Detection of Parent Molecules in Comet p/ Halley from the IKS VEGA Experiment
Abstract
Several parent molecules have been detected in comet P/Halley using the 2.5 - 5 μm channel of the IKS experiment aboard Vega 1. The spectral resolving power was about 40 at 2.5 μm and 70 at 5 μm. The ν3 band of H2O has been observed at 2.7 μm, with an intensity corresponding to a production rate of about 1030s-1. The ν3 Band of CO2 has been detected for the first time at 4.3 μm; the derived CO2/H2O ratio is 2×10-2. In addition, there are emission features between 3.3 μm and 3.7 μm, also observed for the first time in a comet, which are attributed to CH-bearing molecules. Their mixing ratio relative to H2O is on the order of a few percent. The ν1 band of H2CO might be present at 3.6 μm, but this interpretation is tentative. A weaker feature also appears at 2.8 μm; it could be tentatively identified as the OH (1-0) band. The CO/H2O ratio is lower than 0.2.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 1987
- Bibcode:
- 1987A&A...187..513M