Suspect Be star HD 194153

[Nico Montigiani]

Guys,
this night during our usual observing session we have recorded 3 spectra of the star HD194153 using the 150 l/mm grating.
In SIMBAD this star is classified as B1Iab.
As you can see in our spectrum here attached there is a faint but well visible H alfa emission.

HD194153_20140916_AAF.JPG (39.22 KiB) Viewed 5060 times

HD194153-HA_20140916_AAF.JPG (45 KiB) Viewed 5060 times

The star is not included in Bess database and we didn't find any literature on internet talking about this star with H alpha emission.

We would like to have your help in order to clarify if this emission in reality is well known or something new.

Hoping in your replies,

Regards

Massimiliano Mannucci
Nico Montigiani

[Olivier Thizy]

Massimiliano,
Nico,


Be stars are B non supergiant stars that display or have displayed emission line in their spectrum. If this star is a B1Iab, this means it is a supergiant.

Those supergiant stars may show emission line but they differ from Be stars. Very good exemples are Deneb, Rigel... Another exemples are Luminous Blue Variables such as P Cygni, eta Carinae...

Emission comes from material expulsed by outflow Wind from those massive & luminous stars.

I hope this helps...


Cordialement,
Olivier Thizy
Vous ne verrez plus des étoiles comme avant !
http://www.shelyak.com/en/

[Nico Montigiani]

Thank you Olivier for your explanation.
Now we understand why the star is not in the BeSS database.
There is another database for this type of stars?

This star was already known as a star emitting?

Regards
Nico Montigiani

[Olivier Thizy]

Nico,


Usually, I start searching on CDS Simbad:
http://simbad.u-strasbg.fr/simbad/sim-fbasic

The spectral type doesn't include an 'e' (B1Iab) which seems to indicate it has not been seen in emission so far.

In CDS, there is also a link to ADS articles - 23 for that star. But a quick bowse of them doesn't seen to indicate an emission either...


Cordialement,
Olivier Thizy
Vous ne verrez plus des étoiles comme avant !
http://www.shelyak.com/en/

[Robin Leadbeater]

I find Brian Skiff's "Opus Magnum" catalogue of MK spectral types useful
http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/mk
It gives the published classifications for a particular star with references
It is an ongoing work with currently 682075 stars
There are 6 references for HD 194153 but no mention of emission

Robin