Affiliation
American Association of Variable Star Observers (AAVSO)
Mon, 07/15/2013 - 13:50
U Aqr remains extremely faint. This is an unprecedented fading event similar to R CrB's, where we are witnessing the longest and deepest fading events in the recorded history of these stars.
Yes, U Aqr, an oddball star if there ever was one. I recall that in my early years with AAVSO U was classified as a Mira-type variable (according to our charts and the GCVS) and the AAVSO's lightcurve spanning the 1920's to the 40's did indeed suggest some sort of rather long, but cyclic period.
Nevertheless, I had looked over the star's later lightcurve (1950's and 60's) at HQ and made mention to Director Margaret Mayall that the pattern of variation was just too odd and U Aqr had to be something other than a Mira star. Around that same time some paper, or other, surfaced suggesting that U might, in fact, be a strange R CrB-type star. Early in the course of the AAVSO Circular I called attention to this and urged observers to add U Aqr to their programs (it had been under-observed during the late 60's). The AAVSO's chart was revised and observations increased. This was welcome and it quickly became clear that the variations were anything but Mira-like.
Throughout the 1980's and 90's the star went through a very protracted bright phase. This was followed by the onset of a new period of great activity culminating in the "great deep minimum" it is experiencing currently. I must say that this is one occasion when I'm truly grateful to see the work of our CCD observers, as U Aqr is far beyond the range of any of our visual people these days.
BRJ
[quote=BRJ]
I must say that this is one occasion when I'm truly grateful to see the work of our CCD observers, as U Aqr is far beyond the range of any of our visual people these days.
BRJ
[/quote]
Not beyond everyone's visual range, John. I see several visual points in LCG during its current minimum, and I have glimpsed it several times when its above mag 17 in my 20". I haven't estimated it in this range due to sequence issues though.
Large Dobs are fairly commonplace in the amateur community, but I remain surprised that hardly any visual VSO observers use them!?
Another point I would like to make - even though these stars may be in some kind of "historical" "extreme" minimum now, we must understand that human observations of these stars have only covered an infinitesimally short span of their lives!
Mike LMK