We look at the light curve of the young star V397Ori today. It is situated in the outskirts of the Orion nebula (M42) and we looked at last years data in a previous post. The figure above shows the data in V, R, and I from the last observing season. Note that the magnitudes are shifted a bit to make things easier to see.

We see a lot of scatter (about 1mag) in the data, plus some obvious outliers. These are from photometric errors and we have now a selection of routines that reliably identify these points in post-processing and remove them from the light curves. We aim to describe the details in a future post. For now: ignore the obvious outlier data 🙂

There seems to be a general long term variation in the data for last winter, with an amplitude of about 0.2mag, most apparent in the V-band data. The “noise” on top of this is real variability. It is correlated in the different filters and the about 5day periodicity is still apparent. Though there are clear deviations from it. Sometimes there are one day long dimming events and even adjacent 5day cycles do not look the same. Clearly this is a very complex object and needs a detailed analysis.