Comet Hyakutake Spectrum and Tail
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Dust Jets (ESO NTT Image)
Comments by Peter Wehinger (Ariz. State Univ.); 23 February 1996
On reading the caption associated with the latest ESO images of comet Hyakutake ( Photo 14/96 ), obtained in the 6000-7000 A region, I would suggest that the dominant molecular ions would be due to H2O+, especially the (8-0) vibronic band at 6147-6199 A. This band was detected in P/Halley in mid-October 1985 when Halley was at R = 2.2-2.15 AU, by several observers (S. Wyckoff at the MMT 4.5-m, B. A. Peterson at the AAT 3.9-m, and E M Burbidge on the Lick 3-m).
The spectrum acquired at ESO on 09 Feb 1996 ( Photo 12/96 ) is undoubted reduced to show the neutral coma, with strong CN, C3, C2, [OI] 6300 and 6364 A, plus relatively strong NH2 (8-0) and (10-0) bands. We will of course be most interested to see further reductions of these spectra and related observations.