This weeks object is LkHa148. It is topical, since it has been announced as a Gaia photometry alert yesterday – showing a 0.6mag ‘outburst’ two days earlier (Sunday afternoon, 30.08.2020). As it is in the Pelican Nebula region, we could immediately check what is going on and put things into context. The star itself s a know emission line star. Its Gaia parallax puts it right into the star forming region. The spectral energy distribution shows a clear infrared excess, i.e. there is evidence for an accretion disk.
Our HOYS data in the V-Band (the closest to the Gaia band) shows that the star generally varies by about half a magnitude, more or less randomly. There is also a general long term trend with a minimum about three years ago. The Gaia data kind of mimics this and shows another ‘hump’ about 4.5yrs ago, which we also see in our data. However, our much better sampled data puts the variations into context, indicating that about 0.5mag variations happen all the time.
Looking just at the last ~200days, we clearly see the same ‘burst’ that Gaia detected in our data. The last three V-band data points are taken Monday night and Tuesday night. Hence, yes, there has been a 0.6mag brightness increase which is now declining. But overall, these things happen often and are nothing special for this particular source. It is just the first time that Gaia caught one of these due to its rather sparse sampling.