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An A&A preprint on ArXiv today discusses the recent super-active phase SAP of T CrB.
The SAP lasted between 2015 and 2023, during which T was about three-quarters of a magnitude brighter than normal. A similar SAP was observed prior to the 1946 eruption.
The authors find that the SAP was triggered in the inner part of the accretion disc, increasing the disc temperature and the mass accretion rate at the white dwarf surface. The higher temperature should have further enhanced the mass transfer and sustained the SAP.
The SAP abruptly stopped in 2023, implying that the disc has returned to a quiet phase. At this time accretion dropped to a very low level. Recently T has been gradually brightening again and accretion has picked up. Note that when sufficient material has accumulated on the surface of the white dwarf, it triggers the thermonuclear runaway that appears as a nova eruption.
Generally a very poor year for me. Weather and frequent travel combined.
I made 2217 individual VS CCD observations.Andy Wilson’s report on the VSS database in the October Journal lists the most observed stars in the last session. T CrB was top.
For visual observers the top 3 were: R CrB, T CrB, SS Cyg
For digital: T CrB, SZ Lyn, SS Cyg
For spectroscopic: T CrB, BE Lyn, TX CVnMichael Woodman was interviewed on the BBC World Service news this morning about his discovery of the 1946 eruption of T CrB.
I have invited him to attend the January BAA meeting to receive the Charles Butterworth award of the VSS.
Hello Bill,
I use LiFePO4 batteries from Tracer: https://tracerpower.com/products/product-category/batteries/
It all depends on how much power and for how long you want to use. I have 8 and 16Ah Tracers.
I also have a Tracer Li-polymer battery but it is not really up for my AZEQ-6. Hence why I switched to LiFePO4.
Jeremy
Confirmation via ATel (no doubt there will be more over the next days): https://www.astronomerstelegram.org/?read=16944
Bad luck Eric. Hopefully you can catch it tonight. Given how short the eruption is, every obs counts.
The recurrent nova M31N 2008-12a’s ~annual entry onto the stage has just been announced:
2024-12-13.0074 UTC with a magnitude of 18.6 CV, Jingyuan Zhao using the Burke-Gaffney Observatory remotely.Matt Darnley (LJMU) calls for follow up observations over the next 3 to 4 days. This RN fades rapidly. And it is faint, 18th mag at max. Matt has sent a ToO observing request for follow-up observations with Swift.
Well it looks like humps, Ian. But they are pretty small and somewhat irregular for fully grown superhumps. It was also fading quite quickly. I hope you will get some more data.
Looking into the BAA VSS and AAVSO databases, there are fewer obs of this archetypal dwarf nova in recent years. This is a real pity, so it’s good you are following it. Occasionally it does odd things. There have been a few epochs when it stopped superoutbursting, eg 3 years in the 1980s, plus some more recent times. And in 2020 it apparently showed no outbursts at all for ~4 months.
An ApJL preprint on ArXiv today reveals the the discovery of a Nova Super-Remnant (NSR) surrounding T CrB. This is only the third known NSR. It at least 200,000 years old. Turning to the forthcoming eruption, the authors predict there will be no fluorescent light echoes seen after T CrB erupts, but there might be dust-scattered, continuum light echoes during the year following the nova eruption.
On the lighting front, there might be an opportunity to play back Dundee City Council’s own nett zero plan: https://www.dundeecity.gov.uk/sites/default/files/publications/net_zero_transition_plan_2024-2030.pdf
This states that 25% of its emissions are from the electricity used in its buildings sector. This is the second largest contributor (after heating of buildings). As a consequence, their action plan item OE2 is about addressing lighting in buildings (though not OF buildings; I would hope this would be included).
An A&A preprint on ArXiv today might me be interest: Two epoch spectra-imagery of PV Cep outflow system.
The authors describe features in the associated HH object and their kinematics.
They report a newly-formed HH knot, which they presume formed during the large maximum of PV Cep star in 1976-1977.
ATel 16912 on “Continued monitoring of activity in T CrB: Rapid intensification of He II and spectroscopic gyrations” discusses recent spectroscopic changes in data from the ARAS group: https://www.astronomerstelegram.org/?read=16912
The overall significance is not clear, though there does appear to be a change in accretion environment and rate around October.
This is definitely feasible. Arne Henden is routinely monitoring T CrB in daylight. He is using a Newtonian stopped down to 50mm and is able to image theta CrB mag ~4.1. The other day there was a false alarm and he was able to show that there was nothing brighter than mag ~4.5.
The rise time is 1-5 hours.
