Page 1 of 1

gaia22bxd possible new Be Star?

Posted: Wed Jun 22, 2022 9:17 pm
by Hamish Barker
gaia22bxd (http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia22bxd/ ) also notified as AT2022ksd https://www.wis-tns.org/object/2022ksd

has brightened by about 0.3 magnitudes in the last 6 months, to about magnitude 9.7.

I have taken several spectra, here is an addition of 2 consecutive days. Looks like a B or A type star with a little H alpha emission and maybe there is also some emission in the middle of the Hgamma absorbtion line.

Any suggestions on where to take this or likely classification?
gaia22bxd_20220621-22_528_Hamish Barker.png

Re: gaia22bxd possible new Be Star?

Posted: Wed Jun 22, 2022 10:26 pm
by Robin Leadbeater
It is HD124791 with a classification of B8II.
https://simbad.u-strasbg.fr/simbad/sim- ... D%20124791
If correct it is a giant so not a classical Be, though the classification (from a reference in 1975) could be wrong of course.

(I've found Be candidates in the past and passed them on to Coralie Neiner (also some erroneous entries in the BeSS list of stars) but never heard anything back so I don't know if there is any interest. The current lack of progress in getting BeSS fixed is annoying too)

Cheers
Robin

Re: gaia22bxd possible new Be Star?

Posted: Wed Jun 22, 2022 10:33 pm
by Robin Leadbeater
Follow up at high resolution could be the next step, following the procedure used for the past Be survey
http://www.astrosurf.com/aras/be_candid ... idate.html
http://www.spectro-aras.com/forum/viewforum.php?f=32

Robin

Re: gaia22bxd possible new Be Star?

Posted: Wed Jun 22, 2022 11:25 pm
by Hamish Barker
Thanks robin, I was going to email you directly. Can send the fits files if interested. I have a couple of additional observations as I was not happy with whether the spectra roughness is intrinsic, or just low s/n.

Re: gaia22bxd possible new Be Star?

Posted: Thu Jun 23, 2022 12:19 pm
by Robin Leadbeater
Hi Hamish,

Since it is not a previously known emission line star it is probably worth at least classifying it as "other" on TNS with zero redshift ? With a description of the spectrum along the lines of

"spectrum shows a blue continuum with Balmer lines in absorption and H alpha with a central emission component. The redshift is close to zero indicating a galactic source, possibly a Be star"

Cheers
Robin

Re: gaia22bxd possible new Be Star?

Posted: Sat Jun 25, 2022 1:38 am
by Terry Bohlsen
I have also taken a spectra of this star. It is also known as HD124791 and is catalogued as a B8II C on SIMBAD. It certainly seems to be a B star and it has some weak He lines. I can only identify H emission at Ha.
Terry
hd124791_20220624_490_TBohlsen.png