Affiliation
American Association of Variable Star Observers (AAVSO)
Wed, 01/13/2021 - 22:58
I was setting up a sequence for W Per and noticed that two of the comp stars also were labeled as New Suspected Variables (NSV). Looking in VSX I see that the variable type for NSV 948 is CST - meaning that this star was formerly suspected of being variable but is not. For NSV 959 there is no variability type or magnitude range. Can I assume both of these stars are constant and use them in my sequence? For my FOV there are only two other comp stars which of which one would be a check, so I'd like to use these two NSVs if I can. Comments? Side question. If NSV 948 is a formerly suspected variable star, why would it have a NSV designation? Perhaps there should be a FSV designation for those cases.
Hi Scott,
See that NSV 959 is also flagged with the N (in grey) and that means non-variable too. So the type should also be CST. Lots of these objects were directly imported from the NSV catalogue and had no type given and they remained untouched. If we were to revise them nowadays we would classify them as CST, but if you see the N, consider it to be the same.
If any of the comparison stars turns out to be variable, we remove them from the sequence and try to find a replacement if needed.
There are still some variable comparison stars that remain to be deleted but we are making progress. If you happen to find any, please report it.
On the other hand, there are a lot of suspected variables that -as you found out- are not actually variable, so there should be no problem with using them as comparison stars. These two stars in Perseus are a good example.
About changing the names, these are kept for historical reasons but your suggestion makes sense.
However, I think that the best solution to prevent people from observing these objects (they may find them in their charts and observe them without checking their status in VSX), or not using them as comparison stars because of them being plotted as suspected variables, is not plotting them on the charts. After all, they are considered as constant so they are not different from any other star. If you want to know the star history you can seach VSX but otherwise, their current status doesn't make them worth of any special treatment.
Something to think about when VSP is redesigned.
Cheers,
Sebastian