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A submission to the PASP today considers the “Legacy of Henrietta Leavitt: A Re-analysis of the First Cepheid Period-Luminosity Relation”:
https://arxiv.org/abs/2502.17438The authors re-analyse Leavitt’s first Period-Luminosity relation using observations of the same set of stars but with modern data and methods of Cepheid analysis. They go on to consider the discovery of two types of Cepheid populations and the implications for Hubble’s measurements of the distance to our neighbouring galaxies.
I will touch on this topic at the Deep Sky Section meeting, as two key Type II Cepheids were actually discovered in 1890 by David Packer, who for many years was a BAA member living in Birmingham.
This conference paper examines the recent debate about phosphine and other potential biomarkers in Venus’ atmosphere and whether cosmic rays might actually destroy chances of life (they conclude they don’t, but this is based on cosmic ray simulations rather than actual data): https://arxiv.org/abs/2502.13371
This AJ preprint on ArXiv predicts that T CrB will become the brightest nova ever observed in X-Ray: https://arxiv.org/abs/2502.10925
The authors also discuss the future evolution of the white dwarf towards the Chandrasekhar limit.
Cloud in Yorkshire? Whatever next!
Seriously though, another fascinating album. I presume “Collinson” was EH Collinson, who joined the BAA in 1920 and had gone to school in Yorkshire.You might want to start a new thread with your de-forking question, Ken.
There is an old thread here which includes a reference to Martin Mobberley’s JBAA paper (though the link is corrupted):
https://britastro.org/forums/topic/meade-lx200-classic-telscopeFascinating, David. Thanks for sharing.
Not sure BAA members would Don those eclipse outfits today!I always find such scenes from the years leading to WW 1 highly evocative
An ATel today reports an increase in accretion rate in the last couple of weeks: https://www.astronomerstelegram.org/?read=17030
What a splendid short film. Thanks for sharing this, Richard.
I wonder what else John Goodricke might have accomplished has he lived longer.In answer to a question following my talk on T CrB, I mentioned that some had predicted that the neutrino burst from the eruption might just be detectable on Earth. However, a pre-print on ArXiv today suggests that the burst might actually be too weak for such a detection.
As ever, time will tell.
Another analysis of the recent great dimming of RW Cep is appears in an A&A pre-print on ArXiv, “Atmospheric dynamics of the hypergiant RW Cep during the Great Dimming“.
The authors present spectroscopic observations which reveal changes in the star’s atmospheric dynamics during the fade. It is interesting to see they cite Robin Leadbeater’s analysis published in the VSS Circular.
Michael Woodman, who independently discovered the 1946 eruption of T CrB as a 15-year old schoolboy in 1946, was guest of honour at the BAA meeting on January 18. He was presented with the BAA VSS Charles Butterworth Award.
Many thanks to all those present who helped to make it as special day for Michael and his family.
A photo of Michael (taken by Philip Jennings) is attached.
Attachments:
Article on “A Predicted Great Dimming of T Tauri: Has it Begun?“ here
https://arxiv.org/abs/2501.06378An AJ preprint from Tracy L. Beck (Space Telescope Science Institute).
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
