This week we look at the light curve of the namesake of one of our target fields, the young star V555Ori, which is situated about a degree North of the Orion Nebula. It was flagged up in 2017 as a variable Gaia17afn, and the Gaia light curve shows that it basically varies by up to three magnitudes all the time on all sorts of time scales.
We looked at the object in week 229, where in particular the short term variability was evident. In the above plot we show the 2023/24 R and I-Band data of the source. And again, the variations of 2-3mag are very much evident. If one zooms into the light curve at JD=2460424 one finds a one day long dimming event that is almost 2mag deep. But we can see it in all filters, so it is real and not a problem with the photometry in one of the images.
Hence, most likely there are very small scale, dense structures in the very inner disk which cause these rapid and extensive changes in brightness. Or there are ongoing continuous changes in the mass accretion rate onto the star. A detailed analysis of the colour magnitude diagram will help to decide between the options.