This week we stray away from the usual young stars and have a look at an old star instead. It is situated in our only far southern field, near the object Gaia19eyy – we are making good progress on writing up the paper on that source.
The star in question is called IRAS 08303-4112. It has been classified as a long term variable in the ASAS-SN survey. It looks quite red in the images, and the Gaia parallax places it at a distance of about 2kpc. Thus, in combination with it’s light curve, it is most likely a pulsating giant star. These objects are fun to follow, as they vary usually nice and smoothly, but for many of them one cannot really predict far in advance what they will do – note this is of course not the case for the periodic pulsators like RR-Lyra, Delta-Cep, or Mira type sources.
In the image we show the V-band data for one observing season of the object. As one can see, there are smooth variations with peak to peak variations of 0.1 to 0.2mag. There is no clear period and there are also underlying longer term trends. You may see that in places the data seems to scatter much more. Our off-line additional calibration will most likely be able to remove some of that and make the light curve even smoother. The data shown, is straight from the data base, the same what is available via our website.