A Quantitative Analysis of the Atmospheres of Three Peculiar Low-Luminosity B Stars

Citation

Stewart, John Charles (1955) A Quantitative Analysis of the Atmospheres of Three Peculiar Low-Luminosity B Stars. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/DWVS-1E46. https://resolver.caltech.edu/CaltechETD:etd-02022004-095522

Abstract

NOTE: Text or symbols not renderable in Plain ACII are indicated by [...]. Abstract is included in .pdf document. High-dispersion spectra of HD 37058, HD 37129 and HD 135485, three B stars exhibiting spectral peculiarities, have been studied on the basis of model atmospheres, with a view to detecting abundance anomalies. An approximate theory of high-temperature model atmospheres, applicable to stars in the range of spectral type B 1 - B7 and luminosity classes IV and V, has been developed and applied to the prediction of Balmer line profiles and total intensities of other lines. Temperatures, surface gravities and helium abundances of the three peculiar stars and two standard B stars, [...] Peg and [...] Scl, have been determined. The abundances of other elements have been found from curves of growth using theoretical line strengths. The values of surface gravity derived imply luminosities lower than those of the standard stars. The helium abundance derived for HD 135485 is remarkably large; a sizable titanium excess and an oxygen deficiency were detected in HD 37058.

Thesis Files