The observing season for our Winter targets is slowly coming to an end – the Summer targets are now rising shortly after midnight. Thus, we have a look at an interesting object in the Orion Nebula field – the young star AA Ori. It is situated in the South of the nebula and know as an Orion Type variable. This usually means it varies seemingly randomly in brightness.

We have a huge amount of data for this field and the entire light curve for this object now contains more than 11400 data points over the past 7yr. Thus, we only show the B, V, and I data for the observing season 2019-2020. During that time, one can see that the star shows a dipping behaviour, i.e. decreases its brightness for 1-2weeks in a semi-regular pattern. In other observing seasons, the object has been ‘quiet’ for long periods or shows more ‘chaotic’ changes and longer term dips.

One of the projects we are pursuing is to investigate the statistics of these dipping events. Hopefully there will be a summer student project that finds a way to automatically find the dips, measure when they occur, how long and how deep they are. This can then be used to study the statistics of the material distribution in the inner disks and even find potentially periodic dipping events.