Journal
ASTRONOMY & ASTROPHYSICS
Volume 452, Issue 3, Pages 1039-1048Publisher
EDP SCIENCES S A
DOI: 10.1051/0004-6361:20064925
Keywords
stars : atmospheres; stars : late-type; techniques : spectroscopic; line : formation
Categories
Ask authors/readers for more resources
Aims. We investigate the effect of a geometric inconsistency in the calculation of synthetic spectra of giant stars. Methods. Spectra computed with model atmospheres calculated in spherical geometry while using the plane-parallel approximation for line formation calculations (s_p), as well as the fully plane-parallel case (p_ p), are compared to the consistently spherical case (s_s). Results. We present abundance differences for solar metallicity models with T-eff ranging from 4000 to 6500 K and log g from 0.5 to 3.0 [cgs]. The effects are smaller for s_p calculations (-0.1 dex in the worst case) than for the p_ p case (up to + 0.35 dex for minority species and at most -0.04 dex for majority species), both with respect to the s_s case. In the s_p case the differences increase slightly with temperature, while in the p_ p case they show a more complex behaviour. In both cases the effects decrease with increasing log g and increase with equivalent width. Conclusions. Within the parameter range of F, G and K giants, consistency seems to be less important than using a spherical model atmosphere. The abundance differences due to sphericity effects presented here can be used for error estimation in abundance studies relying on plane-parallel modelling.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available