Carbon Monoxide Production and Excitation in Comet C/1995 O1 (Hale-Bopp): Isolation of Native and Distributed CO Sources

DiSanti, M. A.; Mumma, M. J.; Russo, N. Dello; Magee-Sauer, K.

doi:10.1006/icar.2001.6695

Cited by 147 publications

(166 citation statements)

References 79 publications

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“…Using an extended production for CO consistent with the IR observations does not significantly affect the inferred Q CO . DiSanti et al (2001) inferred a total CO production rate (nuclear+distributed) fully consistent with our value. In the following sections, we assume T = 120 K and a total Q CO of 2 × 10 30 s −1 .…”

Section: On-off Spectrasupporting

confidence: 89%

“…Here, we assumed a Haser parent molecule distribution for CO, and run our excitation model (Sect. 3) with a kinetic temperature T of 120 K which agrees with temperature determinations pertaining to the 10 000-20 000 km (radius) coma region sampled by the primary beam of PdBI (Biver et al 1999a;DiSanti et al 2001). Using an extended production for CO consistent with the IR observations does not significantly affect the inferred Q CO .…”

Section: On-off Spectrasupporting

confidence: 73%

“…CO production rates relative to water are highly variable from comet to comet, ranging from less than 1% to ∼20% (Irvine et al 2000;Bockelée-Morvan et al 2004, for a review). The value obtained in comet Hale-Bopp near perihelion is among the highest ever observed in comets: ∼20% (e.g., Bockelée-Morvan et al 2000;DiSanti et al 2001). 3.…”

Section: Introductionmentioning

confidence: 81%

“…From in situ measurements of the local CO density in 1P/Halley with Giotto, Eberhardt et al (1987) concluded that only about 1/3 of the CO originated in the nucleus. The spatial distribution of CO molecules deduced from infrared long-slit observations of comet Hale-Bopp led DiSanti et al (1999DiSanti et al ( , 2001 to suggest that one-half of the CO was released by a distributed source when comet Hale-Bopp was within 1.5 AU from the Sun. The spatial resolution of the CO maps obtained at PdBI, which corresponded approximately 1000 km to 1700 km radius on the comet depending on the line observed, is below the estimated radial extension of the CO distributed source of ∼5 × 10 3 km (DiSanti et al 2001;Brooke et al 2003).…”

Section: Introductionmentioning

confidence: 99%

“…The spatial distribution of CO molecules deduced from infrared long-slit observations of comet Hale-Bopp led DiSanti et al (1999DiSanti et al ( , 2001 to suggest that one-half of the CO was released by a distributed source when comet Hale-Bopp was within 1.5 AU from the Sun. The spatial resolution of the CO maps obtained at PdBI, which corresponded approximately 1000 km to 1700 km radius on the comet depending on the line observed, is below the estimated radial extension of the CO distributed source of ∼5 × 10 3 km (DiSanti et al 2001;Brooke et al 2003). Therefore, an important aspect of the study of the CO PdBI interferometric data is that independent information about the existence of a CO distributed source in Hale-Bopp coma can possibly be obtained.…”

Section: Introductionmentioning

confidence: 99%

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Interferometric imaging of carbon monoxide in comet C/1995 O1 (Hale-Bopp): evidence of a strong rotating jet

Bockelée‐Morvan¹,

Henry²,

Biver³

et al. 2009

A&A

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Context. Observations of the CO J(1-0) 115 GHz and J(2-1) 230 GHz lines in comet C/1995 O1 (Hale-Bopp) were performed with the IRAM Plateau de Bure interferometer on 11 March, 1997. The observations were conducted in both single-dish (ON-OFF) and interferometric modes with 0.13 km s −1 spectral resolution. Images of CO emission of between 1.7 and 3 angular resolution were obtained. Aims. The ON-OFF and interferometric spectra show a velocity shift with sinusoidal time variations related to the Hale-Bopp nucleus rotation of 11.35 h. The peak position of the CO images moves perpendicularly to the spin axis direction in the plane of the sky. This suggests that a CO jet is present, is active night and day with about the same extent, and is spiralling according to the nucleus rotation. The high quality of the data allows us to constrain the characteristics of this CO jet. Methods. We developed a 3D model to interpret the temporal evolution of CO spectra and maps. The CO coma is represented as the combination of an isotropic distribution and a spiralling gas jet, both of nucleus origin.Results. The analysis of the spectra and visibilities obtained from the interferometric data shows that the CO jet contains ∼40% of the total CO production and is located close to the nucleus equator at a latitude ∼20 • north. Our inability to reproduce all observational characteristics shows that the true structure of the CO coma is more complex than assumed, especially within the first thousand kilometres from the nucleus. The presence of another moving CO structure, faint but compact and possibly created by an outburst, is identified.

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Section: On-off Spectrasupporting

confidence: 89%

Section: On-off Spectrasupporting

confidence: 73%

Section: Introductionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Interferometric imaging of carbon monoxide in comet C/1995 O1 (Hale-Bopp): evidence of a strong rotating jet

Bockelée‐Morvan¹,

Henry²,

Biver³

et al. 2009

A&A

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Water Production and Release in Comet C/1995 O1 Hale–Bopp

Russo

2000

Icarus

102

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Ethane Production and Release in Comet C/1995 O1 Hale–Bopp

Russo

2001

Icarus

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Ethane (C 2 H 6 ) was detected in Comet C/1995 O1 Hale-Bopp on 13 dates between UT 1996 September 20.3 (R h = 3.01 AU preperihelion) and 1997 September 25.7 (R h = 2.83 AU post-perihelion) using high-resolution infrared spectroscopy. Production rates and rotational temperatures were measured, and the derived heliocentric dependence for ethane production was Q = (5.52 ± 0.20) × 10 28 [R (−2.43 ± 0.13) h ] molecules s −1 . The spatial distribution of C 2 H 6 molecules in the coma was consistent with all ethane being released directly from the nucleus, although the possibility that a small fraction was released as a distributed source cannot be excluded. When our derived production rates for ethane, water, and acetylene (C 2 H 2 ) are compared, we obtain an average relative abundance of C 2 H 6 /H 2 O = (6.23 ± 0.42) × 10 −3 , and C 2 H 6 /C 2 H 2 = 2.4 ± 0.7. The high ethane abundance relative to acetylene in Hale-Bopp suggests its ices were altered by radiation processing and/or hydrogenatom addition reactions on the surfaces of ice-mantled grains in the natal cloud. These results are not consistent with ices in Hale-Bopp originating in a thermally or chemically equilibrated region of the solar nebula.

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Carbon Monoxide Production and Excitation in Comet C/1995 O1 (Hale-Bopp): Isolation of Native and Distributed CO Sources

Cited by 147 publications

References 79 publications

Interferometric imaging of carbon monoxide in comet C/1995 O1 (Hale-Bopp): evidence of a strong rotating jet

Interferometric imaging of carbon monoxide in comet C/1995 O1 (Hale-Bopp): evidence of a strong rotating jet

Water Production and Release in Comet C/1995 O1 Hale–Bopp

Ethane Production and Release in Comet C/1995 O1 Hale–Bopp

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