Detection of Interstellar H 3O +: A Confirming Line
Abstract
Observations are reported from a line coincident in frequency with the (J, K) = (3, 2)-(2, 2) 364.797427 GHz transition which is argued to arise from H3O(+). Two lines of this ion lie at frequencies accessible to earth-bound telescopes, and both were detected. Mapping shows that the emission extends over about 1 pc in Sgr B2 but lies concentrated to the core (about 0.07 pc in OMC-1. The source of the emission is identified as H3O(+), and it is found that the abundance X(H3O/+/) is approximately equal to 1 x 10 exp -9 - 5 x 10 exp -9. It is concluded that the abundance of H3O(+) is in reasonable agreement with chemical models, and that the H2O/H3O(+) ratio lies at the low end of the range of predictions of chemical models. It is inferred that the size of the emission regions are limited by the size of regions where substantial release of water from grain surfaces has occurred.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 1991
- DOI:
- 10.1086/186178
- Bibcode:
- 1991ApJ...380L..79W
- Keywords:
-
- Emission Spectra;
- Hydronium Ions;
- Interstellar Chemistry;
- Interstellar Matter;
- Abundance;
- Astronomical Spectroscopy;
- Cosmic Dust;
- Electron Transitions;
- Astrophysics;
- ABUNDANCES;
- INTERSTELLAR: ABUNDANCES