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Is there an LPV which ceased to vary?

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capricornus's picture
Is there an LPV which ceased to vary?

I seem to remember reading many years ago - probably in 'Burnham's Celestial Handbook' - about a long period variable star which had behaved normally for many decades but had then stopped pulsating altogether. Am I remembering this correctly, and if so, which star was it, and what has it done since Burnham's was published (back in the mid- or late-1970s)? Thanks!

Matthew Templeton
LPVs that change behavior

I seem to remember something similar, but I can't remember the exact star.  There's a short list of stars in Mattei, Mayall, & Waagen's Maxima and Minima of LPVs, 1949-1975 (published 1990) whose behavior had changed enough to make predictions difficult: W Tau, RT Hya, Y Sco, and SZ And.  It is possible that these are simply semiregulars whose (possible?) multiperiodic behavior was simply at a phase where the different periods were interfering destructively, leading to a drop in amplitude.  I checked all of these stars, and they're still pulsating with detectable amplitude now.  T UMi is a similar star, but its notable that it was a Mira and became a semiregular within the past four decades.

Polaris isn't an LPV (it's a delta Cephei star) but its amplitude dropped away to almost nothing for several years and subsequently started to increase again.

HQA's picture
LPV that ceased to vary

I don't know of any LPV that has ceased.  What you might be thinking of is RU Cam, a 22-day irregular variable commonly classified as a CWA type.  This star ceased variation for a number of years in that 1970 timeframe, and might have been reported in Burnham's.  As Matt mentioned, Polaris nearly ceased pulsation, but was not reported as changing its amplitude until a paper by Ferro Arellano in 1983.


HJZ's picture
Is there an LPV that ceased to vary

Maybe we should query Ed Guinan.  He seems to be leading the charge for the AAPVSO - the american association of (previously) variable star observers. 

MDAV's picture
Star which ceased to pulsate

Hi all:

That was RU Cam in Burnham Vol I. -a Cepheid. which apparently ceased to pulsate around 1971.A quick check of the LCG shows the apparent cessation but at the scale I looked it wasn't that clearcut.

Some LPVs have certainly changed their periods and I read an article few years back that suggested Mira underwent a Helium shell flash near the time of its discovery. R Hya was another but there were some challenges to the Shell Flash model v Envelope relaxation.


Dave M

dquig's picture
Z UMa Ceased variability for

Z UMa Ceased variability for arounf 1684 days. Ive attached a graph of the light curve and weighted wavelet transforms in 1634 day windows. I've just finished a project on this so if you'd like more information please get in touch.


dquig's picture
Also here's a graph showing

Also here's a graph showing how the two modes developed with each other the red is the longer 194 day period and the blue th 97 day one

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