This week we don’t look at a young star, but nevertheless an old friend of the project. Many years ago we found an unusual variable in the Elephant Trunk Nebula field. It stood out from the others in that it got redder when it brightened during an outburst. It took us several years to work out that it was not a young star but an erupting Be type star in the background. By that time we found another, similar object in the Gaia data – Gaia19eyy.
All the data and our interpretation of it got published in a paper last year – A survey for variable young stars with small telescopes: VI – Analysis of the outbursting Be stars NSW 284, Gaia 19eyy, and VES 263. The Gaia19eyy source seems to show regular bursts every 390 to 490 days. These burst are usually just under half a year long. The last detected burst of the object started about 500 days ago, thus we had a look at the light curve to see what is going on.
And ….. nothing happened. Since the last burst the light curve has been “flat”. In particular the V and R-band data show no variation other than the photometry noise. In the I-band, there is a small brightening trend visible over the last month. The amplitude is of the order of the photometric noise, just a few percent. But it is clearly visible. This could be a sign of the next burst, which seems to be overdue, now finally starting. Unfortunately the source is getting close to the Sun and is imminently entering its few months were it is not observable. We might just find the source in its bright state when it becomes accessible again and can’t follow the brightness increase this time. However, if not, then this will be the longest known gap between burst we have seen. Let’s check in a few months…..