Before I was born Bob Kraft explained how T CrB works, and it is not like that animation.

I think ideas have got considerably more detailed than that, with another half-century of work. But yes, the basic idea of accumulating mass onto the surface of the white dwarf remains the same. But - are the stars tidally locked? Does the material land on one point on the star's surface, or is it spread around it's equator? Or further, if their spin axes aren't aligned, and they mutually precess?

Harvard ADS need a better OCR engine for their archive. I had to go back to the PDF to make sense of the linked page. Hmmmm, "

" That puts quite a stringent limit on the total amount of mass transferred across the 1946 eruption. Or rather, the amount which transferred, less the amount blown away in the eruption.

Harmless, but noisy and distracting. Like flatulence.

But yeah, the Arabic influence in Portuguese is a lot stronger than in Spanish, and there are a lot of differences. I can see getting hung up on that.

Plateauing. .. ?

JD 2460430.385620, date 2024 Apr. 29.88562 mag 7.118

JD 2460430.385389, date 2024 Apr. 29.88539 mag 8.835

JD 2460430.385046, date 2024 Apr. 29.88505 mag 11.250

JD 2460430.384698, date 2024 Apr. 29.88470 mag 9.890

Reporting magnitudes above 8.0 has been explicitly discouraged unless you're really sure.

Either someone (observatory code not given above) is going to be very embarrassed, or a lot of BIG telescopes are dropping their metaphorical cookies and slewing to "TOO".

Am I over-cooking one datum? Good question. But ... the discouragement about reporting magnitudes above 8 ... I have to trust the observers to be sane. Hit the "submit" button.

JD 2460430.385620, Date 2024 Apr. 29.88562 mag 7.118

JD 2460430.385389, Date 2024 Apr. 29.88539 mag 8.835

JD 2460430.385046, Date 2024 Apr. 29.88505 mag 11.250

That looks like it has "gone". And I'm going to STOP interrogating the database, because the "big boys" need that access. And that is precisely why I didn't post a direct link into the database. The "Slashdot Effect" may be history, but now is not the time to fry the servers.

The "alert" messages were very explicit about, "chill out below M=8". Someone has hit the Big Red Button.

This one will presumably do that eventually.

Welll ... It is quite sensitive to the mass. And to the metallicity.

Which uncertainties are precisely Why this "close", "well-understood" example is important. If (unlikely) it goes exactly per Group1's expectations. then Group2 will disagree, strenuously.

If (unlikely) the "bang" happens on 2024-05-01.00001, then the disputes will start at. approximately. 2024-05-01.0002.

And, as normal - has it "gone"? JD 2460430.385620 date 2024 Apr. 29.88562 mag 7.118.

OK, has it gone? The alert has talked, repeatedly, about RED FLAGging a brightness above 8.0, and 7.1 is a LOT above 8.0.

Has it "gone"?

I've got to go check. Then STOP interrogating the AAVSO database, because people with jobs to do, have jobs to do. This is why I didn't give a direct link ot the active database.

What were the previous reports? JD 2460430.385389 date 2024 Apr. 29.88539 Mag 8.835 variation 0.006
JD 2460430.385046 date 2024 Apr. 29.88505 mag 11.250

That is very suggestive.

Actually, Wiki covers this. The constellation is Corona Borealis, it's genitive is, indeed Coronae Borealis.

I may have been sloppy in my typing - I know of the convention, but never having formally studied Latin, it doesn't appear in my internal spell-checker.

Now, which Duolingo course to do this evening - Swahili, French (revision), German, Spanish (learning beyond my schooling), or Russian? Oh, I forgot Portuguese - but that's so similar to Spanish that I can function in Portugal already.

This is different from an Ia supernova, during which a neutron star captures enough gas from a nearby star to collapse into a black hole.

That depends on the nature of the underlying white dwarf - it is hypothesised. A CNO (Carbon- Nitrogen- Oxygen) white dwarf is thought to disrupt completely by everything fusing in seconds. A ONe(Mg) (Oxygen- Neon- [maybe Magnesium]) white dwarf on the other hand is thought to disappear down the plug hole of forming a neutron star then (possibly) a black dwarf.

Which is theory - and subject to experimental confirmation. Or disputation. And it looks as if Nature is going to go do astrophysicists (and bomb-designers) the courtesy of doing the experiment for us. And at an un-distressing range too. You probably wouldn't want to do this experiment in, say, the Alpha Centauri system.

Type this, that or the other SNs are spectroscopic and light-curve classifications ; whether they map neatly onto the actual underlying mechanism is another point of theory - subject to experimental confirmation (or disputation). If this event gives the wrong answer ... there's a lot of re-writing of theories to be done. And what did Feynmann say about theories that disagree with experiment?

(There will be so much ink shed over "what was the nature of the precursor in T.CrB?" if it gives the wrong answer. But probably more ink, if it gives ambiguous answers.)

With a (probable ; argued, but not demonstrated) sequence of 10 eruptions for this example, the eruption probably ejects more than 90% of the accumulated mass, but that's me calculating on the back of a thumbnail, not an astrophysicist thinking it through in detail.