This week marks the 6th anniversary of our light curve of the week feature!
To ‘celebrate’ we show one of the less remarkable light curves, that do not get much attention usually. In the above plot we show the B, V, R, and I-band data for HD294274, which is located in the sigma-Ori cluster field. We display the data from two observing seasons ago, and include the error bars of the photometry.
As we can see, with the exceptions of a few outliers, the star does not vary within the photometric uncertainties, which are only of the order of a few percent. The star is a known YSO, but it is not a sigma-Ori member. It is 100pc closer and has a very different proper motion than the cluster members. Thus, it might be a miss-classification, or it is a member of a younger foreground population.
Whatever the nature of the star, we use objects like this to calibrate our photometry against. Because they do not change, we know their brightness and colour. Thus, for each image we know how bright it (and other similar stars) should be, which allows us to accurately calibrate our data. Boring is good in this case 🙂