This week e look at the HOYS target region called L1641N and the young star called Parenago 2542. This field is situated about one degree South of the Orion nebula and contains a number of very young objects, nebulosities and jets and outflows.

The light curve looks as if there was just some long term trend with a minimum in brightness, after which the object starts to recover. This long term dip is indeed evident and the drop in brightness of roughly 0.2mag, i.e. 20% of the flux, can clearly be seen. The remaining scatter looks like measurement noise in the data,

However, when one zooms in, one finds that most of these variations seem to be caused by a periodic signal with an period of about six days. Thus, this known young stellar object seems to have spots on the surface and we can thus determine its rotation period. The long term trend is most likely caused by a larger structure in the outer accretion disk which changes the amount of light we see on a longer time scale.