Hi folks, totally new here so here goes. I've done a fair bit of background reading on variable stars and photometry but have never really given it a go til now. A few nights ago I was collecting a series of images of Pluto for an animation and while watching the images come in I noticed a faint star next to Pluto gradually brighten. I took the images and ran them through MaximDL photometry function and AIP4WIN as well and came out with the same thing. A light curve that brightens by around 2 magnitudes in an hour before slowly tappering off. I've caught this same pattern on two nights now when I have had around 9 hours of data for each night. The star is initially much fainter than Pluto and then brightens to around the same.
I've looked for an identification for the star but I haven't been able to find it in the databases here or elsewhere.