For a fixed transit shape, the HD 172555 dip changes more with the pulsation model than with the tested CHEOPS pipeline update

We test the reported HD 172555 dip in public CHEOPS observation 1514950. We compare DRP 13.1.0 and 14.1.2 on the same 2150 unflagged samples. We hold the transit shape fixed and fit its depth, a quadratic baseline, and periodic signals together. Eleven frequency sets, with and without instrument terms, give 44 fits. Depths range from 134.6 to 578.8 ppm. Each paired pipeline change is less than 7.9 ppm; the median absolute change is 0.87 ppm. The main 38-frequency fit gives 163.2 and 162.8 ppm. Fits with 60 or 80 TESS frequencies are poorly resolved and serve as stress tests. The depth range is unchanged when they are excluded. A signed scan finds a brightening with a local score as large as that of the candidate dip. Thus the tested pipeline update has a small effect on the fixed-shape depth, but the pulsation basis has a large effect. The local score does not establish a global detection significance or an exocomet. We preserve original FITS files, source hashes, all fits, figures, code, and offline reproduction instructions.

HD 172555 · CHEOPS · exocomets · stellar pulsations · photometry · model sensitivity · reproducible research