Do people see or read our light curve of the week posts, and do they have any impact? Well, let see. In February our post number 166, looked at the data of the FU-Ori variable Gaia17bpi. According to the website statistics, 20 people viewed it on the website and spend on average 3m 23s reading it. That is not one of the best viewing figures for these posts. Indeed 78 different posts have higher viewing figures (note, only the last 117 posts are on the website). A further 61 people saw it on Facebook and it got shown to 36 people on Twitter – all about average or worse.
However, in the the original post we discuss that the number of images taken for this particular HOYS target region had significantly decreased in the two years prior. We asked for the target to be observed a bit more often to ensure we do not miss any unexpected behaviour of the source, and of course keep an eye on all the other objects in the same field. The above plot shows our full R and I-band light curve of the object. There is also a large number of V-data, which is not shown for clarity.
The original post was written just after the first data point that is visible in the large group of data on the right hand side of the plot. Hence, our post had the intended effect to engage our participants in observations of this target. A big thank you to everyone who has been observing this (and all the other) fields since. Keep it up please.
We can see that the object is still roughly in it’s bright state. The intrinsic variability in the I-band seems to have increase to about 0.5mag. It looks more noisy lately, but this seems to be caused by a change in the timescale of this variability. In other words, the roughly half magnitude variations have been there before, but they occurred over longer times. This has now changed to shorter timescales. We can also see that the source underwent a general 0.5 magnitude dimming. This is is similar to the slightly deeper dimming event observed almost three years ago.
Continued observations of these rare sources are important. So far we still do not fully understand how these sources erupt in the first place. But we even less understand when and how they return to their original brightness. Are the dimming events relevant? Is the change in small amplitude variability timescale important or not?