline.