This week we look at the light curve of the young star AH Ori, which is situated just north of the Orion Nebula, M42. The object is classified as an ‘Orion Variable’. Note that this does not mean it is named like it because it is in Orion. Rather this classification indicates that it’s brightness fluctuates stochastically. In essence if a variable young star cannot be categorised otherwise (e.g. as an eclipsing binary, dipper or burster), you put it into this category 🙂 .
The data shown are the R, V, and B-band points we have for the last 4 observing seasons. One can see clearly that the star does what it is supposed to according to its classification. From time to time it also changes its behaviour. For example, if one zooms into the 1st of the shown seasons. it originally has a smooth light curve. The day to day variations are very small (a few percent). This is only interspersed with two phases of slightly deeper dimmer events (0.3mag) lasting between a week or two. However, at some point (after JD=2460020) the object ‘goes crazy’. The day to day variations reach up to half a magnitude, and the object is generally fainter. This is most likely caused by small scale structures in the inner disk entering the direct line of sight to the star. At other times the object brightens further, maybe due to accretion rate changes.