We are getting closer to Christmas, hence this week’s light curve comes from a star in the Christmas Tree Cluster, which is also known as NGC2264. This is a region with a very large number of young stars and bright extended nebulosities – ideal for making pretty pictures. Especially the Cone Nebula, situated to the South of the cluster is a personal favourite.

The star we look at is called NGC2264-52, and situated in the South-West of the cluster. Like for most HOYS fields, we have now seven years of data. The star shows no long term variations, i.e. the average brightness each year is constant. However, there are clear short term variations and we have zoomed into those for a part of the light curve from last winter. A careful inspection of the image above shows that there is a periodic signal with a period of about one week. This is especially evident in the second half of the data shown.

There are one or two occasions where it seems that there are additional dips in the light curve as well. When inspecting the details of the data from the other years, it becomes evident that the periodic signal is less evident in other years. Thus, this is a candidate source where the periodic light curve is caused by spots on the stellar surface which are changing their properties over time. It will eventually be included in our general study of these sources in HOYS.