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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 2016
That post egress brightening and subsequent drop is most intriguing Max. Testament to the high quality of your data
Great stuff, Max.
Probably flickering, as you suggest Max. All very interesting
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.
No problem submitting, Max. Researchers can subsequently apply any data quality selection criteria they wish. Without any data they have no choice. The other consideration is that your data, at the very least, provide a snapshot of the system status at that time.
Those data really are incredibly tight, Max!
Multiple confirmations of the eruption have appeared overnight. Appears to be around maximum (8th mag).
In the 2010 eruption, it faded one mag in a day and 6 mags in 4 days. Let’s hope we get a break in UK skies (I’ve not seen any UK obs yet)
Can be scaled/orientated to choice
Maehara-san (Okayama, Japan ) reports U Sco at mag 9.2 on
Thanks Max. Good to see you back!
Great stuff – thanks Max
Not sure Max. Does the main dip coincide with the time when an eclipse should have occurred?
Super – many thanks Max. All very interesting indeed.
Impressively tight data, Max!
Worth looking for quiescence eclipses, Max. Accretion disc might be smaller then and thus more easily eclipsed
Yes, mag is certainly consistent with an outburst Max
This nova is still being observed and still relatively bright at 11th mag. Worth following. What will it do next?
Light curve from the VSS database:
Thanks Max. When I have a moment I’ll put it through Peranso to see if there are any signals.