GAIA transient GAIA21dxg / TNS AT2021wui

[Hamish Barker]

I normalised all to continuum and made a stacked plot around Hbeta. I can't see a trend there, whereas there may be one at Halpha.

at2021wui(normcont)_stacked_Hbeta.png (83.54 KiB) Viewed 11697 times

at2021wui(normcont)_stacked_Halpha.png (85.91 KiB) Viewed 11697 times

[Terry Bohlsen]

I took another spectra of this star. The Ha seems to be dancing around a bit. Maybe just being double peaked and oscillating. Should this star be added to BeSS or somewhere else to keep the spectra we have taken in a central place?
Cheers
Terry

at2021wui(normcont)_20210923_463_TBohlsenHa.png (51.44 KiB) Viewed 11675 times

[Robin Leadbeater]

Should this star be added to BeSS or somewhere else to keep the spectra we have taken in a central place?

BeSS wont include it unless it is confirmed as a classic Be or Herbig AeBe star but you could upload them to the BAA database though for safe keeping
https://britastro.org/specdb/

Robin

[Hamish Barker]

stacked plot of Ha region with all the spectra taken to date by Terry, Peter and myself.

the two sharp peaks of red and blue shifted Ha are about 23 days apart. It will be interesting to see if the sharp peak reapears with blue shift, perhaps 23 days after its peak red shift, around 13 october.

I don't know what the absorbtion is around 5780. I see a dip in B start spectra there, but haven't look up what it is likely to be (or if it could be atmospheric oxygen?).

at2021wui_20210825_to-20210924_Halpha-drift.png (71.67 KiB) Viewed 11620 times

[Terry Bohlsen]

This star has continued to become brighter but is very low in the west now.
I took a spectrum last night when it was only about 14deg above the horizon. As a result the continuum is not properly corrected as I don't have a suitable comparison star at that low altitude. Despite this it seems that the star is no longer in Ha emission. It won't really be possible to take any more spectra of it until the next season.
Terry