2025-02-12 T CrB update

T CrB update

https://www.astronomerstelegram.org/?read=17030

Il semble bien que l’intensité de la raie H_alpha augmente sensiblement depuis l’été dernier !

Which my Français-de-chien translates as "It seems that the intensity of the H_alpha line [in the emission spectrum] is considerably stronger now than last summer. Which was specifically one of the things Schaeffer was mentioning as needing close monitoring in his alert of 10 months ago. It hasn't "gone" yet, but that's what would be expected in the run-up to an outburst.

Merci beaucoup à Alain Lecacheux at [PSM observatory], Alain Figer, Al Grycan and Jean Lecacheuxfor the "heads-up!"

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Further update

https://www.astronomerstelegram.org/?read=170410

Overall, given the rapid and drastic increase in intensity and width of the Hα profile, we strongly anticipate that the T CrB outburst may occur soon.

Spectroscopy on Jan 15, 29 and Feb 07 continue to show rapid increases in the H_&aplha; line, in both intensity and width (indicating a larger size of the accretion disc).

In other words, thinga are hotting-up.

Similar changes have been observed in other "cataclysmic variables" in thye run-up to recent outbursts, though none have the historical record of reaching naked-eye visibility that T CrB has. You probably won't need to carry sunglasses all night, unless you're wanting to pose.

I don't see other mention of T CrB in other ATels back to mid-January.

Wait, what's this? T CorB

Has T CorB "gone"?

I checked recent results from AAVSO at about 17:30 local time.

Star	JD	Calendar Date	Magnitude	Error	Filter	Observer
T Crb	2460647.06597	2024 Dec. 02.56597	<6.0	0.1	V	HQA
T Crb	2460647.03	2024 Dec. 02.53000	9.8	-	Vis	BRG
T Crb	2460646.96597	2024 Dec. 02.46597	<5.6	-	Vis	TRIB
T Crb	2460646.45344	2024 Dec. 01.95344	11.341	0.0048	B	DEY

Inevitably, we're under 8/8ths cloud cover here.

18:10 (JD 2,460,647.26182) Not managing to get an updated measurement listing. But that's a fifth of a day ago. (0.19 JD), 4 and a bit hours. Is there a problem in the hardware?

My "Astro-COLIBRI" is reporting an "unclassified optical transient", but that's at a Dec of 31.57° N, which is … actually, that is in the right range (25~35) for the constellation. But T Corb is at dec 25.9°, so … I'm going to have to convert between RA systems.

OK,converter written, the optical transient ("AT2024addv") was only 5 degrees off in declination - which is a plausible error, but 36° off in right ascension, which is not a plusiible error. But the AAVSO website hasn't posted any more results as of 19:15. Then Firefox crashed. [SIGH]

Anything on other astronomy news sites? S&T? Nope. Astronomy.Com ? nope. CBAT ? Nope.

Has T CorB "gone"?

It looks like that was just a glitch - some blockage in AAVSO's pipeline just while the brightest magnitude readings had been posted for ages were at the top of the list. Overnight postings eventually went back to the norm of around 10 mag (Vis). Which is what you expect, but in this case we're poised for a rapid rise cataclysmic eruption.

Oh well, I got one bit of necessary stuff built into my worksheets. Now need the reverse function.

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