T CrB

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)

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

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.

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

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

Another interesting paper just issued, read here:

https://arxiv.org/abs/1807.01304

Clear sky to you all

Michel