Shock-Induced Behavior of Atomic Species in LPV Atmospheres

Extract

A dynamic model of the LPV atmosphere which calculates the time-dependent variations of density, temperature, velocity, and composition with radius has been used to predict changes in absorption line profiles with phase. General results based on density variations are shown in figure 1. Similar graphs, based on concentrations of individual species, are presented for six metals: Fe, Si, Mg, Ca, Cr, and Ti. Those species which remain essentially proportional to the density (e.g., most neutral metals) exhibit the same type of variation. Ionized metals show more individual variations, including some doubling at certain phases, caused by enhanced ionization in the regions traversed by the upper shock. The basic variation predicted by this model has been observed for CO lines in Chi Cygni. (Hinkle, Hall, and Ridgway 1982, Ap. J. 252, 697)