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This 12th mag transient in Vul recently posted on CBAT Transients page:
http://www.cbat.eps.harvard.edu/unconf/followups/J20210770+2914093.html
Amplitude is 9 mags
Here’s the field. I get it around mag 12 (unfiltered re Gaia G) and a position of 20:21:07.71 +29:14:08.9 (Gaia DR2).
A Low resolution (R~500) spectrum taken just now (20210716.915) shows strong H Balmer P Cygni profile emission lines with a velocity of ~1400km/s and other broad emission lines including He. (Looks like it is a Nova)
https://britastro.org/specdb/data_graph.php?obs_id=10094
Continuing to take spectra.
Robin
Further confirmation as nova: https://www.astronomerstelegram.org/?read=14793
I’ve just seen it visually at mag. 12.0 on Jly 16.948 UT, It’s a very red field, so poor comparison choices (high B-V).
Gary
EDIT July 18: With the release of the AAVSO sequence, the above magnitude of 12.0 should be revised to 12.3. Fortunately the AAVSO selected the same comparison star I used, but with a slightly fainter value.
Gary
Spectra from the past two nights. (The first predates the one in the ATel by 4 hours) I have marked the main lines but there are a few currently unidentified. Suggestions welcome
Hi Robin,
As I just posted in reply to your question on the ARAS Forum, I think these lines are C II which are seen in He/N novae.
This spectrum was recorded last night 17th July with a LISA and calibrated in absolute flux using the concurrently measured V magnitude of 13.10.
David
Thanks David. Excellent reproducibility between our spectra taken less than an hour apart though my ALPY spectrum (in pink) is lower resolution of course.
Cheers
Robin
After a drop in brightness in the first 24 h, the nova has been at ~mag 13 the last 3 nights. Not much of a light curve so far as we are in the early days of this eruption. Further observations are encouraged.
The nova is about 0.3 mag brighter tonight (July 20) than it was yesterday. My unfiltered photometry is around 0.4 mag brighter than V band since the nova is so red but the trend is pretty clear. Of the other novae around V1405 Cas is brightening again although still around a magnitude below its brightest and V1674 Her is very gradually fading after its initial rapid decline.
Yes, definitely a bit brighter last night, Nick: ~0.25 mag brighter on Jul 20 in CV for me compared to 24 h earlier.
There has been significant evolution in the spectrum, the He I N II C II lines being replaced by Fe II lines as the classification Atel suggested might happen
Cheers
Robin
Awful seeing last night, haze and patchy cloud, managed to get 1 visual observation with my 10 inch which I’ll upload late. Weather forecast doesn’t look good for the next couple of night. Skies around here Risca just outside Newport in Wales do have a lot of light pollution
The evolution to an Fe II type nova as I highlighted in my spectrum from 24th July has now been confirmed
https://www.astronomerstelegram.org/?read=14816
Cheers
Robin
Interesting to read that ATEL. I’ve managed to observe it on 12 of the 14 nights since discovery and my unfiltered photometry shows it still rising as of last night.
CBET 5007 has designated this as Nova Vul 2021 = V606 Vul. To quote: “R. Leadbeater, Wigton, U.K., writes that a low-resolution (R about 500) spectrogram taken on July 16.915 UT (instrumentation not specified) shows strong Balmer lines in emission showing P-Cyg profiles with an estimated velocity of about 1400 km/s, adding that there are other broad emission lines including He; the spectrogram has been posted at website URL https://britastro.org/specdb/data_graph.php?obs_id=10094.”
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