Nova Sco2024c

Peter Velez · Post by **Peter Velez** » Sun Sep 15, 2024 7:46 am

Some spectra on the latest nova in Scorpio. BY way of background, the nova was originally discovered on 2024-09-09.4363 UT at 11.4 mag (unfiltered) (see CBAT notification here:http://www.cbat.eps.harvard.edu/unconf/ ... 28079.html ). It was classified as a classical nova by Yusuke Tampo later that day (see ATel 16808 here:https://www.astronomerstelegram.org/?read=16808 ).

I have collected spectra on the nova on 10, 13 and 14 September. Some of you may recall that I have my UVEX grating tuned to roughly match the Johnson-Cousins photometric system. Below are plots for each of the B, V and Ic ranges. I've included Ic data to get a glimpse of the O I triplet in the near IR.

All spectra were taken with a UVEX using a 600 lines/mm grating mounted on a Planewave CDK12.5 telescope operated from Siding Spring Observatory in NSW, Australia. Exposures comprise 3 x 1200s processed with SpecInti.

I ran into an odd situation with the V and B data on 10 September. I used HD150742 as my reference star, thinking that a B3V star would give me good signal in the UV. For some reason, the continuum of the V spectra seems flat while the B spectrum declines more rapidly in the blue and UV. I haven't included it in the plots below for this reason but have included it separately as there are nice P Cygni profiles evident. I'm open to any suggestions as to the cause of this disconnect. There was only 30 minutes or so between the V and B spectra were taken so I don't think there is anything intrinsic to the nova changing - once again, I am certain its pilot error.

This nova seems to be moving along at quite a rate - I find the OI triplet in the Ic spectra particularly interesting. I need to go back and rewatch Steve Shore's recent presentation now!

(Note: for some odd reason the forum reports that I've reached the quota for adding attachments. I'll post the successive B spectra and the faintly suspicious looking V spectrum separately).

Pete