1894-2020 opt-to-NIR photometry of HO Puppis

Using distance measured from Gaia Data Release 2 and the spectral-energy-distribution fit on broadband photometry, the Be-star nature of HO Pup is ruled out. Furthermore, based on the 28700 photometric data points collected from various time-domain surveys and dedicated intensive-monitoring observations, the light curves of HO Pup closely resemble those of IW And-type stars (as pointed out by Kimura+ 2020PASJ...72...22K), exhibiting characteristics such as a quasi-standstill phase, brightening, and dips.

The light curve of HO Pup displays various variability timescales, including brightening cycles ranging from 23 to 61days, variations with periods between 3.9d and 50min during the quasi-standstill phase, and a semiregular ~14d period for the dip events. We have also collected time-series spectra (with various spectral resolutions), in which Balmer emission lines and other spectral lines expected for an IW And-type star were detected (even though some of these lines were also expected to be present for Be stars).