Issue |
A&A
Volume 693, January 2025
|
|
---|---|---|
Article Number | A123 | |
Number of page(s) | 13 | |
Section | Planets, planetary systems, and small bodies | |
DOI | https://doi.org/10.1051/0004-6361/202452109 | |
Published online | 10 January 2025 |
Modeling of comet water production
I. Sensitivity to macro- and micro-model parameters
1
Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences,
Nanjing,
PR China
2
School of Astronomy and Space Science, University of Science and Technology of China,
Hefei
230026,
PR China
3
Max-Planck-Institut für Sonnensystemforschung,
Justus-von-Liebig-Weg 3,
37077
Göttingen,
Germany
4
Institut für Geophysik und extraterrestrische Physik, Technische Universität Braunschweig,
Mendelssohnstr. 3,
38106
Braunschweig,
Germany
5
European Space Agency (ESA), ESAC,
Camino Bajo del Castillo s/n,
28692
Villanueva de la Cañada, Madrid,
Spain
★ Corresponding authors; skorov@mps.mpg.de; zhaoyuhui@pmo.ac.cn
Received:
4
September
2024
Accepted:
19
November
2024
Aims. This study investigates the impact of microscopic and macroscopic cometary surface properties on water production variations with heliocentric distance, focusing on dust layer thickness, grain size, nucleus shape, and spin axis orientation.
Methods. We employed a two-layer thermophysical model to calculate effective gas production, incorporating a dust layer of porous aggregates of submillimeter- and millimeter-sized grains. The model includes radiative thermal conductivity and permeability for volatile diffusion and considers dust layer evolution and tensile strength. We examined different cometary nucleus shape models based on spacecraft observations and calculated power-law exponents for water production rates as functions of heliocentric distance.
Results. A two-layer outgassing model with fixed layer properties showed minimal qualitative differences from a simpler water ice sublimation model. The study reaffirms the critical role of the spin axis inclination and illuminated cross-section variation with the heliocentric distance in gas production. Using 67P/Churyumov-Gerasimenko’s orbital parameters, the study demonstrates that dust accumulation and layer growth significantly alter production rate exponents. Additionally, considering tensile strength in a homogeneous spherical nucleus model revealed the potential for local dust crust removal near perihelion.
Conclusions. Macroscopic properties such as nucleus shape and spin axis orientation significantly influence water production rate variations with heliocentric distance. Microscopic surface characteristics and dust layer growth also play crucial roles in cometary activity. Incorporating tensile strength and dust removal mechanisms into models provides a more accurate representation of comet activity, particularly near perihelion. This refined model enhances our understanding of comet outgassing, highlighting the importance of detailed surface property data for an accurate interpretation of observations.
Key words: methods: numerical / comets: general / comets: individual: 67P/Churyumov-Gerasimenko
© The Authors 2025
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.