Transport and Distribution of Hydroxyl Radicals and Oxygen Atoms from H2O Photodissociation in the Inner Coma of Comet 67P/Churyumov–Gerasimenko

Lai, Ian-Lin; Su, C. C.; Ip, W.-H.; Wei, Chen En; Wu, Jingwei; Lo, Ming Chung; Liao, Ying; Thomas, N.

doi:10.1007/s11038-016-9481-6

Cited by 4 publications

(1 citation statement)

References 35 publications

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“…the nucleus radius), we obtain values of Kn \ 0.01 at perihelion for comet C-G and Kn [ 0.1 above low activity areas at higher heliocentric distances such as 3.5 au (see e.g. Lai et al 2015). The rapid decrease in density (*1/R 2 where R is the distance to the nucleus) as the gas expands leads to Kn increasing well into the domain of non-equilibrium flows a few kilometers above the surface.…”

Section: Introductionmentioning

confidence: 72%

3D Direct Simulation Monte Carlo Modelling of the Inner Gas Coma of Comet 67P/Churyumov–Gerasimenko: A Parameter Study

Liao

Marschall

et al. 2016

Earth Moon Planets

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Direct Simulation Monte Carlo (DSMC) is a powerful numerical method to study rarefied gas flows such as cometary comae and has been used by several authors over the past decade to study cometary outflow. However, the investigation of the parameter space in simulations can be time consuming since 3D DSMC is computationally highly intensive. For the target of ESA's Rosetta mission, comet 67P/Churyumov-Gerasimenko, we have identified to what extent modification of several parameters influence the 3D flow and gas temperature fields and have attempted to establish the reliability of inferences about the initial conditions from in situ and remote sensing measurements. A large number of DSMC runs have been completed with varying input parameters. In this work, we present the simulation results and conclude on the sensitivity of solutions to certain inputs. It is found that among cases of water outgassing, the surface production rate distribution is the most influential variable to the flow field.

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Section: Introductionmentioning

confidence: 72%

3D Direct Simulation Monte Carlo Modelling of the Inner Gas Coma of Comet 67P/Churyumov–Gerasimenko: A Parameter Study

Liao

Marschall

et al. 2016

Earth Moon Planets

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Gas outflow and dust transport of comet 67P/Churyumov–Gerasimenko

Lai

et al. 2016

Monthly Notices of the Royal Astronomical Society

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The 3D Direct Simulation Monte Carlo Study of Europa’s Gas Plume

Tseng

Lai

et al. 2022

Universe

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Europa has been spotted as having water outgassing activities by space- and ground-based telescopes as well as reanalysis of the Galileo data. We adopt a 3D Direct Simulation Monte Carlo (DSMC) model to investigate the observed plume characteristics of Europa assuming that supersonic expansion originated from the subsurface vent. With a parametric study of the total gas production rate and initial gas bulk velocity, the gas number density, temperature and velocity information of the outgassing plumes from various case studies were derived. Our results show that the plume gases experience acceleration through mutual collisions and adiabatic cooling when exiting from the surface. The central part of the plume with relatively large gas production rates (1029 and 1030 H2O s−1) was found to sustain thermal equilibrium and near continuum condition. Column density maps integrated along two different viewing angles are presented to demonstrate the importance of the projection effect on remote sensing diagnostics. Finally, the density profiles at different altitudes are provided to prepare for observations of Europa’s plumes including upcoming spacecraft missions such as JUICE and Europa Clipper.

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Transport and Distribution of Hydroxyl Radicals and Oxygen Atoms from H2O Photodissociation in the Inner Coma of Comet 67P/Churyumov–Gerasimenko

Cited by 4 publications

References 35 publications

3D Direct Simulation Monte Carlo Modelling of the Inner Gas Coma of Comet 67P/Churyumov–Gerasimenko: A Parameter Study

3D Direct Simulation Monte Carlo Modelling of the Inner Gas Coma of Comet 67P/Churyumov–Gerasimenko: A Parameter Study

Gas outflow and dust transport of comet 67P/Churyumov–Gerasimenko

The 3D Direct Simulation Monte Carlo Study of Europa’s Gas Plume

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