This week we have a look at the HOYS data for the star RW Ori. It is in the well observed Sigma Ori target region of the project. towards the end of 2023 we had a look at this object during weeks 254 and 255. We found that the star had several variability ‘modes’. It seemed to vary with a period of about a week and small amplitudes. This is most likely the rotation period. Additionally there are semi regular variations of the order of a month or two which vary in period and amplitude. In some cases they obscure the short period variations completely. These are most likely caused by material in the inner disk, obscuring the star at times.
In the above plot we show the data for the last observing season. We can see that there have three of these longer term features, but for most of the time the source was quite ‘calm’. If one zooms into these parts of the light curve, the roughly one week period becomes again very prominent. It will be interesting to see if there are any long term trends in the occurrence of the large time scale variations … student project 🙂