A Study of Deutero-Ammonia in the Pre-Stellar Condensation in L1689N
Session 84 -- Star Forming Clouds
Display presentation, Wednesday, 11, 1995, 9:20am - 6:30pm

## [84.08] A Study of Deutero-Ammonia in the Pre-Stellar Condensation in L1689N

A. Wootten (NRAO), J. G. Mangum (SMTO)

We present OVRO Millimeter Wave Array, NRAO 12m, and MWO 4.9m measurements of the $1_{11} \rightarrow 1_{01}$ transition of ortho-NH$_2$D toward the L1689N molecular cloud. These measurements indicate that the L1689N core contains at least two solar masses of material at a temperature near 8 K. The oblong structure of the NH$_2$D emission, several thousand AU in extent, lies roughly parallel to the ammonia disk enveloping IRAS16293-2422, about 16000 AU to the east. Any dust core embedded within the molecular core contains less than a few percent of the total molecular mass. From scales of one to ten thousand AU, the temperature and column density of NH$_2$D appear to remain constant. The extent of deuterium fractionation in NH$_3$ suggests that the core temperature has varied little, at least over the past several thousand years.