As evident from the weekly light curve posts, the focus of our project is on young stars and those typically vary. However, they typically vary by a small amount. This means, by up to half or maybe one magnitude, if not less. These variations are typically caused by bright or dark spots and rotational modulation, smaller changes in the mass accretion rate or line of sight extinction in the accretion disk.
Larger magnitude changes (above one magnitude) are rare, even amongst the young stars. These are usually caused by large changes in the mass accretion rate (outbursts) or much more often by the movement of large amounts of dust in the disk into the line of sight. We recently looked at one such case, the outbursting young star Gaia19fct.
This week we look at a source just 90 arcseconds south of Gaia19fct, called IRAS 07069-1026. In the light curve above we show the I-band data available for the source. As one can see, the source is another example of an extremely large amplitude object. It has changed its brightness by about 2.5 magnitudes during the last three observing seasons. Some of these changes have occurred very quickly, e.g. the currently ongoing drop in brightness visible on the far right of the plot.
It is not yet clear if these changes are caused by accretion rate changes or variable extinction. In part this is due to a lack of colour information because the source is quite faint at shorter wavelengths. We will keep an eye on this field and try to obtain the colours as well as to see what happens to this source in the future – stay tuned.