Mass and Energy Balance in the Near-Surface Layers of a Cometary Nucleus

Skorov, Yu. V.; Kömle, Norbert I.; Markiewicz, W. J.; Keller, H. U.

doi:10.1006/icar.1999.6134

Cited by 39 publications

(30 citation statements)

References 27 publications

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“…It rapidly decreases when the thickness increases, in agreement with the work of Julian et al (1999) on comet 1P/Halley. This analysis does not take into account the advection of the gas in the crust which allows to transport more energy from the top of the crust to its bottom through the pores, inducing a higher temperature under the crust than the one we calculated and therefore a higher water production rate (Skorov et al 1999). Consequently, the thickness of the crust required to inhibit the water production could be larger, and the time to form it longer.…”

Section: Influence Of a Refractory Crust On The Water Production Ratementioning

confidence: 87%

Activity on the surface of the nucleus of comet 46P/Wirtanen

Groussin

Lamy

2003

A&A

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Abstract. We present a thermal model of the nucleus of comet 46P/Wirtanen, constrained by the temporal variations of the water production rate, in order to understand the activity on its surface. We consider a spherical nucleus with a macroscopic mosaic of small and numerous active and inactive regions. At heliocentric distances r h > 1.5 AU, the active regions represent 5-15% of the surface. At ∼1.5 AU, a rapid increase takes place and the active fraction reaches 70 to 100% in about 10 days, and then remains approximately constant up to perihelion where Q H 2 O = 1.3 ± 0.3 × 10 28 molecule s −1 . Post-perihelion, this fraction returns to ∼10%. The model is consistent with a geometric albedo ≤0.06. A refractory crust likely forms post-perihelion and can explain the variations of the activity over an orbit. Finally, we derived an erosion of ∼0.5 m per revolution and a remaining lifetime for the nucleus of several hundred revolutions.

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Section: Influence Of a Refractory Crust On The Water Production Ratementioning

confidence: 87%

Activity on the surface of the nucleus of comet 46P/Wirtanen

Groussin

Lamy

2003

A&A

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“…The low thermal inertia of Chiron indicates a low thermal conductivity for the surface material, and probably a porous surface as supposed for the majority of cometary nuclei (e.g. Klinger et al 1996;Skorov et al 1999).…”

Section: Thermal Inertia and Radius Determination Of The Nucleusmentioning

confidence: 88%

Properties of the nuclei of Centaurs Chiron and Chariklo

Groussin

Lamy

Jordá

2004

A&A

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Abstract. We analyze visible, infrared, radio and spectroscopic observations of 2060 Chiron in a synthetic way to determine the physical properties of its nucleus. From visible observations performed from 1969 to 2001, we determine an absolute V magnitude for the nucleus of 7.28 ± 0.08 with an amplitude of 0.16 ± 0.03, implying a nearly spherical nucleus with a ratio of semi-axes a/b = 1.16 ± 0.03. Infrared observations at 25, 60, 100 and 160 µm (i.e., covering the broad maximum of the spectral energy distribution) obtained with the Infrared Space Observatory Photometer (ISOPHOT) in June 1996 when Chiron was near its perihelion are analyzed with a thermal model which considers an intimate mixture of water ice and refractory materials and includes heat conduction into the interior of the nucleus. We find a very low thermal inertia of 3and a radius of 71 ± 5 km. Combining the visible and infrared observations, we derive a geometric albedo of 0.11 ± 0.02. We find that the observed spectra of Chiron can be fitted by a mixture of water ice (∼30%) and refractory (∼70%) grains, and that this surface model has a geometric albedo consistent with the above value. We also analyze the visible, infrared and radio observations of Chariklo (1997 CU26) and derive a radius of 118 ± 6 km, a geometric albedo of 0.07 ± 0.01 and a thermal inertia of 0A mixture of water ice (∼20%) and refractory (∼80%) grains is compatible with the near-infrared spectrum and the above albedo.

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“…We note that the effects of solar radiation pressure on a curved jet are not considerable in our simulation, but will be involved in the future. The equation of motion is (Gombosi et al 1986;Skorov et al 1999;Molina et al 2008)…”

Section: Numerical Simulationmentioning

confidence: 99%

Observations and analysis of a curved jet in the coma of comet 67P/Churyumov-Gerasimenko

Lin

Lai

et al. 2016

A&A

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Aims. We analyze the physical properties and dynamical origin of a curved jet of comet 67P/Churyumov-Gerasimenko that was observed repeatedly in several nucleus rotations starting on May 30 and persisting until early August, 2015. Methods. We simulated the motion of dust grains ejected from the nucleus surface under the influence of the gravity and viscous drag effect of the expanding gas flow from the rotating nucleus. Results. The formation of the curved jet is a combination of the size of the dust particles (∼0.1−1 mm) and the location of the source region near the nucleus equator. This enhances the spiral feature of the collimated dust stream after the dust is accelerated to a terminal speed on the order of m s −1 .

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Mass and Energy Balance in the Near-Surface Layers of a Cometary Nucleus

Cited by 39 publications

References 27 publications

Activity on the surface of the nucleus of comet 46P/Wirtanen

Activity on the surface of the nucleus of comet 46P/Wirtanen

Properties of the nuclei of Centaurs Chiron and Chariklo

Observations and analysis of a curved jet in the coma of comet 67P/Churyumov-Gerasimenko

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