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I see the dilemma, Max (also shows rage pitfalls CV observers can get into with less than ideal data). If you can confidently and consistently compensate that would be the way to go (sorry!). In any case, it would be important to identify those eclipses where there is some kind of uncertainty in assignment of type.
Interesting to see JWST papers already appearing: https://arxiv.org/abs/2208.01630
This one on flattened disc, reddened galaxies.
No doubt a trickle will soon become a torrent
They may even be a fraction deeper that’s the last pair, Max. Asymmetric, as before, as you noted, perhaps steeper entry…
Would need to think about that Max 🙂
It’s great fun having these speculations. We’d probably not be in the position to do so with your intense and precise data.Superhumps are characteristic of a DN superoutburst. There are indeed caused by the AD becoming elliptical. So there would need to be a series of humps, the period of which would be slightly longer than Porb. Have you measured the “hump period” to check that it is consistent with the eclipse period?
Those data are truly remarkable regarding their precision, Max. I suppose technically this is a bright outburst (no superhumps modulated with the Porb, which is too long to be a UGSU system).
I wonder if there is any way of probing (or estimating) how much of the disc goes into outburst. There is an idea that only part of the AD goes into outburst, resulting in these “stunted” outbursts. I therefore wonder if the eclipse width of this bright outburst is wider. Or perhaps this current outburst is a “normal” one, like the one 5 outbursts ago at the beginning of your second plot above, the intervening 4 being “stunted” outbursts……
I can’t believe its almost a year since the RS Oph eruption!
An MNRAS pre-print on the “Study of 2021 outburst of the recurrent nova RS Ophiuchi: Photoionization and morpho-kinematic modelling”, on ArXiv today, presents the evolution of the optical spectra of the eruption, includes amateur spectroscopy and photometry: https://arxiv.org/abs/2207.10473
In common with its CV brethren, CG Dra is determined to keep use guessing, Max!
Thanks for posting the LC showing the series of recent outbursts.Looks like you are extracting lots of interesting details and features out of your data, Max. Great to see!
I think the long term light curve covering multiple outbursts will be a good probe of how the AD changes, especially at the beginning of an outburst. That is the advantage of studying a system that outbursts so often. I say “outburst”, although it is by no means clear these are traditional DN outbursts (they are quite small and their profile is different).
A paper by Brad Schaefer submitted to MNRAS appears on ArXiv today: https://arxiv.org/abs/2206.14231#
It describes a missed eruption of U Sco in 2016That post egress brightening and subsequent drop is most intriguing Max. Testament to the high quality of your data
Changes in periods of Miras is a very active field of research as it might shed further light on stellar evolution in the Asymptotic Giant Branch (AGB) of the HR diagramme. One popular view is that period decrease is due to contraction during the initial stage of the thermal pulse in the helium burning shell, as you indicate.
Another period changer is T UMi. Coincidently there is an MRAS pre-print on ArXiv only today on “Hydrodynamic modelling of pulsation period decrease in the Mira-type variable T UMi” which pursues the matter. It considers hydrodynamic models and non–linear stellar pulsations. The references therein are worth following: https://arxiv.org/abs/2206.08360
Keeping up with ideas and literature in this area could be a fulltime job, but we are lucky to have the monthly AGB Newsletter to help us as it summarises recent literature. You can subscribed to it here: https://www.astro.keele.ac.uk/AGBnews/
The June edition is the 299th, and celebrations are promised for the July edition. It is available here: https://www.astro.keele.ac.uk/AGBnews/issues/AGB299.pdf
The last chapter on this fascinating topic has yet to be written! But it is interesting to note that the research, and the associated models, depend on amateur observations of Miras over many years.
