N+2 and CO+ in Comets 122P/1995 S1 (deVico) and C/1995 O1 (Hale–Bopp)

McDonald Observatory, University of Texas at Austin, Austin, Texas, 78712, .utexas.eduf1
Icarus 03/2000; DOI: 10.1006/icar.2000.6413
Source: arXiv

ABSTRACT We observed Comets 122P/1995 S1 (deVico) and C/1995 O1 (Hale–Bopp) with high spectral resolving power in order to determine the ratio of N+2/CO+ in their comae. While we clearly detected the CO+ in both of these comets, no N+2 was detected in either comet. From these spectra, we derive sensitive upper limits for N+2/CO+. These upper limits are substantially below other reported detections of N+2/CO+ in other comets. We discuss the prior N+2 detections and compare them with our observations. The abundance of N2 in comets is important to our understanding of the condensation of ices in the solar nebula. In addition, N2 is a tracer of Ar so the study of N2 allows an understanding of the role of comets for delivering volatiles to the terrestrial planets. It appears that many, if not most, comets are depleted in N2 and it will be necessary to search for a mechanism for depleting this molecule in order to be consistent with current models of the solar nebula.

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    Dataset: VQ94 I

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