This will be the last light curve of the week for 2021, and we will stick with targets from Orion, as it is nicely visible at the moment. This week’s object is from the L1641N cluster, just South of the main M42 Orion Nebula.

The object we look at is the know variable star PR Ori. This is a bright-ish star near the centre of the field and characterised as an Orion type variable. Our light curve shown above in the V, R and I filters shows some general longer term variability with an amplitude of about half a magnitude. This, looks periodic with  period of about five years, but we need a few more years of data to verify this.

Additionally there is short term scatter with roughly the same amplitude. This occurs more or less randomly, hence the above mentioned classification. There are a few occasions where the star dips in all filters, indicating small dense structures in the inner disk.