New supernova SN 2026aaiv in NGC 7331

[Michael Buechner]

On Tuesday, September 1, the ATLAS System discovered the new supernova SN 2026aaiv in NGC 7331 in Pegasus. It is a Type 1a supernova, and at the time of discovery, it had a magnitude of 15.7.

Most people probably remember that a supernova was discovered in NGC 7331 just last year: SN 2025rbs in July 2025.
The new SN found at 22:37:05.618 +34:24:35.37 and is closer to the center

Observation on September 4th
https://britastro.org/observations/observation.php?id=20260906_113344_57bb2dd3c9c77f91

[Robin Leadbeater]

A quick spectrum last night between breaks in the cloud.
https://britastro.org/specdb/data_graph.php?obs_id=21438
Noisy but clearly a type Ia with a good match to several templates using SNID-SAGE at ~ one week pre maximum. (example attached).
The 6355A Si II absorption is at ~6135A giving an explosion velocity of ~ 9500km/s + 900km/s galaxy redshift = ~10500km/s significantly lower than ~13000km/s two nights earlier from spectra in TNS

Cheers
Robin

• This reply was modified 10 hours, 18 minutes ago by Robin Leadbeater. Reason: added TNS link

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   sn2026aaiv_20260905_974_Leadbeater_sn2008Q_Ia-Ia-norm.png
   

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