Affiliation
American Association of Variable Star Observers (AAVSO)
Thu, 02/25/2016 - 16:22
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.
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.
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!
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
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
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
Another interesting paper just issued, read here:
https://arxiv.org/abs/1807.01304
Clear sky to you all
Michel