Some observations of the SI lines in B-type stars.
Abstract
The strengths of the lines S~II X4I30, 81111, X4552, and S~Iv X4089 have been measured on high-dispersion plates for Io B-type stars, and these data have been combined with published values to establish average values. The data are as follows. Siii 3jul Siiv Type Stars 4130 4552 4059 Sources A A A BoV rSco .145 .174 I Bo.5 V E Per .04 .53 .36 2 BI V 21856 .05 .34 .12 2 24131 ~ Peg B2IV ~Cas .035 .152 .032 2,3,4,5 ~ Cet ~ Her B3V 35An .094 .123 .018 2,4,5 B~ IV L Aql r Her .176 .039 2, 3 Bo.5111 i'Aql .04 .51 .13 2 BI II 205139 .03 .39 .16 2 B211 ~CMa .076 .392 .130 3,6 I A. Unsold, Zs. Astroph. 21, 1, 1941. 2 A. B. Underhill, this paper. 3 A. B. Underhill, Ap. J. 107, 349, 1949. 4 L. H. Aller, Ap. J. 109, 244, 1949. 5 L. Neven, Thesis, Liege, 1952. 6 L. H. Aller, Ap. J. 123, 117, 1956. The resulting line ratios have been used to classify the theoretical spectra of 4 B- type model atmospheres. The models with po = 16,8000, log g = 3.80, and P5 = 16,8000, log g = 4.20 correspond to type B2.5 IV-V. The models with P5 = 18,8000, log g = 3.80, and P5 = 18,8000, log g = 4.20 correspond to Bi.5 V. The models are composed of pure H. There is evidence that at BI.5 the strong line X4552 is formed largely in a "chromosphere exterior to the models which are designed to produce the continuous spectrum correctly. Dominion Astrophysical Observatory, Victoria, B. C.
- Publication:
-
The Astronomical Journal
- Pub Date:
- May 1957
- DOI:
- 10.1086/107472
- Bibcode:
- 1957AJ.....62...96U