Evidence for distributed gas sources of hydrogen halides in the coma of comet 67P/Churyumov–Gerasimenko

Keyser, Johan De; Dhooghe, Frederik; Altwegg, Kathrin; Balsiger, H.; Berthelier, Jean‐Jacques; Briois, C.; Calmonte, Ursina; Cessateur, Gaël; Combi, M. R.; Equeter, Eddy; Fiethe, Björn; Fuselier, S. A.; Gasc, Sébastien; Gibbons, Andrew; Gombosi, T. I.; Gunell, H.; Hässig, Myrtha; Roy, Léna Le; Maggiolo, Romain; Mall, U.; Marty, Bernard; Neefs, Eddy; Rème, H.; Rubin, Martin; Sémon, Thierry; Tzou, Chia-Yu; Würz, Peter

doi:10.1093/mnras/stx2725

Cited by 31 publications

(13 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This trend is observed with increasing elevation, which would then imply that evaporation of some dark material took place in the inner coma. Evidence for the degradation of grains in the coma of 67P are however still very sparse (e.g., hydrogen halides and glycine are released from dust, De Keyser et al 2017;Altwegg et al 2016). Incidentally, we note that, in presence of rapidly subliming (i.e., small and dirty) ice grains, the trend would have been opposite.…”

Section: Radial Variation Of the Bolometric Albedomentioning

confidence: 65%

VIRTIS-H observations of the dust coma of comet 67P/Churyumov-Gerasimenko: spectral properties and color temperature variability with phase and elevation

Bockelée‐Morvan

Leyrat

Erard

et al. 2019

A&A

View full text Add to dashboard Cite

We analyze 2-5 µm spectroscopic observations of the dust coma of comet 67P/Churyumov-Gerasimenko obtained with the VIRTIS-H instrument onboard Rosetta from 3 June to 29 October 2015 at heliocentric distances r h = 1.24-1.55 AU. The 2-2.5 µm color, bolometric albedo, and color temperature are measured using spectral fitting. Data obtained at α = 90 • solar phase angle show an increase of the bolometric albedo (0.05 to 0.14) with increasing altitude (0.5 to 8 km), accompanied by a possible marginal decrease of the color and color temperature. Possible explanations include the presence in the inner coma of dark particles on ballistic trajectories, and radial changes in particle composition. In the phase angle range 50-120 • , phase reddening is significant (0.031 %/100 nm/ • ), for a mean color of 2 %/100 nm at α = 90 • , that can be related to the roughness of the dust particles. Moreover, a decrease of the color temperature with decreasing phase angle is also observed at a rate of ∼ 0.3 K/ • , consistent with the presence of large porous particles, with low thermal inertia, and showing a significant day-to-night temperature contrast. Comparing data acquired at fixed phase angle (α = 90 • ), a 20% increase of the bolometric albedo is observed near perihelion. Heliocentric variations of the dust color are not significant in the analyzed time period. Measured color temperatures are varying from 260 to 320 K, and follow a r 0.6 h variation in the r h = 1.24-1.5 AU range, close to the expected r 0.5 h value.

show abstract

Section: Radial Variation Of the Bolometric Albedomentioning

confidence: 65%

VIRTIS-H observations of the dust coma of comet 67P/Churyumov-Gerasimenko: spectral properties and color temperature variability with phase and elevation

Bockelée‐Morvan

Leyrat

Erard

et al. 2019

A&A

View full text Add to dashboard Cite

show abstract

“…No such distributed source detection has been reported so far, however. It is interesting to note that De Keyser et al (2017) have also reported a distributed source for HCl and HF due to waterice sublimation from dust particles in the atmosphere of comet 67P. No distributed source of water is detected in their data either, however, because the contribution of sublimating water from the icy dust particles to the total water budget in the coma is suspected to be minor.…”

Section: Discussionmentioning

confidence: 96%

Distributed glycine in comet 67P/Churyumov-Gerasimenko

Hadraoui

Cottin

Ivanovski

et al. 2019

A&A

View full text Add to dashboard Cite

Most of the gaseous molecules that are detected in cometary atmospheres are produced through sublimation of nucleus ices. Distributed sources may also occur, that is, production within the coma, from the solid component of dust particles that are ejected from the nucleus. Glycine, the simplest amino acid, was observed episodically in the atmosphere of comet 67P/Churyumov-Gerasimenko (67P) by the ROSINA mass spectrometer on board the Rosetta probe. A series of measurements on 28 March 2015 revealed a distributed density profile at between 14 and 26 km away from the nucleus. We here present and discuss three study cases: (i) glycine emitted directly and only from the nucleus, (ii) glycine emitted from the sublimation of solid-state glycine on the dust particles that are ejected from the nucleus, and (iii) glycine molecules embedded in water ice that are emitted from the sublimation of this ice from the dust particles that are ejected from the nucleus. A numerical model was developed to calculate the abundance of glycine in the atmosphere of comet 67P as a function of the distance from the nucleus, and to derive its initial abundance in the lifted dust particles. We show that a good fit to the observations corresponds to a distributed source of glycine that is embedded in sublimating water ice from dust particles that are ejected from the nucleus (iii). The few hundred ppb of glycine embedded in water ice on dust particles (nominally 170 ppb by mass) agree well with the observed distribution.

show abstract

“…The escaping material may still contain volatiles which affect the dust-to-gas ratio, see e.g. De Keyser et al (2017) and Altwegg et al (2016). In addition, the dust-to-gas ratio may differ from the dust-to- 4.8 ± 1.5 × 10 9 2.0 6.1 ± 0.3 × 10 2 CO 2 9.5 ± 3.8 × 10 33 7.0 ± 2.8 × 10 8 4.9 8.6 ± 0.4 × 10 CO 3.6 ± 1.1 × 10 33 1.7 ± 0.5 × 10 8 1.7 2.0 ± 0.1 × 10 O 2 2.6 ± 0.8 × 10 33 1.4 ± 0.4 × 10 8 1.8 1.4 ± 0.7 × 10 Table 1.…”

Section: Global Gas Productionmentioning

confidence: 99%

Surface localization of gas sources on comet 67P/Churyumov-Gerasimenko based on DFMS/COPS data

Läuter

Kramer

Rubin

et al. 2018

Monthly Notices of the Royal Astronomical Society

Self Cite

114

View full text Add to dashboard Cite

We reconstruct the temporal evolution of the source distribution for the four major gas species H 2 O, CO 2 , CO, and O 2 on the surface of comet 67P/Churyumov-Gerasimenko during its 2015 apparition. The analysis applies an inverse coma model and fits to data between August 6th 2014 and September 5th 2016 measured with the Double Focusing Mass Spectrometer (DFMS) of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) and the COmet Pressure Sensor (COPS). The spatial distribution of gas sources with their temporal variation allows one to construct surface maps for gas emissions and to evaluate integrated productions rates. For all species peak production rates and integrated productions rates per orbit are evaluated separately for the northern and the southern hemisphere. The nine most active emitting areas on the comet's surface are defined and their correlation to emissions for each of the species is discussed.

show abstract

Evidence for distributed gas sources of hydrogen halides in the coma of comet 67P/Churyumov–Gerasimenko

Cited by 31 publications

References 69 publications

VIRTIS-H observations of the dust coma of comet 67P/Churyumov-Gerasimenko: spectral properties and color temperature variability with phase and elevation

VIRTIS-H observations of the dust coma of comet 67P/Churyumov-Gerasimenko: spectral properties and color temperature variability with phase and elevation

Distributed glycine in comet 67P/Churyumov-Gerasimenko

Surface localization of gas sources on comet 67P/Churyumov-Gerasimenko based on DFMS/COPS data

Contact Info

Product

Resources

About