The MG II H and K Interstellar Lines in the Spectrum of the G-Type Giant HD 156854
Kondo, Y.; Shore, Steven N.; Gurzadian, G. A.; Terzian, Yervant; Cholakian, V. G.
Armenia, United States
Abstract
The results of the measurements and analysis of the IUE observations of the 2800 Mg II doublet in the spectrum of HD 156854, a G9 III star, are presented. The relative power of the magnesium chromosphere, R(Mg) = 0.00001, is in agreement with the known data for giants of the same class. The emission profiles of this doublet present absorption cores, which are of interstellar origin. Taking into account the interstellar depletion of Mg, the derived density of interstellar hydrogen is n(H) = 0.001/cu cm, which agrees with the conclusion (Paresce 1984) about the possibility of large hydrogen concentrations in some directions of the Galaxy far from the sun.