CH- ja OH- molekyylien pylvästiheyksien välinen korrelaatio tähtienvälisessä molekyylipilvessä TMC-1

Abstract

The correlation between the column densities of two common interstellar molecules, CH and OH, was examined in the interstellar molecular cloud TMC-1. The research was performed by measuring the Λ-doubling spectral line of CH at several points along a filament in TMC-1 and comparing the result with previously reduced OH measurements of the same area. A strong correlation (RCH,OH ≈ 0.92) was noticed between CH and OH in such a way that N(OH) ∼ (8.3±0.5) ·N(CH). The observa- tions in TMC-1 passed over a cyanopolyyne peak where previous research has found long carbon chain compounds such as HC7N. A strong CH maximum was observed in the same location as this cyanopolyyne peak. This indicates that the region around the cyanopolyyne peak contains plentiful free coal in either C- or C+- forms. These are required for the formation of both CH and cyanopolyynes. A significant shift in the velocities of the CH spectral lines was noticed in addition to the CH maximum in the region around the cyanopolyyne peak. This shift and the CH maximum are both in an area which was identified in 1992 by Hirahara et al. as core “D” and we believe that the velocity shift indicates the border of this core. Because there seems to be a high abundance of free coal in the “D” core as indicated by the CH measurements, it seems to represent an early phase in the chemical evolution of a molecular cloud.