This week we have a look at an old friend of this feature, the variable V350Cep in the NGC7129 cluster. Since it’s 4mag brightness increase in the 1970’s the object has roughly remained at its bright state. We have looked at it in early 2022 when other than a short dimming event (where it got flagged up as a Gaia alert) nothing much happened. Just some gentle long term, low amplitude changes.
Since two years now the source has changed its behaviour. It has started to show longer term erratic dimming events of up to 1.5mag depth. We looked at these in weeks 269 and 289. With the worst observability for the source approaching, we have a look what has happened in the last ~6months. We show the last ~2yrs of data (in the B,V,R,I filters) for the source.
The dimming event(s) is still ongoing. The source remains 0.5-1.0mag fainter than in it’s ‘normal’ bright state. The short term (<1week) fluctuations have reduced to the level seen in the older data and the light curve hence looks much more smooth. The erratic short term variations seen about a year ago have mostly stopped. We’ll keep an eye on the system to see what happens next. Do the fluctuations continue? Does it return to it’s ‘normal’ bright state or even back to it’s pre-outburst brightness – and disappear from our survey as it would be far too faint….