Observations of water in comets with Odin

Lecacheux, A.; Biver, Nicolás; Crovisier, J.; Bockelée‐Morvan, Dominique; Baron, Philippe; Booth, R. S.; Encrenaz, P.; Florén, Hans-Gustav; Frisk, U.; Hjalmarson, Å.; Kwok, Sun; Mattila, K.; Nordh, L.; Olberg, M.; Olofsson, A. O. H.; Rickman, H.; Sandqvist, Aa.; Schéele, F. von; Serra, G.; Torchinsky, S.; Volk, Kevin; Winnberg, A.

doi:10.1051/0004-6361:20030338

Cited by 72 publications

(75 citation statements)

References 9 publications

(9 reference statements)

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“…5). Nevertheless, there is a systematic offset by a factor of 2.5 between Combi et al (2011) data and the other measurements (Bockelée-Morvan et al 2004;Fink 2009;Lecacheux et al 2003;Schleicher et al 2003). This was also viewed on the comets Hale-Bopp (Combi et al 2000) and Hyakutake (Combi et al 2005) data.…”

Section: Discussion Of Resultsmentioning

confidence: 64%

CONGO, model of cometary non-gravitational forces combining astrometric and production rate data

Maquet

Colas

Jordá

et al. 2012

A&A

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The gravitational orbit of a comet is affected by the sublimation of water molecules by the nucleus when the comet approaches perihelion. This outgassing triggers a non-gravitational force (NGF) that significantly modifies the orbit of the comet. Up to now, modelling of this effect is mostly based on an empirical model defined in the early 70s that uses a simplified outgassing model. Attempts have been made to use advanced anisotropic thermal models both to calculate the NGF taking several observational constraints into account and to retrieve the nucleus's mass and density, but (i) this approach is restricted to a handful of cometary nuclei that are sufficiently well known to allow this type of modelling, and (ii) the authors usually do not fit the astrometric measurements directly but rather non-gravitational parameters calculated with the above-mentioned empirical model. We present a new model for non-gravitational forces with the aim of revisiting the problem of NGF calculation and nucleus density determination. Our model is closer to the nucleus outgassing physics with only a few free parameters. The amplitude of the perturbation depends on several parameters describing the comet activity that can be constrained by visible, infrared, and radio observations of the coma and the nucleus of the comet. It also depends on the nucleus mass, which can in turn be determined by modelling the effect of the NGF on the orbit of a comet. The method is based on the decomposition of the surface of the nucleus in several elements located at different latitudes. The contribution of each surface element to the overall NGF is fitted from the astrometric measurements, together with the density of the nucleus. This method is the only one available so far to estimate the density of cometary nuclei from ground-based observations. This method is tested on the well-known comet 19P/Borrelly. The density found for these comet is between 150 and 600 kg m −3 .

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Section: Discussion Of Resultsmentioning

confidence: 64%

CONGO, model of cometary non-gravitational forces combining astrometric and production rate data

Maquet

Colas

Jordá

et al. 2012

A&A

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“…Its observation in comets has been a major observing topic for Odin. Previous observations of this line in comets have been reported in Neufeld et al (2000), Lecacheux et al (2003), and Biver et al (2007a).…”

Section: Introductionmentioning

confidence: 62%

Periodic variation in the water production of comet C/2001 Q4 (NEAT) observed with the Odin satellite

Biver¹,

Bockelée‐Morvan²,

Colom³

et al. 2009

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Context. Comet C/2001 Q4 (NEAT) was extensively studied with the 1.1-m submillimetre telescope of the Odin satellite. The H 2 O line at 557 GHz was regularly observed from 6 March to 16 May 2004 and nearly continuously monitored during 3 periods between 26 April and 2 May 2004. Aims. This last set of data shows periodic variations in the line intensity, and we looked for characterising the long-and short-term behaviour of this comet. Methods. We used the variance ratio method and χ 2 minimization to find the period of variation in the water production rate and simulations to infer its amplitude at the nucleus surface. Results. A 40% periodic variation in the water production rate is measured with a period of 0.816 ± 0.004 day (19.58 ± 0.1 h). The comet also exhibits a seasonal effect with a mean peak of outgassing around 2.7 × 10 29 molec. s −1 taking place about 18 days before perihelion.

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“…Several studies of the 1 10 → 1 01 transition observed in other comets suggest a lower electron density (N. Biver, priv. comm., based on data presented by Lecacheux et al (2003), and ). In the absence of mapping observations and multi-line observations of water rotational transitions that can be used to constrain the electron density, the uncertainty in the electron density limits the accuracy of the water production rate that can be derived from submillimeter observations.…”

Section: Radiative Transfer Modelmentioning

confidence: 99%

Submillimeter Wave Astronomy Satellite observations of Comet 9P/Tempel 1 and Deep Impact

Bensch

Melnick

Neufeld

et al. 2007

Icarus

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Observations of water in comets with Odin

Abstract: Abstract. The Odin satellite, which can observe the 1 10 -1 01 rotational line at 557 GHz of ortho water with a high spectral resolution (80 m s −1 ) and a spatial resolution of 2

Cited by 72 publications

References 9 publications

CONGO, model of cometary non-gravitational forces combining astrometric and production rate data

CONGO, model of cometary non-gravitational forces combining astrometric and production rate data

Periodic variation in the water production of comet C/2001 Q4 (NEAT) observed with the Odin satellite

Submillimeter Wave Astronomy Satellite observations of Comet 9P/Tempel 1 and Deep Impact

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