Hello,

Timeseries observations of ASASSN-24hd through a V filter were done on 24 and 25 Dec 2024 at CBA KKO. They covered the epochs JD 2460669.35-2460669.48 and JD 2460670.34-2460670.51 respectively.

The LCs on both nights showed a clear periodic modulation (superhumps) in the shape of a saw tooth, a pattern that seems to occur with many outbursting ugwz stars seen over the years.

The amplitude of the cyclic modulation during those nights were about .25V and .20V resp. and the mean brightness's were 12.79V and 12.92V. A period analysis using the PDM and GLS methods with Peranso 3.0 yielded a period of 0.583d +/- 0.003d on both nights, and considering the total observing baseline over the two nights a mean period of 0.580d +/- .0015d was derived.

Earlier observations done on 19 Dec (mid-time JD 2460664.38) showed the object at a brightness of 12.06V but without any clear modulation.

From the discovery data it can be concluded that the superhumps started between 8 and 12 days into the outburst. The large amplitude outburst, the considerable delay in the formation of superhumps, the LC pattern of the superhumps and the relative short periodicity of them ought to direct towards the ugwz status of ASASSN-24hd.

Further observations are planned, weather allowing

Berto Monard / CBA KKO

Calitzdorp / South Africa