This week we look look at the HOYS light curve of the T-Tauri star V608Mon. It is situated just North of the Cone Nebula, in the young cluster NGC2264. Based on its distance and proper motion, it is a bona fide member of the cluster. In images taken at optical wavelengths, the star is surrounded by a reflection nebulosity. In particular there is an outflow or wind driven cavity visible pointing South-West from the source that extends about half an arc-minute. Thus, photometry of the star is slightly hampered as it ‘sits’ right in the extended emission.

Nevertheless, we have a nicely sampled light curve as shown (V, R, and I) in the above image. In total we have now data from nine observing seasons – though year one (2015/16) has only two data points. The object shows some longer term general variations of just under one magnitude. In the last three years the short term variability has apparently increased to almost the same level. Some of this might be a bias, as in the earlier years the data are much more sparse and thus we might have missed some of the short term changes.

The variations in colour show a large-ish scatter, which in part might be due to the photometry issues. However, generally the variability in brightness does not seem to change the colour of the star. This could hint, together with the appearance in the images, that the light might be dominated by scattered light, which has passed through a thick layer of large grain dust particles. This is one of the objects where changes in brightness of the central star should propagate outwards along the cavity walls and one might be able to observe changes in brightness of this over time moving outwards due to the light travel time.