T CrB before its new nova event

[Matthieu Le Lain]

Hi all,

Here is a new spectrum of T CrB with an alpy on C8 (24/03/2022)

T CrB - 24/03/2022

Matthieu

[Joan Guarro Flo]

Hello,

That's T CrB from the SMM remote Observatory this last night.

Regards, J. Guarro.

[Francois Teyssier]

Good!
The campaign is restarted after the (too long) seasonal gap
The last spectra show a fast decline of He II line toward 0 in low resolution spectra and very faint in echelle spectra.
This sudden fading after a long decrease could be a clue of the entrance of the system in the last phase before the nova outburst.
A page summarize the current status and the monitoring. It will be updated weekly.
http://www.astronomie-amateur.fr/Erupti ... TCrB0.html

A cadency of 2/3 spectra a week is suggested.
The behavior of the recurrent nova *before* the outburst may provide informations at least as important tahn the nova event in itself.

All the best and thanks in advance for your involvment.

fmt

[Francois Teyssier]

Detection of strong flickering by M. Minev, R. Zamanov, K. Stoyanov (Institute of Astronomy and NAO, Bulgarian Academy of Sciences)
https://www.astronomerstelegram.org/?read=16023
The flickering increased compared to the last published values (my work)
stronomerstelegram.org/?read=15916
and graph: http://www.astronomie-amateur.fr/DUAO/T ... ering.html

M. Minev+ conclude by the question: Does it mean that the super-active state is over?
The increase of the flickering coincides with the sudden fading of He II.

http://www.astronomie-amateur.fr/Erupti ... TCrB0.html updated

[Christian Buil]

Alpha evolution at high spectral resolution (instruments from 4 to 8 inch + Star'Ex HR, on ZWO AM5 mount) :



C. Buil

[etienne bertrand]

Un spectre de T Crb au LhiresIII

[Joan Guarro Flo]

Hi there,

This is a T CrB graphics from the SMM Remote Observatory in this bad weather season.

Cheers, J. Guarro

[Guillaume Bertrand]

Here's a new spectrum of T CrB with my little 72mm refractor. (A bit of a challenge ) In red, for comparison, a spectrum from a year ago.

Cheers,
Guillaume

[Christian Buil]

A high-resolution Star'Ex spectrum (R=19 000) made on June 13th from Antibes and like Guillaume B, using a small diameter, here an 80 mm Askar scope (model PHQ), all on an AM5 mount, and managed via ASIAir (except for the spectra storagel under Prism):



Full observed range :



The intensity of the Halpha line is still falling, while the star remains blocked at magnitude V=10. How far will this Halpha line go...

Christian Buil

[Francois Teyssier]

Yes, the spectrum returns to the pre-high state aspect: the continuum is dominated by the M4 III red giant. The emission lines becomes fainter (even if He II and He I are still present)
During the two last months, the EW grew a little bit according to orbital phase. But the global trend is decline.

First low res spectrum in the database, more than 10 years ago.

asdb_tcrb_20130217_146.png (52.02 KiB) Viewed 9568 times

Guillaume's comparison shows the decline observed during the last months.
But a word a caution: the flux and profiles of the lines are strongly dependent of the orbital phase. Thus the most accurate comparison should use spectra acquired at the same orbital phase



This is a key point of the symbiotic stars monitoring: long term and high cadency observations can produce very valuable results
It needs much more abnegation than short observing campaigns.
This is my conception of the contribution of amateurs to the community (in fact exactly the same state of mind as in photometry since one and half century)
And it is very appreciated by number of professionnal teams working on eruptive stars.
Our T CrB dataset (more than 760 spectra in 10 years) is a treasure for the research (even if it raises more news question than it solves !)

I'm working on a presentation for the SAS 2013 symposium. It will be ready next week.

Bonne continuation! Keep on the very good job!
François