Stellar atmospheric "turbulence" and stellar kinematics.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Stellar atmospheric "turbulence" and stellar kinematics. Thomas, R. N. Abstract Earlier, the likelihood of stellar atmospheric kinetic temperatures that exceed the radiation temperature has been suggested by the author. Here, the situation in regard to the cause and consequences of such high kinetic temperatures in the solar chromosphere is considered first, as an illustration. The observed chromospheric kinetic temperature of 35,0000, from the work of Wildt and Redman, is adopted. Considering mechanical energy transport as the immediate cause of the kinetic temperature, as earlier suggested, the spicule system found by Roberts is discussed as a possible mechanism in which the velocities are superthermic. Next, the consequences of such a kinetic temperature are considered and found to require appreciable deviation from thermodynamic equilibrium, with 99 per cent of the hydrogen ionized. The heretofore anomalous observations of the behavior of chromospheric helium no longer seem anomalous on this basis. The results of these investigations indicate a pseudo-kinematic effect in radial velocity measures for stars in which the effect is more pronounced than in the sun, if the jet system be the cause, and an anomalous spectroscopic behavior. Attention is called to just such anomalies in the Wolf-Rayet stars, and their harmonious interpretation on the basis of the suggested model. In particular, the simultaneous presence of many stages of ionization for the same element may be laid to departure from thermodynamic equilibrium rather than to stratification. A kinetic temperature of 106 0K is indicated by these spectroscopic results. An independent confirmation of this temperature value is found from an analysis of the density gradient in the WolfRayet star V444 Cygni, presented by Mrs. Shapley and Kopal, for kinetic temperature. Harvard College Observatory, Cambridge, Mass. Publication: The Astronomical Journal Pub Date: June 1948 DOI: 10.1086/106101 Bibcode: 1948AJ.....53..206T full text sources ADS |