Nova Tauri 2026 [Posted 20260808]

[Mike Harlow]

The sky cleared just in time this morning for another spectrum. Interesting to note that the feature between H beta and H gamma seen on 25th August has now faded.
The image (taken through cloud!) and spectrum shown below are also in the Gallery.

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   Nova_Tau_2026_image_20260828.jpg
   

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   Nova_Tau_spectrum_20260828_crop-scaled.jpg
   

[Jeremy Shears]

Possible beryllium emission detected in UV: https://www.astronomerstelegram.org/?read=18073

[Mike Harlow]

Thanks for the update Jeremy. Pity they didn’t share the actual spectra
I’m still taking spectra most clear mornings…when they get the forecast right! This morning’s effort attached along with a Zwicky Transient Facility image, A, from July showing nothing at the position of the nova and my image, B, of the same 10 x 10 arc minute field today.
The objective prism spectrum has had some wavelengths (in nanometers) added for reference calculated from the dispersion equation for the system. Interesting that the feature at ~465nm has brightened again at the same phase in the light-curve (from AAVSO) as the previous appearance on 25th August. This followed a flare up of the nova and appeared as it faded. (V-mag ~11.0 today).
The nova has had three mini-outbursts since it first appeared…how many more before it finally fades? And are these like the ‘echo’ outbursts seen in some CV’s, for example EG Cancri?

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   Nova_Tau_2026_20260923.jpg
   

[Gary Poyner]

I think these multiple peaks seen in some novae are caused by shockwaves travelling at different speeds within the ejected material, resulting in seemingly several maxima. Rebrightenings (or echo outbursts) in CV’s are caused by instability in the disc.

Gary

[Mike Harlow]

Just checked the lightcurve of the nova on the AAVSO website…wow! Looks like a DQ Herculis fade is underway. After ~80 days of erratic behaviour it is fading fast…
Mike.

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   NT_lightcurve_20261027.png
   

[Gary Poyner]

ATel #18120 has just been released with details of this sudden drop in magnitude – very probably a ‘dust dip’.

Gary

[Robin Leadbeater]

David Cejudo’s almost daily spectra (calibrated in absolute flux) echo what is described there.
https://britastro.org/specdb/data_graph.php?obs_id=22026%2C22020%2C22010%2C22003%2C21981&multi=yes

Cheers
Robin

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