Spectrum of Comet C/2023 A3

[David Boyd]

This spectrum was taken last night, 17th October, at a mean altitude of 20 deg as the comet approached the western horizon.

The strong variation in intensity along the lower spectral image of the comet is largely due to the combined wavelength sensitivity profile of the spectroscope (LISA) and camera (SXVR-H694). This is corrected for in the comet spectrum above, along with wavelength-dependent atmospheric losses, using the spectrum of a B9 star recorded immediately after the comet at a similar altitude. The spectroscope list was across the comet nucleus and the spectra were guided on the nucleus.

Apart from strong emission of CN at 3883 A, the spectrum lacks other strong emission lines from CN, C2 and NH2 which I have seen in spectra of other comets.

David

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   C2023-A3.png
   

[Robin Leadbeater]

Hi David,

What was the orientation of the slit relative to the comet? The sodium emission line is seen only on one side of the coma so presumably is from the sodium tail rather than any light pollution/atmospheric emission line

Cheers
Robin

[Robin Leadbeater]

The weakness of the Swan band emission does confirm earlier observations that it is a carbon depleted comet eg
https://www.astronomerstelegram.org/?read=16637

Cheers
Robin

• This reply was modified 1 month, 3 weeks ago by Robin Leadbeater.

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