HD181751 in emission

HD181751 in emission

Postby Andrew Smith » Mon Sep 22, 2014 7:35 am

Hi All I report this observation as much for advice as anything else. I found a B8V star last night that was in emission and not in BeSS.

Data as follows:
HD181751
HIP 95109
RA 19 20 54.3
Dec +22 11 55.6
B 6.47
V 6.55
Sp B8V
BeSS N
2014 09 21
Status e

See attached raw spectra. I am not sure if B8V counts as a classical Be star. This leads to the question of what to do with the B star survey results that turn up suspected Be candidates. I feel we could do with some guidelines to filter the suspects but I am not competent to do this. Any ideas?

Regards Andrew
Attachments
HIP95657.png
HD 181751 HIP 95109 B8V
HIP95657.png (7.13 KiB) Viewed 3293 times
Andrew Smith
 
Posts: 301
Joined: Fri Sep 30, 2011 12:23 pm

Re: HD181751 in emission

Postby Thierry Lemoult » Mon Sep 22, 2014 8:28 am

Congratulation Andrews. I'm not a Be specialist, but i think that should be a new Be according the Jaschek et al. (1981) & Collins (1987) Definition:
"A non-supergiant B star whose spectrum has, or had at some time, one or more Balmer lines in emission"
It's a main sequence star according the "V" in spectral type. I just take a look a CDS bibliography, a found nothing about emission for this star.
I Think Valerie Desnoux can help you. Do not hesitate to contact her.
A high resolution spectrum of this bright star will be usefull. Also, we need a calibrated spectrum: wavelength and a corrected instrumental response.
I will try to obtain a spectrum tonight.

Regards

Thierry Lemoult
Thierry Lemoult
 
Posts: 136
Joined: Thu Sep 29, 2011 9:08 am

Re: HD181751 in emission

Postby Andrew Smith » Mon Sep 22, 2014 11:40 am

Thanks Tierry, I attach a processed image. I have limited the spectral range to that where I feel the instrument response is good. I will try and take confirming spectra tonight as well.
Attachments
HD 181751 HIP 95109.png
Processed Spectra
HD 181751 HIP 95109.png (4.57 KiB) Viewed 3273 times
Andrew Smith
 
Posts: 301
Joined: Fri Sep 30, 2011 12:23 pm

Re: HD181751 in emission

Postby Robin Leadbeater » Mon Sep 22, 2014 7:35 pm

I can confirm the H alpha emission. See attached quick line profile with LHIRES III 2400 tonight.

Robin
Attachments
HD181751_20140922_19-20.png
HD181751_20140922_19-20.png (216.12 KiB) Viewed 3247 times
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
 
Posts: 1263
Joined: Mon Sep 26, 2011 4:41 pm

Re: HD181751 in emission

Postby Andrew Smith » Tue Sep 23, 2014 8:41 am

Firstly thanks Robin for your Hi Res confirmation spectra. I attach a spectra taken 2014 09 22 with the LISA and a 23 micron slit R ~ 1000. Again the images were obtained automatically. HIP 95560 A0V was used to provide the instrument response.

Regards Andrew
Attachments
HIP95109.png
HD 181751 R~1000
HIP95109.png (4.7 KiB) Viewed 3227 times
Andrew Smith
 
Posts: 301
Joined: Fri Sep 30, 2011 12:23 pm

Re: HD181751 in emission

Postby Olivier Thizy » Tue Sep 23, 2014 9:16 am

Just one word: CONGRATULATIONS !!!

Really an excellent work and I believe a first one... I'm sure others will come... :-)

Cordialement,
Olivier Thizy
Vous ne verrez plus des étoiles comme avant !
http://www.shelyak.com/en/
Olivier Thizy
 
Posts: 366
Joined: Sat Sep 24, 2011 10:52 am
Location: in the french Alps...

Re: HD181751 in emission

Postby Andrew Smith » Tue Sep 23, 2014 11:31 am

Thierry Garrel, has pointed out it is included in the photometric HVAR Be catalog so it is not new. We need to develop a screening process. So and advice on where to look would be good.

Regards Andrew
Andrew Smith
 
Posts: 301
Joined: Fri Sep 30, 2011 12:23 pm

Re: HD181751 in emission

Postby Robin Leadbeater » Tue Sep 23, 2014 2:59 pm

Hi Andrew,

The star is indeed mentioned somewhere in the reference Thierry gave
http://cdsbib.u-strasbg.fr/cgi-bin/cdsb ... .125...75P
but if you look in the tables accessible from there
http://vizier.u-strasbg.fr/viz-bin/Vizi ... BAS/125/75
it is listed as a "check star" for the photometry so it is not clear from this if it was actually identified in the paper as a Be star. It would be interesting to read the paper but it is behind a "paywall"

Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
 
Posts: 1263
Joined: Mon Sep 26, 2011 4:41 pm

Re: HD181751 in emission

Postby Robin Leadbeater » Tue Sep 23, 2014 3:08 pm

Checking the abstract again it says

"Altogether, 76 Be stars of all luminosity classes were observed and 13848 UBV measurements secured. Simultaneously, 9648 UBV measurements of 48 check stars (most of them of early spectral types) were obtained."

HD 181751 is definitely listed as a check star so that implies it was not considered a Be star at that time. We would need access to the paper to be sure though.

The statement "76 Be stars of all luminosity classes were observed" in the abstract is confusing too since Be star by definition have to be luminosity class V

Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
 
Posts: 1263
Joined: Mon Sep 26, 2011 4:41 pm

Re: HD181751 in emission

Postby Robin Leadbeater » Tue Sep 23, 2014 3:23 pm

I have now found a copy of the paper
http://aas.aanda.org/articles/aas/pdf/1 ... ds1262.pdf

HD181751 is not in the list of Be stars (table 1), only in the check stars used where there is no mention of emission so it may still be a discovery.

As an aside, the photometry is quite old, going back to 1970's which perhaps predates the definition pf a Be star as a main sequence star so that might explain why all luminosity classes of B star with emission were included in the paper

Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
 
Posts: 1263
Joined: Mon Sep 26, 2011 4:41 pm

Next

Return to Be Search

Who is online

Users browsing this forum: No registered users and 1 guest

cron

x