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T CrB

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stellakafka
stellakafka's picture
T CrB

Friends,

 

ArXiv hosts a very nice new study of T CrB by Ulisse Munari et al. Especially figure 3, presents the "long term evolution of the brightness of T CrB in quiescence, from 120,000 AAVSO visual estimates collected after the 1946 nova outburst.". Enjoy:

http://arxiv.org/abs/1602.07470  

 

Best wishes - clear skies,

Stella.

VOL
Thank you for pointing this

Thank you for pointing this out -- interesting reading.

T CrB is quite bright the last few weeks. In April it has risen to around 9.3mag. It will be interesting to see whats happening.

Best regards

Wolfgang Vollmann (VOL)

 

ocn
ocn's picture
T CrB

 

Hi All,

This symbiotic recurrent nova continues to be relatively quite bright. It is also substantially bluer than in a number of online (ADS) references I've checked.  One of the more recent, ATel 8675 (2016) reports that T CrB has within the past year or so, entered a superactive state.  

I also note that this famous variable is also quite bright in the U band although our current available field photometry lists only one U-band comparison star, namely the 112 comp shining at U mag 11.946. A U-band observation made just a few hours ago in conjunction with the B and V obs (see our database) gives the following comparative S/N ratios for several AAVSO comps closeby as well as the variable itself giving you an idea of the present scene:  

112 comp snr 023

99 comp snr 035

105 comp snr 052

98 comp snr 057

T CrB snr 260

Is this a workup to 'the big one' ?  Fascinating star with plenty of wonderfully informative references !

Take Care All,

Steve

 

 

 

 

stellakafka
stellakafka's picture
need more data!

Hello Steve,

Thank you for your post. Yes, T CrB *seems* to be doing something unusual, so more observations will indicate whether this is "only" an increase in mass transfer rate (for whatever reason) or something more energetic. Let's see...

 

Best wishes - clear skies,

Stella.

pox
pox's picture
Wow! I was going to take a

Wow! I was going to take a look at T CrB last night, but thought "nah... it'll be about 10.2 again". Not the first time this sort of thing has happened - I should have learnt by now! The clue is in the term, isn't it? Variable Stars!

weo
weo's picture
T CrB in AAVSO Special Notice #415

AAVSO Special Notice #415 discusses the current behavior of T CrB and requests observations. Please see the notice for details.

Many thanks, and good observing,

Elizabeth Waagen, AAVSO HQ

bdg
bdg's picture
T CrB spectrum

Here is a flux calibrated spectrum of T CrB taken last night, 9th April, with a LISA spectrograph on a C11.

The concurrently measured magnitudes of the star were B=10.20 and V=9.34.

The H-alpha emission line flux is 6.6 x 10-11 erg/cm2/s.

Best wishes,
David Boyd

 

FJQ
FJQ's picture
T CrB spectrum

To:  David,

Nice spectrum!  Just out of curiosity, what is the resolution of your grating and the type of software your using to reduce you spectrum data?  I'm on my 2nd spectrum software package, Bass, and would like to know what you suggest.

James Foster

bdg
bdg's picture
T CrB spectrum

Hi James,

The nominal spectral resolution of the LISA is 1000.

I now use Christian Buil's software ISIS to process all my spectra. This has a moderately steep learning curve but it is rich in functionality and once you know what you are doing it only takes a few minutes to reduce a set of spectra.

David

Deconinck Michel
Deconinck Michel's picture
Dramatic change in the boundary layer of T CrB

Another interesting paper just issued, read here:

https://arxiv.org/abs/1807.01304

Clear sky to you all

Michel

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