To Be or not to Be (sorry)
Posted: Fri Oct 03, 2014 12:57 pm
Following a valid challenge from Thierry Garrel I outline some criteria that would allow the identification of classical Be stars from the more general categories of B stars showing emission.
This is based on my reading of the paper "Classical Be stars" by Thomas Rivinius et al Astron Astrophys Rev (2013) 21:69.
I am no expert and this is given as a starter for 10 and I invite corrections and comment.
Criteria to Be.
1) Shows Balmer line(s) in emission (or has done in the past).
2) Non super-giant star.
3) High resolution spectra of Balmer lines does not show P Cygni or inverse P Cygni profiles.
4) High resolution spectra do not show forbiden emission lines
5) Does not show a strong infrared excess.
6) Does not have a Roche lobe filling companion.
7) Does not have variability in which the circumstellar environment shows variability with strictly the same period as the photosphere.
It seems to me that criteria 1 to 4 can be tested by amaturs using our spectroscopes and or literature searches.
While criteria 5-7 may be available to literature searches I am not sure about direct observation by us? Builds on this would be welcome.
Regards Andrew
This is based on my reading of the paper "Classical Be stars" by Thomas Rivinius et al Astron Astrophys Rev (2013) 21:69.
I am no expert and this is given as a starter for 10 and I invite corrections and comment.
Criteria to Be.
1) Shows Balmer line(s) in emission (or has done in the past).
2) Non super-giant star.
3) High resolution spectra of Balmer lines does not show P Cygni or inverse P Cygni profiles.
4) High resolution spectra do not show forbiden emission lines
5) Does not show a strong infrared excess.
6) Does not have a Roche lobe filling companion.
7) Does not have variability in which the circumstellar environment shows variability with strictly the same period as the photosphere.
It seems to me that criteria 1 to 4 can be tested by amaturs using our spectroscopes and or literature searches.
While criteria 5-7 may be available to literature searches I am not sure about direct observation by us? Builds on this would be welcome.
Regards Andrew