With the database back, we can have a renewed look at interesting objects in our database. One of the first stars we investigated in detail, was the young variable V1490Cyg, in the Pelican Nebula field. We found semi-periodic dimming events with a period of about 31.5 days. Our conclusion was that these are caused by a warp in the inner disk, which most likely is created by a protoplanet in the system’s disk. This was published in our paper “A survey for variable young stars with small telescopes: II – mapping a protoplanetary disc with stable structures at 0.15 au” in MNRAS, and was based on data up to 2019.

One of the interesting features of the object was that each dimming event looked slightly different. This means, that the material in the part of the disk that creates the occultations changes on timescales much shorter than one orbit. In other words, we are observing the mass transport/flow through the inner part of the disk. It is hence worth looking how stable this system is. In the light curve above, we show the I-band and V-band data of the source in HOYS from 2021. Indeed, the object is still behaving in the same way.

We can clearly see semi-periodic dimming events with the same period. Some are almost two magnitudes deep, while others can barely be identified. There are dips with a more detailed structure, and others with a simple smooth decrease and increase. It is worth noting that the amount of material needed in the disk warp to cause one of the deeper dips in the light curve, only amounts to 0.02 percent of the mass of the Moon. So not a lot of material.