T CrB High state

[Francois Teyssier]

An informative paper from Munari & al. http://arxiv.org/pdf/1602.07470v1.pdf
The state of the symbiotic star and recurrent nova T CrB (mag 2 in 1866 and 1946) is decribed as superactive

(1) the presence
of OIV and [NeV] lines and a very strong HeII
4686, a strong 4640 Bowen fluorescence blend, (2) a
large increse in mean brightness, and (3) disappearance
of orbital modulation from B-band lightcurve

Here's a few lines in a spectrum obtained recently

TCrB_Ha.PNG (11.18 KiB) Viewed 10639 times

TCrB_HeII.PNG (13.42 KiB) Viewed 10639 times

TCrB_OIII.PNG (13.24 KiB) Viewed 10639 times

More observations are welcome

François

[Peter Somogyi]

Fresh result from yesterday evening (the 4 x 20 minute was maybe an overkill):

TCrB_20169227_Hbeta.png (27.05 KiB) Viewed 10606 times

I guess the mentioned lines would be interesting at a higher resolution.

- Peter

[Joan Guarro Flo]

Hi:
The T CrB on the last night.
Regards, J.Guarro.

[Tim Lester]

T CrB for Mar 12. Range = 6000 to 7100 Ang at R=9000. Calibrated for flux.

_tcrb_20160312_255_flux_tlester.png (9.63 KiB) Viewed 10512 times

Tim

[Olivier GARDE]

T Crb taken last night with eShel spectrograph (R=11000) after a long period without any observation (very bad weather here in the French Alps)
The balmer serie


[OIII] 5007 Å


and HeII 4486 Å


Very faint target for the eShel spectrograph

[Francois Teyssier]

Nice Spectra Tim and Olivier (Olivier : j'attends ton spectre !) on the difficult but very interesting target
It will be easier when the nova outburst occurs (mag 2 !), just be patient and acquire spectra before the probable event (fews months, few years ?)
All the best,
François

I was on it this morning but lost a lot of time : no stars of the autoguiding mirror (????) .... In fact the Ne/Th mirror was blocked in flat/thorium position
Just a CH Cyg spectrum before sunrise

[Olivier GARDE]

I was on it this morning but lost a lot of time : no stars of the autoguiding mirror (????) .... In fact the Ne/Th mirror was blocked in flat/thorium position
Just a CH Cyg spectrum before sunrise

I have also the same problem resolve by putting some fine oil with a Q-Tip on the 3 brass rods on which the mirror translate.
Ok François I send you my spectrum.

[Francois Teyssier]

Merci pour l'info, Olivier.

[Peter Somogyi]

Got a clean night with a long sleep (= 9 x 20 minute), allowing to produced this:

tcrb_variability.gif (237.09 KiB) Viewed 10373 times

Normalized to 4730-4830A continuum.
Did per-exposure calibration with linear interpolation of 2 ref.stars (PI Ser).
R~1800 (LHires 600/mm 35um slit) + ATIK 414 EXm + 25cm Newton.

Last time I did not see this high variation for the HeII 4686 emission:

HeII_4686_flicker.png (640.83 KiB) Viewed 10373 times

Looks needed to catch some lucky times as most of the time it was not varying that much.

Other features did not seem to vary, even H-beta varied just like 10-20% and maybe the OIII (5007A) if its final drop was not hit by noise or other processing artifact.
Comparing to my previous spectrum, not seeing any other change rather than these shortterm variations.

Cheers,
Peter

[Peter Somogyi]

Hello,

As planned, did a successful overnight serie of 51 x 5 minute - for now with the 150/mm grating, unfortunately somehow focus was not the best (got finally R~500).
In blue, below 4500 towards 4200A it gets totally defocused (however, above 4600A it's yet healthy).

Here is the result:

tcrb_20160403_heII4686_var.jpg (53.13 KiB) Viewed 10264 times

In order to understand the final statistics of relative flux measures I made (around 4921A - wanted to use as an extra SNR reference, however continuum is hard to remove):

tcrb_20160403_4921A_var.jpg (48.87 KiB) Viewed 10264 times

(zeroed in frame@47 the region of 5018A - that was hit by cosmic ray)

Now the final statistics, using IRAF/splot in a semi-scripted manner (= no manual intrvetion, fully reproducible!), of 51 x 5 minute samples:

tcrb_20160403_51x5min_gnuplot.jpg (123.43 KiB) Viewed 10264 times

For all lines (except the blended set of lines around 4640A) was using splot + 'd' deblend + 'g' gauss fit - continuum, on spectra that was previously brought to the common average 3-order overall continuum.
As for the blend, had to use a dummy flux integration: did splot + 'e' interval above overall 0.85 continuum (gauss fit did not give meaningful data).
To me the HeII 4686 looks changing only.
Other smaller features lost in the complex continuum and low resolution.
Balmer and HeI features are almost restful.
Observation started above 60 degree, let over meridian finishing at approx. 70 degree.

Anyone made similar effort at low res (= sleeping over a night), I'd likely process.

Enjoy!
- Peter

EDIT: re-uploaded smaller jpegs