In situ gas and ion measurements at comet Halley

Krankowsky, D.; Lämmerzahl, P.; Herrwerth, I.; Woweries, J.; Eberhardt, P.; Dolder, U.; Herrmann, U.; Schulte, W.; Berthelier, J. J.; Illiano, J. M.; Hodges, R. R.; Hoffman, J. H.

doi:10.1038/321326a0

Cited by 396 publications

(118 citation statements)

References 2 publications

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“…with ISO, S WAS and FIRST) will easily detect the fundamental rotational lines of water. Water was, of course, observed by the Giotto NMS (Krankowsky et al 1986). It was found to constitute 80 % (by number) of the whole cometary gas, thus confirming its status of dominant cometary volatile.…”

Section: Watermentioning

confidence: 82%

“…Unique information was obtained, during the Giotto fly-by of P/Halley, by the Neutral Mass Spectrometer (NMS; Krankowsky et al 1986), the Ion Mass Spectrometer (IMS; Balsiger et al 1986) and the PICCA instrument (Mitchell et al 1992). These data are not easy to interpret.…”

Section: The Methods and Their Reliabilitymentioning

confidence: 99%

“…Carbon dioxide, which cannot be observed from the ground due to the absence of allowed rotational lines and to strong telluric absorption of its IR bands, was strongly suspected from the existence of C02 + . CO2 was observed only in P/Halley through its strong band at 4.3 μπι by VEGA-1 (Combes et al 1988) and through mass spectroscopy by NM S (Krankowsky et al 1986). In the UV spectrum of comet P/Hartley 2 1991 XV observed with the HST, Weaver et al (1994) identified bands of the CO Cameron system around 200 nm that they attributed to CO prompt emission following photodissociation of CO2.…”

Section: Carbon Monoxide and Carbon Dioxidementioning

confidence: 98%

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Molecular Abundances in Comets

Crovisier

1994

Symp. - Int. Astron. Union

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Abstract. The molecular composition of cometary volatiles is a basic information on the nature of comets and a clue to their formation mechanisms. It is only recently that direct identifications of cometary volatiles were obtained through in situ exploration as well as from remote sensing at UV, IR and radio wavelengths. An inventory of known cometary volatiles is presented, with a critical review of the evaluations of their abundances.

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Section: Watermentioning

confidence: 82%

Section: The Methods and Their Reliabilitymentioning

confidence: 99%

Section: Carbon Monoxide and Carbon Dioxidementioning

confidence: 98%

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Molecular Abundances in Comets

Crovisier

1994

Symp. - Int. Astron. Union

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“…The sulfur 34/32 ratio for the gas component in the atmosphere of Comet Halley, obtained from the neutral mass spectrometer (NMS) carried by the Giotto spacecraft, was reported as being identical to the terrestrial ratio, within ± 25% (Krankowsky et al (1986)). However, the large variety of molecular species detected by this experiment makes such a finding uncertain.…”

Section: Other Heavy Elementsmentioning

confidence: 93%

Isotopic Ratios in Comets

Vanysek

1991

International Astronomical Union Colloquium

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ABSTRACT. The isotopic abundances depend on the universal evolution of elements and on the individual history of particular objects. Since it is believed that unprocessed material of the solar nebula is preserved in comets, the data concerning the abundance of stable isotopes in these primitive bodies are of some importance in the cosmological context. The present status of this problem is reviewed. The reliability of results for nuclear species with cosmological and cosmogonical implications, such as D/H, C 12/13, N 14/15, O 16/18, and Mg 24/25/26, is discussed. Significant variation is found for the isotopic abundance of carbon, depending upon which carbon reservoir is sampled. Deuterium is probably enhanced relative to the interstellar ratio. For other isotopes, the ratios are close to those of the terrestrial data. The tendency of the D/H ratio to be at higher values indicates a low temperature in the environment of the comet's formation, and, together with similar effects in the outer planets, suggests that there were two different primordial reservoirs of deuterium in the solar system. The 12 C/ 13 C ratio inferred from in situ mass spectrometry of the dust, as well as from the ground-based optical spectra of the Swan band, tends to be approximately equal to the average terrestrial ratio (89) or larger. Recent results obtained from the CN band provide a significantly lower value (about 65), which corresponds to the carbon isotopic ratio in the diffuse interstellar clouds. The enhancement of deuterium and the possible differences of the carbon isotopic ratio in different species and refractory material are indicative of chemical fractionation processes in the protosolar nebula.

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“…In the case of Chiron, however, it is clear that water cannot be the driving force, since water sublimation becomes very weak beyond -4 AU and is effectively zero at R = 12 AU. A more likely culprit might be CO or C0 2 , the next most abundant volatiles in comet Halley (Kranskowsky et al 1986). Another clue may be revealed in the detection of CN during the outburst of 1990 Jan 29 .…”

Section: Lightcurvesmentioning

confidence: 99%

Cometary activity in distant comets - Chiron

Luu

1993

PASP

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ABSTRACT. Activity in distant comets is one of the most poorly understood topics of cometary studies, but fortunately we now know of a few bright, active distant comets that serve as ideal case studies. Perhaps the best example of these comets is the object 2060 Chiron, a very large comet which started showing signs of activity as distant from the Sun as R -13 AU. Here we summarize recent results on Chiron, culled from our ongoing program to monitor this unusual object. Photometric data gathered in the period 1989-1992 showed that Chiron was capable of short, steep brightening trends (outbursts) in addition to the already known long-term outbursts. The coma is optically thin and gradually dilutes light scattered from the nucleus as the coma grows in strength. The coma also possesses variable surface-brightness profiles which change according to the level of nuclear activity. The outbursts and the variable surface-brightness profiles appear to be common characteristics of active distant comets.

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In situ gas and ion measurements at comet Halley

Cited by 396 publications

References 2 publications

Molecular Abundances in Comets

Molecular Abundances in Comets

Isotopic Ratios in Comets

Cometary activity in distant comets - Chiron

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