gaia22bxd possible new Be Star?

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Hamish Barker
Posts: 226
Joined: Thu Jun 20, 2019 12:11 am

gaia22bxd possible new Be Star?

Post 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
Robin Leadbeater
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Re: gaia22bxd possible new Be Star?

Post 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
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
Posts: 1926
Joined: Mon Sep 26, 2011 4:41 pm
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Re: gaia22bxd possible new Be Star?

Post 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
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Hamish Barker
Posts: 226
Joined: Thu Jun 20, 2019 12:11 am

Re: gaia22bxd possible new Be Star?

Post 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.
Robin Leadbeater
Posts: 1926
Joined: Mon Sep 26, 2011 4:41 pm
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Re: gaia22bxd possible new Be Star?

Post 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
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Terry Bohlsen
Posts: 191
Joined: Thu Sep 29, 2011 7:40 am

Re: gaia22bxd possible new Be Star?

Post 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
Terry Bohlsen
Armidale NSW
Australia
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