Wed, 12/27/2017 - 09:00
This UGZ type appears to be beginning a standstill phase over the past few weeks. It might be an opportune time for someone interested in researching these behaviors in more detail!
Mike
File Upload
HL-Cma-stand.jpg103.87 KB
Hi,
will put this star back in my observing schedule.
Josch
Thank you Josch, I see your prior photometry was pretty accurate. I thought this target may be quite challenging for CCD, given the background glare from Sirius!
Mike
Looks like some more observations have been coming in, and its still holding very steady at 12.1V, going on 4-5 days now.
I think it would be very interesting if someone could get a spectrum of this during standstill and compare the differences with normal outburst cycles? However, I am not technically knowledgable enough about the process, to say if the light contamination from Sirius would make this accurate or doable?
Maybe multi-color photometry could be interesting too?
Mike
Hi all
I'm surprised how little info I can find about previous HL CMa stadstills (nor much sign of the Z Cam campaign.) Any ideas on a reference?
Best
Alan, have you read Peculiarities of the Accretion Flow in the System HL CMA
(c) 2016 г. A. Semena *, M. Revnivtsev, D. Buckley, A. Lutovinov, H. Breytenbach
accessible at https://arxiv.org/pdf/1610.00874.pdf. Most of it's beyond me but I did note the following on p10:
"Subsequently, periods of prolonged intermediate states were detected in the system, which transfer it to the class of so-called Z Cam systems(Mansperger et al., 1994),characterized by a high accretion rate. "
The authors describe how this 'prolonged intermediate state' happens.
Stephen [HSP]
New Zealand
Alan, do you mean this?
https://sites.google.com/site/thezcamlist/the-list/hl-cma
The paper I mentioned above came out after the HL CMA page was done.
Stephen