Astronomy and Astrophysics – Astrophysics
Scientific paper
Sep 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011ap%26ss.335..113j&link_type=abstract
Astrophysics and Space Science, Vol. 335, No. 1, p. 113-120
Astronomy and Astrophysics
Astrophysics
Line: Profiles, Stars: Fundamental Parameters, Stars: Supergiants, Techniques: Spectroscopic, Ultraviolet: Stars
Scientific paper
We determined atmospheric parameters of the Galactic early B-supergiant HD 198478 (55 Cyg) from the UV silicon lines taken from the high-resolution 1150-1980 Å IUE spectra. TLUSTY numerical code was used to model the stellar atmosphere and to determine the temperature and surface gravity assuming a non-LTE plane parallel hydrostatic stellar atmosphere with microturbulence. The synthesized spectra were broadened by the IUE instrumental profile, rotational and macroturbulent velocity with ROTIN numerical code. The silicon 1264 Å, 1309 Å, 1312 Å, 1417 Å and 1294-1303 Å multiplet lines of different stages of ionization (Si II and Si III) and Balmer Hδ 4101 Å line were modeled, leading to the temperature, surface gravity, rotational and macroturbulent velocity values. Our results have shown that the line broadening cannot be explained by rotational velocity only, but additional macroturbulent velocity component should be taken into account. HD 198478 shows a significant degeneracy in velocity, which means that the individual contributions of the macroturbulence and rotation in the total velocity broadening cannot be distinguished. Adequate fit of TLUSTY models to the observed non-resonant silicon lines suggests that the non-LTE plane-parallel hydrostatic stellar model without wind contribution can be used to explain such lines. We have obtained similar results using the HST STIS spectra in the same procedure, showing that the IUE spectra, despite their lacking quality compared to the STIS spectra, are reliable enough in determination of the B supergiants' photospheric parameters.
Dominis Prester Dijana
Jurkic Tomislav
Kotnik-Karuza Dubravka
Sarta Deković Mariza
No associations
LandOfFree
Atmospheric parameters of the B-supergiant HD 198478 from the UV spectra 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 Atmospheric parameters of the B-supergiant HD 198478 from the UV spectra, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Atmospheric parameters of the B-supergiant HD 198478 from the UV spectra will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1079554