On a Correlation Between the Radial Velocities of Optical and Radio Interstellar Lines.
Abstract
Optical and 21-cm data pertaining to interstellar clouds are analyzed. The radial velocity correlation coefficient pertaining to the directions toward 39 stars with b > 15 and single component Ca ii lines is +0.68 + 0.09 (m.e.). The dispersion of the histogram of the individual velocity differences is +3 km/sec at both high and low latitudes. A study of the radio and optical line intensities shows an agreement between the theoretical and observed ratios but a discrepancy between the theoretical and observed ,, ratios. Observation and theory can be reconciled by taking the sodium-tohydrogen abundance ratio equal to its value in the sun and by taking the free calcium-to-hydrogen abundance ratio to be of the order of 1/60 of its solar value The possibility of differential calciumhydrogen streaming is briefly discussed.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1963
- DOI:
- 10.1086/147700
- Bibcode:
- 1963ApJ...138..988H