This week we have a look at the variable young star NZ Mon. It is situated in the south of the NGC2264 star forming region. This young cluster harbours numerous interesting young stars and is situated about 820pc away. NZ Mon’s parallax places it at the ‘near-side’ of the region, at a distance of about 760pc.

We show the I-band light curve of the object in the image above. There are now data for six observing seasons available for this region in the HOYS database. The seasonal gaps due to the objects position are also clearly visible. The star itself is classified as a T Tauri star and typically varies stochastically by about 0.1mag around a mean brightness. However, one can also see that over the last five years the star has systematically increased it’s brightness by 0.2mag – 20%.

Investigating these long term changes is one of the goals of HOYS. We will look at the changes in brightness and colour to identify potential causes for these changes. These can range from accretion rate variations, change of extinction to the star through the disk or even changes of the emission from the disk itself.