On the CO and N2 abundance in Comet HalleyThe mass 28 amu/e signal observed in the neutral mode of the Giotto neutral gas mass spectrometer (NMS) is evaluated. At 1000 km from the nucleus number density n(CO)/ n(H2O) is less than or = 0.07. The production rate of CO as a parent molecule directly from the nucleus is thus less than 7% of the H2O production rate. However, CO is also produced from an extended source in the inner coma (r is less than 20,000 km) and at 20,000 km from the nucleus, for the total equivalent CO production rate 0.05 is less than or = Q(CO)/Q(H2O) is less than or = 0.15. For N2 an upper limit Q(N2)/Q(H2O) is less than or = 0.1 is derived. No parent molecule for the CO is identified in agreement with the NMS measurements. It is proposed that CO or a very short-lived parent is released in the coma from cometary dust grains, such as the CHON particles.
Document ID
19870015774
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Eberhardt, P. (Bern Univ. Bern, Switzerland)
Krankowsky, D. (Bern Univ. Bern, Switzerland)
Schulte, W. (Bern Univ. Bern, Switzerland)
Dolder, U. (Bern Univ. Bern, Switzerland)
Laemmerzahl, P. (Bern Univ. Bern, Switzerland)
Berthelier, J. J. (Bern Univ. Bern, Switzerland)
Woweries, J. (Bern Univ. Bern, Switzerland)
Stubbemann, U. (Bern Univ. Bern, Switzerland)
Hodges, R. R. (Bern Univ. Bern, Switzerland)
Hoffmann, J. H. (Centre de Recherches en Physique de l'Environnement Saint Maur des Fosses, France)
Date Acquired
September 5, 2013
Publication Date
December 1, 1986
Publication Information
Publication: ESA Proceedings of the 20th ESLAB Symposium on the Exploration of Halley's Comet. Volume 1: Plasma and Gas