Spectrum synthesis of sharp-lined A and B stars

Details Spectrum synthesis of sharp-lined A and B stars Spectrum synthesis of sharp-lined A and B stars

1998-05-14

arxiv.org/abs/astro-ph/9805191v1

Astronomy and Astrophysics

Astrophysics

3 pages, 1 figure, to appear in: Proc. of the 26th workshop of the European Working Group on CP stars, eds. P. North, A. Schne

Scientific paper

I have carried out spectrum synthesis of R = 120,000 spectra of several A and B stars having v sin i less than about 6 km/s. The following conclusions emerge: (1) As T_e descends from 12,000 to 8,000 K, microturbulent velocity xi deduced from abundance analysis rises steadily from 0 to about 5 km/s. (2) Stars with xi >= 1 km/s show direct evidence in their line profiles of the presence of macroscopic gas motions in the form of line asymmetry (bisector curvature) which grows with increasing xi. (3) Above T_e ~ 9000 K, both weak and strong spectral lines can be modelled with reasonable accuracy by conventional LTE spectrum synthesis with a single assumed model atmosphere, abundance table, v sin i, and an appropriate (constant) value of xi. (4) In contrast, at T_e ~ 8,000 K the weak spectral lines are much narrower than the strong lines. If the synthesis model is constrained in v sin i and xi by the weak lines, NO satisfactory model can be found for the strong spectral lines. Consequently, chemical abundances for such stars based only on strong lines may be significantly in error.

Affiliated with

Also associated with

No associations

Rating

Spectrum synthesis of sharp-lined A and B stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Spectrum synthesis of sharp-lined A and B stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spectrum synthesis of sharp-lined A and B stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-667703