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Thermal model of water and CO activity of Comet C/1995 O1 (Hale-Bopp)

Gortsas, N. and Kührt, E. and Motschmann, U. and Keller, H.U. (2011) Thermal model of water and CO activity of Comet C/1995 O1 (Hale-Bopp). Icarus: International Journal of Solar System Studies, 212 (2), pp. 858-866. Elsevier. DOI: 10.1016/j.icarus.2011.01.017

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Abstract

An investigation of the activity of Comet C/1995 O1 (Hale-Bopp) with a thermophysical nucleus model that does not rely on the existence of amorphous ice is presented. Our approach incorporates recent observations allowing to constrain important parameters that control cometary activity. The model accounts for heat conduction, heat advection, gas diffusion, sublimation, and condensation in a porous iceâ��dust matrix with moving boundaries. Erosion due to surface sublimation of water ice leads to a moving boundary. The movement of the boundary is modeled by applying a temperature remapping technique which allows us to account for the loss in the internal energy of the eroded surface material. These kind of problems are commonly referred to as Stefan problems. The model takes into account the diurnal rotation of the nucleus and seasonal effects due to the strong obliquity of Hale-Bopp as reported by Jorda et al. (Jorda, L., Rembor, K., Lecacheux, J., Colom, P., Colas, F., Frappa, E., Lara, L.M. [1997]. Earth Moon Planets 77, 167â��180). Only bulk sublimation of water and CO ice are considered without further assumptions such as amorphous ices with certain amount of occluded CO gas. Confined and localized activity patterns are investigated following the reports of Lederer and Campins (Lederer, S.M., Campins, H. [2002]. Earth Moon Planets 90, 381â��389) about the chemical heterogeneity of Hale-Bopp and of Bockel�©e-Morvan et al. (Bockel�©e-Morvan, D., Henry, F., Biver, N., Boissier, J., Colom, P., Crovisier, J., Despois, D., Moreno, R., Wink, J. [2009]. Astron. Astrophys. 505, 825â�� 843) about a strong CO source at a latitude of 20. The best fit to the observations of Biver et al. (Biver, N. et al. [2002]. Earth Moon Planets 90, 5â��14) is obtained with a low thermal conductivity of 0.01Wm1 K1. This is in agreement with recent results of the Deep Impact mission to 9P/Tempel 1 (Groussin, O., Aâ��Hearn, M.F., Li, J.-Y., Thomas, P.C., Sunshine, J.M., Lisse, C.M., Meech, K.J., Farnham, T.L., Feaga, L.M., Delamere, W.A. [2007]. Icarus 187, 16â��25) and with previous thermal simulations (K�¼hrt, E. [1999]. Space Sci. Rev. 90, 75â��82). The water production curve matches the production rates well from 4 AU pre-perihelion to the outgoing leg while the model does not reproduce so well the water production beyond 4 AU pre-perihelion. The CO production curve is a good fit to the measurements of Biver et al. (2002) over the whole measured heliocentric range from 7 AU pre- to 15 AU post-perihelion.

Item URL in elib:https://elib.dlr.de/73204/
Document Type:Article
Title:Thermal model of water and CO activity of Comet C/1995 O1 (Hale-Bopp)
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Gortsas, N.nikolaos.gortsas (at) dlr.deUNSPECIFIED
Kührt, E.ekkehard.kuehrt (at) dlr.deUNSPECIFIED
Motschmann, U.uwe.motschmann (at) dlr.deUNSPECIFIED
Keller, H.U.Institute for Geophysics and Extraterrestrial Physics, Technical University of Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, GermanyUNSPECIFIED
Date:14 January 2011
Journal or Publication Title:Icarus: International Journal of Solar System Studies
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:212
DOI :10.1016/j.icarus.2011.01.017
Page Range:pp. 858-866
Publisher:Elsevier
Status:Published
Keywords:Comet Hale-Bopp Comets, Nucleus Comets, Composition Thermal histories Comets, Origin Comets, Coma
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W EW - Erforschung des Weltraums
DLR - Research area:Space
DLR - Program:W EW - Erforschung des Weltraums
DLR - Research theme (Project):W - Projekt ROSETTA Instrumente (old)
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research
Deposited By: Pieth, Susanne
Deposited On:10 Jan 2012 09:09
Last Modified:31 Jul 2019 19:34

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