Contributions Toward a Physical Model of γ Cassiopeiae

Abstract

view Abstract Citations (9) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Contributions Toward a Physical Model of γ Cassiopeiae Baldwin, Ralph B. Abstract The light-curve and the temperature-curve of -y Cassiopeiae are correlated in a peculiar manner. An explanation is that the photosphere of the star is variable in size and that a reduced color temperature depends on an increase in the extent of the ra- diating surface relative to the available energy. The law of conservation of angular momentum may be used to explain these corre- lations. The broad absorption lines are observed to change in width; and if this is interpreted as a change in the velocity of rotation, we immediately have relative radii of the star for all dates covered by measures of the absorption width. The original absolute magnitude and the light-curve permit computation of a temperature-curve, which is found to be in agreement with the observed temperature-curve. This principle allows a determination of the radii of the layers of emission. It is found that the atmosphere is stratified and that it pulsates in a manner similar to the photo- sphere but with a moderate lag. Equivalent widths of certain sharp absorption lines of helium and hydrogen have been measured, and the method of Struve and Wurm has been applied to give the distance from the photosphere to the "shell" in which the lines were produced. The results are consistent with the radii determined from the broad absorption and emission lines; the sharp absorption lines are produced in the outermost layers. Variations in the emission intensity ratios of the two components of the lines of ten elements are shown to exist and are discussed Publication: The Astrophysical Journal Pub Date: July 1940 DOI: 10.1086/144203 Bibcode: 1940ApJ....92...82B full text sources ADS |