The Dust-to-Gas Ratio, Size Distribution, and Dust Fall-Back Fraction of Comet 67P/Churyumov-Gerasimenko: Inferences From Linking the Optical and Dynamical Properties of the Inner Comae

Marschall, Raphael; Markkanen, Johannes; Gerig, Selina-Barbara; Pinzón-Rodríguez, O.; Thomas, N.; Wu, Jong‐Shinn

doi:10.3389/fphy.2020.00227

Cited by 45 publications

(23 citation statements)

References 46 publications

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“…For H 2 O, we obtained a steeper slope before perihelion than after with α values of -4.2 and -3.6 respectively. The value before perihelion is consistent with previous studies based on measurements analyses (values between -3.8 to -7.0) while our results after perihelion is lower (values between -4.3 to -7.1) (Hansen et al, 2016, Marshall et al, 2017, 2020a, Shinnaka et al, 2017, Läuter et al, 2019. Our slopes match the observations better than the significantly lower slope (about -2.8 for the model A) provided by the thermal model of Keller et al (2015b).…”

Section: Global Production Ratessupporting

confidence: 93%

“…These values are in agreement with results and uncertainties obtained during the Rosetta mission (Fulle et al 2016a, Langevin et al 2016, Merouane et al 2017, Choukroun et al 2020, Marschall et al 2020a) and imply a limited amount of particles greater than 1 cm (Marschall et al 2020a). However, a single power law may not fit properly the data over the whole dust size range and it should be noticed that while large particles are not abundant, they might represent most of the dust mass (Fulle et al 2016).…”

Section: J O U R N a L P R E -P R O O Fsupporting

confidence: 91%

“…The results are scaled with a free parameter referred to as the Effective Active Fraction (EAF) translating the fact that the surface of the comet is not fully active. An EAF of 20% is applied to our volatiles outgassing to match the observed total volatiles loss and maximum production peak (Marschall et al, 2017, 2020a, Läuter et al, 2019, Combi et al, 2020. This value is higher than the typical evaluated value of about 1% used by other groups (Gulkis et al, 2015, Marschall, et al, 2020b, which is a consequence of the subsurface sublimation processes included in the model J o u r n a l P r e -p r o o f Fig.…”

Section: Global Production Ratesmentioning

confidence: 99%

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New constraints on the chemical composition and outgassing of 67P/Churyumov-Gerasimenko

Herny

Mousis

Marschall

et al. 2021

Planetary and Space Science

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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Section: Global Production Ratessupporting

confidence: 93%

Section: J O U R N a L P R E -P R O O Fsupporting

confidence: 91%

Section: Global Production Ratesmentioning

confidence: 99%

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New constraints on the chemical composition and outgassing of 67P/Churyumov-Gerasimenko

Herny

Mousis

Marschall

et al. 2021

Planetary and Space Science

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“…Now the main problem is not the general simulation of the dusty gas flows but rather the derivation of the boundary conditions via fitting of simulations to the available observational data (e.g. Bieler et al 2015a;Fougere et al 2013Fougere et al , 2016bMarschall et al , 2017Zakharov et al 2018a;Combi et al 2020;Marschall et al 2020b). We discuss this link of the nucleus surface (i.e.…”

Section: The Development Of Multidimensional Cometary Gas and Dust Momentioning

confidence: 99%

“…Finally, linking gas and dust models as done e.g. by Marschall et al (2020b) for the entire Rosetta mission fitting ROSINA and OSIRIS data allows for a comprehensive look at the dust and gas mass loss. They found that a power-law of q = 3.7 +0.57 −0.078 for the dust size distribution is consistent with the data and in line with independent measurements previously reported by COSIMA and GIADA .…”

Section: Similarities and Differences Of Models Of 67pmentioning

confidence: 99%

Cometary Comae-Surface Links

et al. 2020

Self Cite

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A comet is a highly dynamic object, undergoing a permanent state of change. These changes have to be carefully classified and considered according to their intrinsic temporal and spatial scales. The Rosetta mission has, through its contiguous in-situ and remote sensing coverage of comet 67P/Churyumov-Gerasimenko (hereafter 67P) over the time span of August 2014 to September 2016, monitored the emergence, culmination, and winding down of the gas and dust comae. This provided an unprecedented data set and has spurred a large effort to connect in-situ and remote sensing measurements to the surface. In this review, we address our current understanding of cometary activity and the challenges involved when linking comae data to the surface. We give the current state of research by describing what we know about the physical processes involved from the surface to a few tens of kilometres above it with respect to the gas and dust emission from cometary nuclei. Further, we describe how complex multidimensional cometary gas and dust models have developed from the Halley encounter of 1986 to today. This includes the study of inhomogeneous outgassing and determination of the gas and dust production rates. Additionally, the different approaches used and results obtained to link coma data to the surface will be discussed. We discuss forward and inversion models and we describe the limitations of the respective approaches. The current literature suggests that there does not seem to be a single uniform process behind cometary activity. Rather, activity seems to be the consequence of a variety of erosion processes, including the sublimation of both water ice and more volatile material, but possibly also more exotic processes such as fracture and cliff erosion under thermal and mechanical stress, sub-surface heat storage, and a complex interplay of these processes. Seasons and the nucleus shape are key factors for the distribution and temporal evolution of activity and imply that the heliocentric evolution of activity can be highly individual for every comet, and generalisations can be misleading.

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Comet Interceptor Mission

Jones

Snodgrass

Tubiana

et al. 2021

Encyclopedia of Astrobiology

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Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA's F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum ΔV capability of 600 ms −1 . Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes -B1, provided by the Japanese space agency, JAXA, and B2 -that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission's science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule.

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The Dust-to-Gas Ratio, Size Distribution, and Dust Fall-Back Fraction of Comet 67P/Churyumov-Gerasimenko: Inferences From Linking the Optical and Dynamical Properties of the Inner Comae

Cited by 45 publications

References 46 publications

New constraints on the chemical composition and outgassing of 67P/Churyumov-Gerasimenko

New constraints on the chemical composition and outgassing of 67P/Churyumov-Gerasimenko

Cometary Comae-Surface Links

Comet Interceptor Mission

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