I performed follow-up measurements of this object while it was still on the PCCP webpage. Stacking of 12 unfiltered exposures, 120 seconds each, obtained remotely on 2019, May 06.4 from H06 (iTelescope network) through a 0.25-m f/3.4 reflector + CCD, shows that this object is a comet with a diffuse coma about 10 arcsec in diameter.
M.P.E.C. 2019-J122, assigns the following preliminary orbital elements to comet C/2019 J1: T 2019 Apr. 8.80; e= 0.97; Peri. = 167.59; q = 2.48; Incl.= 24.54
by Ernesto Guido