Composition-dependent outgassing of comet 67P/Churyumov-Gerasimenko from ROSINA/DFMS

Luspay‐Kuti, A.; Hässig, Myrtha; Fuselier, S. A.; Mandt, K.; Altwegg, Kathrin; Balsiger, H.; Gasc, Sébastien; Jäckel, A.; Roy, Léna Le; Rubin, Martin; Tzou, Chia-Yu; Würz, Peter; Mousis, O.; Dhooghe, Frederik; Berthelier, Jean‐Jacques; Fiethe, Björn; Gombosi, T. I.; Mall, U.

doi:10.1051/0004-6361/201526205

Cited by 73 publications

(79 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This distribution follows the general observations with a dominant source of H 2 O released from the Hapi region of the nucleus following the nomenclature from Thomas et al (2015), while more CO 2 is produced in the southern hemisphere of the nucleus notably with the principal source south of the Imhotep region and above the Khonsu region. These results are consistent with the observations made by the different instruments on board Rosetta (Biver et al 2015;Gulkis et al 2015;Hässig et al 2015;Bockelée-Morvan et al 2015;Lee et al 2015;Luspay-Kuti et al 2015;Migliorini et al 2016). Calculations by Keller et al (2015) show that the total energy input close to the Hapi region is enhanced by reflected light and IR radiation from the walls of the local concavity, which could explain the H 2 O distribution of activity.…”

Section: Description Of the Activity At The Surface Of The Nucleussupporting

confidence: 92%

“…Finally, the sums of the relative abundances of the four major coma species (H 2 O, CO 2 , CO, and O 2 ) are constrained such that added up they fit the total gas density measured by COPS. We focus solely on H 2 O and CO 2 since the density evolution of most minor species is correlated to either one or the other of these two species (Luspay-Kuti et al 2015 This approach is performed from 4 August 2014 up to 2 June 2015, a few days after equinox. Figure 2 shows the DFMS measured densities for the two species of interest for this study: H 2 O and CO 2 .…”

Section: Data Analysis and Derivationmentioning

confidence: 99%

See 1 more Smart Citation

Three-dimensional direct simulation Monte-Carlo modeling of the coma of comet 67P/Churyumov-Gerasimenko observed by the VIRTIS and ROSINA instruments on board Rosetta

Fougere

Altwegg

Berthelier

et al. 2016

A&A

Self Cite

100

View full text Add to dashboard Cite

Context. Since its rendezvous with comet 67P/Churyumov-Gerasimenko (67P), the Rosetta spacecraft has provided invaluable information contributing to our understanding of the cometary environment. On board, the VIRTIS and ROSINA instruments can both measure gas parameters in the rarefied cometary atmosphere, the so-called coma, and provide complementary results with remote sensing and in situ measurement techniques, respectively. The data from both ROSINA and VIRTIS instruments suggest that the source regions of H 2 O and CO 2 are not uniformly distributed over the surface of the nucleus even after accounting for the changing solar illumination of the irregularly shaped rotating nucleus. The source regions of H 2 O and CO 2 are also relatively different from one another. Aims. The use of a combination of a formal numerical data inversion method with a fully kinetic coma model is a way to correlate and interpret the information provided by these two instruments to fully understand the volatile environment and activity of comet 67P. Methods. In this work, the nonuniformity of the outgassing activity at the surface of the nucleus is described by spherical harmonics and constrained by ROSINA-DFMS data. This activity distribution is coupled with the local illumination to describe the inner boundary conditions of a 3D direct simulation Monte-Carlo (DSMC) approach using the Adaptive Mesh Particle Simulator (AMPS) code applied to the H 2 O and CO 2 coma of comet 67P. Results. We obtain activity distribution of H 2 O and CO 2 showing a dominant source of H 2 O in the Hapi region, while more CO 2 is produced in the southern hemisphere. The resulting model outputs are analyzed and compared with VIRTIS-M/-H and ROSINA-DFMS measurements, showing much better agreement between model and data than a simpler model assuming a uniform surface activity. The evolution of the H 2 O and CO 2 production rates with heliocentric distance are derived accurately from the coma model showing agreement between the observations from the different instruments and ground-based observations. Conclusions. We derive the activity distributions for H 2 O and CO 2 at the surface of the nucleus described in spherical harmonics, which we couple to the local solar illumination to constitute the boundary conditions of our coma model. The model presented reproduces the coma observations made by the ROSINA and VIRTIS instruments on board the Rosetta spacecraft showing our understanding of the physics of 67P's coma. This model can be used for further data analyses, such as dust modeling, in a future work.

show abstract

Section: Description Of the Activity At The Surface Of The Nucleussupporting

confidence: 92%

Section: Data Analysis and Derivationmentioning

confidence: 99%

Three-dimensional direct simulation Monte-Carlo modeling of the coma of comet 67P/Churyumov-Gerasimenko observed by the VIRTIS and ROSINA instruments on board Rosetta

Fougere

Altwegg

Berthelier

et al. 2016

A&A

Self Cite

100

View full text Add to dashboard Cite

show abstract

“…The composition of the coma is complex and rich, including numerous additional species, such as organics. However, their volume mixing ratios relative to water are less than a few per cent, often significantly less (Goesmann et al 2015;Le Roy et al 2015;Luspay-Kuti et al 2015;Wright et al 2015;Altwegg et al 2016). O 2 , which was detected for the first time on a cometary coma by ROSINA-DFMS, is the fourth most abundant species at comet 67P (Bieler et al 2015a).…”

Section: Neutral Composition From Rosinamentioning

confidence: 99%

Ionospheric plasma of comet 67P probed byRosettaat 3 au from the Sun

Galand

Héritier

Odelstad

et al. 2016

Mon. Not. R. Astron. Soc.

Self Cite

170

View full text Add to dashboard Cite

We propose to identify the main sources of ionization of the plasma in the coma of comet 67P/Churyumov-Gerasimenko at different locations in the coma and to quantify their relative importance, for the first time, for close cometocentric distances (<20 km) and large heliocentric distances (>3 au). The ionospheric model proposed is used as an organizing element of a multi-instrument data set from the Rosetta Plasma Consortium (RPC) plasma and particle sensors, from the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis and from the Microwave Instrument on the Rosetta Orbiter, all on board the ESA/Rosetta spacecraft. The calculated ionospheric density driven by Rosetta observations is compared to the RPC-Langmuir Probe and RPC-Mutual Impedance Probe electron density. The main cometary plasma sources identified are photoionization of solar extreme ultraviolet (EUV) radiation and energetic electron-impact ionization. Over the northern, summer hemisphere, the solar EUV radiation is found to drive the electron density -with occasional periods when energetic electrons are also significant. Over the southern, winter hemisphere, photoionization alone cannot explain the observed electron density, which reaches sometimes higher values than over the summer hemisphere; electron-impact ionization has to be taken into account. The bulk of the electron population is warm with temperature of the order of 7-10 eV. For increased neutral densities, we show evidence of partial energy degradation of the hot electron energy tail and cooling of the full electron population.

show abstract

“…Later H 2 O, CO 2 , and CO were detected by the ROSINA mass spectrometer Hässig et al 2015). The most recent measurements also indicate a significant spatial/temporal variability of the relative abundances of volatiles in the coma (Luspay-Kuti et al 2015). Nevertheless, the relative abundance of CO/CO 2 , CO 2 /H 2 O, and CO/H 2 O are not fully consistent among the different instruments (Morse et al 2015).…”

Section: Introductionmentioning

confidence: 99%

A model of short-lived outbursts on the 67P from fractured terrains

Skorov

Rezac

Hartogh

et al. 2016

A&A

View full text Add to dashboard Cite

Aims. We develop a physical model to explain the potent outbursts that occurred in the fractured terrain of comet 67P near perihelion, and predict its temporal characteristics. Methods. The feasibility of the proposed mechanism is studied using a numerical model accounting for the relevant microscopic/macroscopic processes. We rely on the thermophysical, compositional, and geo-morphological data from the published measurements of respective instruments on board Rosetta. Results. The key idea of this novel mechanism is built around observations of fractures/cracks in the region of interest. It is argued that as the stresses on the nucleus increased during the perihelion approach, a crack deepening event occurred reaching the deeper material containing super-volatile ices in equilibrium with the surrounding. This sudden opening lead to a violent sublimation of the super-volatile ices. The time scales and mass release of this process are modeled and reported. In our modeling we pay attention to the question of the existence of super-volatile ices in the deeper interior for a long time, and the thermal equilibrium in the interior. Conclusions. The deepening of pre-existing cracks (fracture) into the material containing highly volatile ices can explain the observed outburst features. The sudden disequilibration of the steady-state reservoir of highly volatile ices results in a violent release of gas and dust. The proposed mechanism also explains the rapid shut down of this activity in accordance with the observations. The proposed mechanism is independent of solar illumination history of a given region, or the pre-existance of large sealed nucleus cavities.

show abstract

Composition-dependent outgassing of comet 67P/Churyumov-Gerasimenko from ROSINA/DFMS

Cited by 73 publications

References 21 publications

Three-dimensional direct simulation Monte-Carlo modeling of the coma of comet 67P/Churyumov-Gerasimenko observed by the VIRTIS and ROSINA instruments on board Rosetta

Three-dimensional direct simulation Monte-Carlo modeling of the coma of comet 67P/Churyumov-Gerasimenko observed by the VIRTIS and ROSINA instruments on board Rosetta

Ionospheric plasma of comet 67P probed byRosettaat 3 au from the Sun

A model of short-lived outbursts on the 67P from fractured terrains

Contact Info

Product

Resources

About