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AT 2020nvb: possible supernova (13.1 mag) in NGC 4457

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SPK's picture
AT 2020nvb: possible supernova (13.1 mag) in NGC 4457

AT 2020nvb (SN:)

Discovered by Koichi Itagaki:
CCD image at

This transient is confimed by recent ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017PASP..129j4502K) data at
gmag. 13.1 (corrected) on 2020 July 1.260 UT.

Spectroscopy and multiband photometry are required.

Clear skies,

AT 2020nvb Sequence

The sequence for AT 2020nvb is complete and in VSP.

F chart (18.5 arcminute)

Erik Schwendeman

AAVSO Sequence Team


SPK's picture
Type Ia (now in VSX)

Thanks a lot for the comparison star sequence, Erik!
Supernova 2020nvb has been added to the International Variable Star Index:


weo's picture
SN 2020nvb - Alert Notice 709

AAVSO Alert Notice 709 reports on the discovery of the bright Type Ia supernova SN 2020nvb in NGC 4457 (Vir). Please see the notice for details and observing instructions.

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ

CrossoverManiac's picture
Question: isn't the supernova

Question: isn't the supernova really "close" to the galactic core and does that mean SN 2020nvb has to be observed at high magnification to separate it from the galactic core?

Also, is it possible to measure SN 2020 nvb and NGC 4457 together and extrapolate the supernova's brightness from initial brightness of the galaxy?

Deconinck Michel
Deconinck Michel's picture
Indeed quite close
CrossoverManiac's picture
I'm going have to use my

I'm going have to use my ASI183MM to get close to that resolution, though I didn't want to since it's only a 12-bit camera.

SN 2020nvb - Alert Notice 709

Hello! I gave it a try. Difficult target. I don't trust my analysis and deleted my observations. Best regards.


CrossoverManiac's picture
I took a second shot and was

I took a second shot and was able to barely get in one two-minute exposure in V and the other in B before the weather turned bad.  If anyone wants to look, I can send you the images I used.

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