There is a good summary of recent spectroscopic changes in T CrB from the ARAS group on an ATel issued today:
https://www.astronomerstelegram.org/?read=16912
\Brian
1 Like
Hello Brian,
Can you be nice to summarize in a few words for those who can’t no longer read ATel ? Remember my post about Atel a couple of hours ago on the forum …
(I suppose it will be forbidden to post a screen shot of this Telegram here )
Christophe
Note I was on this target maybe 30 min ago, and it was at its normal level of brightness.
The ATel was from Francois Teyssier and others in the ARAS group, with expert help from Steve Shore (now in Pisa, Italy). It summarizes data up to Nov 15 UT. Briefly, they note the spectra are currently similar to other short-lived active intervals since the 1990s. New emission lines are now visible, including forbidden oxygen and (permitted) helium. This is interpreted as a change in the accretion environment and rate.
\Brian
1 Like
Thank you Brian.
Christophe
Now there is a topic worth some discussion but probably not here!
ATel… I guess the question is does anyone at AAVSO HQ have “credentials” to post? I miss the days of the IAUCs and Brian Marsden… Gareth… Dan Green have carried on over the years… not sure of the IAUCs current state.
I see ATel #16337 just lists T CrB photometry, nothing magical there.
@DEY_VAR HQ has a plan in place to validate claims of a potential eruption and announce it to the world. This includes a submission to ATel.
For the record, the validation portion of our plan has been exercised at least 10 times to date.
2 Likes
There is this tentative prediction that the outburst will be around end of March or early November 2025 (or later):
My understanding was that ATel did not accept notices from AAVSO. Has that changed?
Tom
As good as any numerology method can do.
I asked the very question during the AAVSO webinar on the prediction time. Something along the lines of “Was there any relationship with the outburst event times and orbital phase”… but my question didn’t make it into the Q&A queue for some communication issue or something… Glad someone took the time to investigate it.
Loved the effort to observe during the day… nothing like bashing down the doors of astronomy!
1 Like
It not exactly just numerology since the paper suggests a possible explanation: a circumbinary body with a high eccentricity orbit and an orbital period of ~80 years. I estimate that it has V > 16. We will see it JWST detects it:
1 Like
Greetings Jean,
A 3rd body is mentioned in your paper, granted.
Very high resolution spectroscopy is mentioned. Any ideas on the spectroscopy resolution required to see RV changes you expect?
Good luck on the JWST observations.
Jim (DEY)
T CrB certainly has had faster variations in B-V than the expected simple ellipsoidal variation period (1/2 Porb) in B - V. Perhaps a slow decrease in B-V as well over the plotted interval.
Jim (DEY)
If you had two telescope systems which can operate simultaneously. One has an ALPY600 and the other capable is of capturing images with classic J/C filters UBVRI or 3nm Ha, which filter would you use on the photometry telescope?
Please share your thoughts and explain why?
Thank you very much!!
Steve Hoffman - HSTG
If I had such a system… I don’t… Spectrum wavelength coverage would define which photometry filters I would use. So an alternating sequence of the Johnson-Cousins filters (J-C) that cover the same wavelengths perhaps. So probably B, V, B, V, B, V, … at a minimum.
Ic probably doesn’t bring much to the party and Rc doesn’t bring a lot either as it is so wide. I have no experience with U or H-Alpha filters but I would not use H-Alpha simply because your spectra cover the H-Alpha line much better most likely and H-Alpha filters are not super standardized, some are narrower than others, etc. U might be interesting but unless you have a really good quality U filter without red leak I would just stay with the B, V sequence. You might also put a comment in your spectra and photometry data uploads that coincidental data were taken.
Jim (DEY)
2 Likes
Здравствуйте! Я сегодня наблюдала T CrB ночью с 2:30 до 5:00 часов. Звезда переливалась голубым и оранжевым цветом, колебалась, вспыхивала. Я живу в городе Екатеринбург.
2 Likes
Hello and greetings. Keep following it. It is difficult to observe in twilight around solar conjunction time for most of us at mid-latitudes. Those living further north in latitude combined with the long winter nights have better observing possibilities.
Let us know here if it goes into outburst.
Best regards,
Jim (DEY)
1 Like
Здравствуйте, Джим. Сегодня ночью происходило то же самое!
Здравствуйте. Сегодня третью ночь наблюдаю за каким то очень активный объектом. Я визуальный наблюдатель. Объект переливается голубым, зеленым и оранжевым цветом, изменяется размер. Я сняла небольшое видео, очень красивое. Границы объекта неровные. Я думала что это T CrB. Не получается загрузить фото.
I can still observe it both in the evening and in the morning, from ~40 deg North. I just saw it this morning at about 9th magnitude. I am amazed that I can do this. With T at +25.5 and Sol at around -21, T is about 46 deg N of the sun so that helps, but does make it difficult!
2 Likes
If you have a really good horizon and no dome blockages to deal with it isn’t that hard to follow it for another few weeks in the evening sky, until mid-December at my latitude of just under 38N. A few nights ago I was able to get it going into the distant tree line at an air mass 14.5 or so. Must have no clouds too! Good enough to know if going up, ever UP!
Jim (DEY)
2 Likes