Last week we looked at the star LkHa271. So lets look this week at the object which is the entry before this in the catalogue of emission line stars: LkHa270. Naturally it is also in the NGC1333 star forming region. However there is so far no reliable parallax from Gaia. This is probably caused either by the object being a binary or the small reflection nebula the source is placed in.

We show the V, R, and I-band light curve of the source. It resembles what one could call the quintessential young star behaviour. It varies on short timescale by about half a magnitude with some lower amplitude long term trends. There are some clear outliers in the photometry. These are almost all exclusively errors in the photometry caused by the presence of the small reflection nebula that surrounds the source. The nebula is present in all wavelength and depending on the resolution and limiting magnitude can cause problems for the correct measurements of the brightness, as it makes it hard for the automatic software to determine the background sky level.

This is a good example that for detailed analysis of large numbers of light curves it is very important have good systems to identify potential problems with the photometry. Such objects then need to be treated with care or removed from the analysis in order to avoid contamination.