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Observation by Kevin Gurney: Supernova spectrum

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Kevin Gurney


Kevin Gurney


2021 Apr 15 - 00:30


2021 Apr 15 - 15:55

  • Celestron C11
  • Alpy600
  • Atik 460EX
  • Focal reducer 0.63x

18 x 300s



Target name

SN 2021hiz


Supernova spectrum

About this image

I saw the alert for this on the CV email list. It seemd just within my grasp at around V13, and it was a clear night...

It is a Type Ia which is well documented spectroscopically in Richard Walker's Spectroscopy Atlas. It was gratifying to see that I could identify features such as the 'silcon valley', blueshifted from around 6360 due to the expanding  wavefront (towards us, as we see it). This is indicative of a velocity of around 9500km/s! There is also the 'W-absorption' of SII at around 5400. I estimated the V-magnitude (using an 80mm refractor) at 12.97.

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Robin Leadbeater
Robin Leadbeater, 2021 Apr 19 - 12:47 UTC

Hi Kevin,

Don't forget to include the redshift of the host galaxy when estimating the expansion velocity. In this case the redshift is 0.0033  so the Si II rest wavelength of 6360 is shifted to 6381 making the measured velocity ~1000km/s higher



Kevin Gurney
Kevin Gurney, 2021 Apr 20 - 17:42 UTC

Hi Robin,

Good point!




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