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A paper on ArXiv today discusses “Initial Observations of the First BlueBird Spacecraft and a Model of Their Brightness”, https://arxiv.org/abs/2505.05820
“Based on a large set of visual observations, the mean apparent magnitude of BlueBird satellites is 3.44, while the mean of magnitudes adjusted to a uniform distance of 1000 km is 3.84. Near zenith the spacecraft can be as bright as magnitude 0.5. While these spacecraft are bright enough to impact astronomical observations, they can for periods be fainter than the BlueWalker 3 prototype satellite. A model for their brightness shows that design changes since the BlueWalker 3 mission can explain the behavior of BlueBird.”
I hoped they may stick their necks on in the section 4.3 “when will T CrB erupt?”. They observe that “Recent photometric and spectroscopic observations indicate that the system is returning to a high-accretion state. Given this, an eruption may be imminent, even without distinct precursors”. So, as ever, we shall just have to keep on watching as there might be no warning.
An MNRAS preprint on ArXiv today reviews images of the VN since 2017: https://arxiv.org/abs/2505.01760
The paper “Hubble’s Variable Nebula I: Ripples on a Big Screen” describes how they compiled images into a movie which can be viewed here: https://www.youtube.com/watch?v=5QOkzmlSzKI
The RAS has launched a video on observing the Lyrids.
There is something of a gap in coverage at Pacific longitudes. Partly due to sparsely populated regions and partly due to people submitting their observations to other organisations (e.g. Japan). The Philippines seems to be a fruitful area for increasing coverage.
Keep up the good work with your imaging patrol.
A preprint on ArXiv today on the “Red giant component of the recurrent nova T Coronae Borealis” concludes the mag of the red giant is V = 10.17 +/- 0.06
I see at least Space.com put a question mark at the end of their headline and quoted Jeremy’s scepticism (Also the lack of any evidence in the RV data to support the presence of a suggested third body to trigger the outburst on certain dates.)
https://www.space.com/the-universe/stars/hold-onto-your-hats-is-the-blaze-star-t-corona-borealis-about-to-go-boomIt’s nice to see some balanced reporting. And to be quoted correctly 🙂
Not so sure about the third body, though!
Yes it’s a strange claim, Michael. And made with such certainty. Perhaps an example of false precision…
Mind you, if it does hold off until just after midnight tonight, it will be a nice birthday present for me 🙂….and now the BBC has picked it up: https://www.bbc.co.uk/news/videos/cjw2j8e1476o
Pretty impressive sight. I was emerging from my observatory, which has its door on the N side, at saw it as I looked up.
iPhone pic here: https://britastro.org/observations/observation.php?id=20250324_214542_63483fe3de3e8a2eI also caught it on my N facing meteor camera.
Yes this prediction in the Schneider paper was discussed a few posts above (3 March), Dave.
As I said then, I can see no real astrophysical basis for this.The rest of the article is not bad at all. Thanks for sharing it.
The link to Forbes does not work for me. I found it here: https://www.forbes.com/sites/jamiecartereurope/2025/03/20/a-star-may-explode-next-week-in-once-in-80-years-event—what-to-know/
Edit: this link does not work either. The real link, bizarrely and unhelpfully, contains three hyphens in a row which seem to get corrupted into a single long line.
Those of you planning to attend this meeting in God’s Own County, and with time available, might like to see this article on local astronomy haunts: https://britastro.org/journal_contents_ite/an-astronomical-day-out-in-rural-cheshire
Great to hear this development, Andy. I especially look forward to seeing what sort of photometry you can extract.
I would also be interested to hear how faint you can go with different exposures and therefore whether this Smart Scope, or others, might have value in nova searches (where detections by a amateurs using 135mm lenses and digital cameras have been successful).
I’ve started work on the “real time photometric alert script”, I hope I can outrun T CrB … My plan is to have this run on a Raspberry Pi, using siril-cli (for stacking (say) 4 x 10 sec exposures (green channel), Source-extractor (for creating a catalog of detected stars and instrumental photometry), scamp for doing the astrometric solution and some custom scripts to check the photometric results for consistency and generate the actual trigger. We will see…
This is an interesting project, Heinz-Bernd. Keep us posted and if it works out perhaps you can write it up for the VSS Circular.
Good luck!Yes I am familiar with that analysis Steve. I can’t think of an astrophysical reason why there should be a fixed number of orbits between eruptions.
A paper on the “Binary Parameters for the Recurrent Nova T Coronae Borealis” today reports the masses of the white dwarf and the red giant that comprise this binary system. The authors conclude that the WD mass is 1.37 +/- 0.01 M-sun. This would place it close to the Chandrasekhar instability limit.
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.
