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Nova Vul 2021

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Jeremy's picture
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Nova Vul 2021

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

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Here's the field. I get it

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).

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transient

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

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Spectrum

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

 

 

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Low resolution spectrum

Just had a quick look at the object through the objective prism and as Robin has shown above there are strong H alpha and beta emission lines.

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Further confirmation as nova:

Further confirmation as nova: https://www.astronomerstelegram.org/?read=14793

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Nova in Vul

I saw it visually on 16. july 22.30 UT. Mag about 12.

Lars

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Chart

There is an AAVSO chart and sequence here.

You can re-scale and re-orientate to your liking here.

Robin Leadbeater's picture
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Spectra

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

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Nova Vul 2021

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

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reproducibility

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

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Currently ~mag 13

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.

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The nova is about 0.3 mag

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. 

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Yes, definitely a bit

Yes, definitely a bit brighter last night, Nick: ~0.25 mag brighter on Jul 20 in CV for me compared to 24 h earlier.

Jeremy's picture
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Continues to brighten

Continues to brighten gradually:

Robin Leadbeater's picture
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spectrum evolution

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

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Nova

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 

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Evolution in spectrum to Fe nova confirmed

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

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Lightcurve

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.

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nickjames's picture
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V606 Vul

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."

Robin Leadbeater's picture
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CBET 5007

Hi Nick,

I guess that is Nova Vul 2021 not 2001. Is that from Dan Green ? I wondered why he was asking about my instrumentation this afternoon. He must have posted it before I replied

Cheers

Robin

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Nova Vul 2021

Yes, 2021! Corrected and Yes, the CBET is from Dan Green.

Robin Leadbeater's picture
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further significant evolution in the spectrum

The spectrum has changed significantly in  the past few days. Except for a relatively weak narrow H alpha emission, all the other lines previously in emission are now either missing or in net absorption.

Cheers

Robin

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further spectral evolution

The H alpha emission line has weakened further and is now showing a P Cygni profile (velocity ~600km/s). The rest of the spectrum now resembles that of a G/K star photosphere but with some additional absorption lines, particularly in the red at ~7106/7766 A  (The other features in that area are Tellurics)

Cheers

Robin

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Fading

Significantly fainter in the spectrograph guider tonight and the spectrum has changed completely once again with a host of strong broad emission lines appearing.

Robin

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Nova Vul 2021

Last night, 3rd August, I measured Nova Vul 2021 at V=10.97, B-V=1.14, almost a magnitude fainter than 48 hrs before and slightly redder. As Robin said, there has been a big change in the spectrum over recent days.

The following LISA spectrum (R~1062) was calibrated in absolute flux using this V magnitude and response corrected with the B9III MILES star HD192907 recorded at the same airmass as the mid-time of the nova spectrum. H-alpha has a strong P-Cyg absorption dip at -320 km/s which now falls within the much broader ~3000 km/s FWZI of the line. FeII multiplets 42, 49 and 74 are prominent with just-resolved P-Cyg dips. There are also emission features at ~5526A, ~5662A and ~7117A, all with P-Cyg dips, which I have not been able to identify in the WIlliams list of nova emission lines. Suggestions?

David

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excellent agreement

Again excellent agreement with mine ~2 hrs later (using a different MILES reference star HD192640) though the the blueward absorption in the H alpha line is not resolved in the R 500 ALPY spectrum 

Robin

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Nova Vul 2021

The nova is still about mag 11.

Here is a picture taken tonight about midnight here  (UT + 2)  14" sct + Canon 77d  10 sek.

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Last nights image from iTel 18: V mag 11.5

Got a series of seven 60 s images from iTEL 18 in Spain last night 2459431.46 . Airmass of about 1.016.

All seven are around 11.47 V mag using Vphot and AAVSO comp stars.

This is a bit of a fade over the last 2 days.

Stewart