scholarly journals The gas production of 14 species from comet 67P/Churyumov–Gerasimenko based on DFMS/COPS data from 2014 to 2016

2020 ◽  
Vol 498 (3) ◽  
pp. 3995-4004 ◽  
Author(s):  
Matthias Läuter ◽  
Tobias Kramer ◽  
Martin Rubin ◽  
Kathrin Altwegg
Keyword(s):  
Error Bounds ◽  
Temporal Evolution ◽  
Gas Production ◽  
Total Production ◽  
Time Intervals ◽  
Triangular Elements ◽  
Double Focusing ◽  
Comet 67P ◽  
Northern And Southern Hemispheres

ABSTRACT The coma of comet 67P/Churyumov–Gerasimenko has been probed by the Rosetta spacecraft and shows a variety of different molecules. The ROSINA COmet Pressure Sensor and the Double Focusing Mass Spectrometer provide in situ densities for many volatile compounds including the 14 gas species H2O, CO2, CO, H2S, O2, C2H6, CH3OH, H2CO, CH4, NH3, HCN, C2H5OH, OCS, and CS2. We fit the observed densities during the entire comet mission between 2014 August and 2016 September to an inverse coma model. We retrieve surface emissions on a cometary shape with 3996 triangular elements for 50 separated time intervals. For each gas, we derive systematic error bounds and report the temporal evolution of the production, peak production, and the time-integrated total production. We discuss the production for the two lobes of the nucleus and for the Northern and Southern hemispheres. Moreover, we provide a comparison of the gas production with the seasonal illumination.

scholarly journals A comparison between the two lobes of comet 67P/Churyumov–Gerasimenko based on D/H ratios in H2O measured with the Rosetta/ROSINA DFMS

2019 ◽  
Vol 489 (4) ◽  
pp. 4734-4740 ◽  
Author(s):  
Isaac R H G Schroeder ◽  
Kathrin Altwegg ◽  
Hans Balsiger ◽  
Jean-Jacques Berthelier ◽  
Michael R Combi ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
European Space Agency ◽  
Cometary Nucleus ◽  
The Other ◽  
Appreciable Difference ◽  
Space Agency ◽  
Close Proximity ◽  
Double Focusing ◽  
Comet 67P

ABSTRACT The nucleus of the Jupiter-family comet 67P/Churyumov–Gerasimenko was discovered to be bi-lobate in shape when the European Space Agency spacecraft Rosetta first approached it in 2014 July. The bi-lobate structure of the cometary nucleus has led to much discussion regarding the possible manner of its formation and on how the composition of each lobe might compare with that of the other. During its two-year-long mission from 2014 to 2016, Rosetta remained in close proximity to 67P/Churyumov–Gerasimenko, studying its coma and nucleus in situ. Based on lobe-specific measurements of HDO and H2O performed with the ROSINA Double Focusing Mass Spectrometer (DFMS) on board Rosetta, the deuterium-to-hydrogen (D/H) ratios in water from the two lobes can be compared. No appreciable difference was observed, suggesting that both lobes formed in the same region and are homogeneous in their D/H ratios.

scholarly journals 16O/18O ratio in water in the coma of comet 67P/Churyumov-Gerasimenko measured with the Rosetta/ROSINA double-focusing mass spectrometer

2019 ◽  
Vol 630 ◽  
pp. A29 ◽  
Author(s):  
Isaac R. H. G. Schroeder I ◽  
Kathrin Altwegg ◽  
Hans Balsiger ◽  
Jean-Jacques Berthelier ◽  
Johan De Keyser ◽  
...  
Keyword(s):  
Solar System ◽  
Mass Spectrometer ◽  
European Space Agency ◽  
Space Agency ◽  
Close Proximity ◽  
Terrestrial Water ◽  
Double Focusing ◽  
Comet 67P ◽  
Almost Continuous

The European Space Agency spacecraft Rosetta accompanied the Jupiter-family comet 67P/Churyumov-Gerasimenko for over 2 yr along its trajectory through the inner solar system. Between 2014 and 2016, it performed almost continuous in situ measurements of the comet’s gaseous atmosphere in close proximity to its nucleus. In this study, the 16O/18O ratio of H2O in the coma of 67P/Churyumov-Gerasimenko, as measured by the ROSINA DFMS mass spectrometer onboard Rosetta, was determined from the ratio of H216O/H218O and 16OH/18OH. The value of 445 ± 35 represents an ~11% enrichment of 18O compared with the terrestrial ratio of 498.7 ± 0.1. This cometary value is consistent with the comet containing primordial water, in accordance with leading self-shielding models. These models predict primordial water to be between 5 and 20% enriched in heavier oxygen isotopes compared to terrestrial water.

Analyzing 67P’s dusty coma

2021 ◽  
Author(s):  
Nora Hänni ◽  
Kathrin Altwegg ◽  
Daniel Müller ◽  
Boris Pestoni ◽  
Martin Rubin ◽  
...  
Keyword(s):  
Data Sets ◽  
Volatile Species ◽  
Complex Species ◽  
Time Period ◽  
Starting Point ◽  
Double Focusing ◽  
Dust Grain ◽  
Comet 67P ◽  
Unique Capability

<p>While the volatile species in comet 67P/Churyumov-Gerasimenko’s coma have been analyzed in great spatial and temporal detail, e.g., Rubin et al. (2019) or Läuter et al. (2020), little is so far known about the less volatile, heavier species. There is growing evidence, however, that less volatile species, such as salts, may play a key role in explaining some of the puzzling properties of comets, as for instance shown by Altwegg et al. (2020). These authors also have demonstrated the unique capability of ROSINA/DFMS (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis/ Double Focusing Mass Spectrometer; Balsiger et al. (2007)) to detect exactly such little volatile species in-situ, namely during a dust event on 5 September 2016 (when a dust grain entered the instrument and sublimated inside).</p><p>Complementary information on 67P’s dusty coma can be obtained from data collected during time periods of high dust activity. A clear advantage of such data is they also allow for a quantitative interpretation thanks to the much more stable measurement conditions. Moreover, a comparison to data collected during a time period of little dust activity (e.g., to the days around end of May 2015 as in Rubin et al. 2019) also allows to link species to dust.</p><p>End of July / beginning of August 2015, the comet was approaching its perihelion and ejecting a lot of dust, as seen by the OSIRIS camera (Vincent et al. 2016). The data from this period are therefore a promising starting point for the search of heavier species (m > 100 Da). Altwegg et al. (2019), for instance, reported on the tentative identifications of the simplest polyaromatic hydrocarbon species naphthalene as well as of benzoic acid, the simplest aromatic carboxylic acid. To confirm these identifications and to achieve a more complete inventory of heavier and chemically more complex species, we are now analyzing these data sets strategically. In our contribution we will share what we have learned from pushing the exploration of 67P’s dusty coma.</p><p> </p><p>Altwegg et al., 2020, Nat. Astron., 4, 533-540.<br>Altwegg et al., 2019, Annu. Rev. Astron. Astrophys., 57, 113-55.<br>Balsiger H. et al., 2007, Space Sci. Rev., 128, 745-801.<br>Läuter et al., 2020, MNRAS, 498, 3, 3995-4004.<br>Rubin et al., 2019, MNRAS, 489, 594-607. Vincent et al., 2016, MNRAS, 462 (Suppl_1), 184-194.</p>

In-situ detection of cometary cyanogen (NCCN)

2020 ◽  
Author(s):  
Nora Hänni ◽  
Kathrin Altwegg ◽  
Boris Pestoni ◽  
Martin Rubin ◽  
Isaac Schroeder ◽  
...  
Keyword(s):  
Production Rate ◽  
Hydrogen Cyanide ◽  
Space Science ◽  
Upper Limit ◽  
Rosetta Mission ◽  
Long Time ◽  
Double Focusing ◽  
In Situ Detection ◽  
Comet 67P

<p>For a long time it was thought that the cyano (CN) radical, observed remotely many times in various stellar and interstellar environments, is exclusively a photodissociation product of hydrogen cyanide (HCN). Bockelée-Morvan et al. (1984) first questioned this notion based on remote observations of comet IRAS-Araki-Alcock. They reported an upper limit for the HCN production rate which was smaller than the CN production rate previously derived by A’Hearn et al. (1983). Even today, this discrepancy observed for some comets is not resolved although many alternative parents have been suggested. Among the volatile candidates, cyanogen (NCCN), cyanoacetylene (HC<sub>3</sub>N) and acetonitrile (CH<sub>3</sub>CN), according to Fray et al. (2005), are the most promising ones. While cyanoacetylene and acetonitrile are known to be present in trace amounts in comets, as reported for comet Hale-Bopp by Bockelée-Morvan et al. (2000) and for comet 67P/Churyumov-Gerasimenko by Le Roy et al. (2015) and Rubin et al. (2019), the abundance of cyanogen in comets is unknown. Altwegg et al. (2019) were the first to mention its detection in the inner coma of comet 67P/Churyumov-Gerasimenko, target of ESA’s Rosetta mission.</p> <p>In this work, we track the signatures of cyanogen in the ROSINA/DFMS (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis/ Double Focusing Mass Spectrometer; Balsiger et al. (2007)) data, collected during the Rosetta mission phase. We derive abundances relative to water for three distinct periods, indicating that cyanogen is not abundant enough to explain the CN production in comet 67P together with HCN. Our findings are consistent with the non-detection of cyanogen in the interstellar medium.</p> <p> </p> <p>A’Hearn M.F., Millis R.L., 1983, IAU Circ., 3802</p> <p>Altwegg K., Balsiger H., Fuselier S.A., 2019, Annu. Rev. Astron. Astrophys., 57, 113–55</p> <p>Balsiger H. et al., 2007, Space Science Reviews, 128, 745-801</p> <p>Bockelée-Morvan D., Crovisier J., Baudry A., Despois D., Perault M., Irvine W.M., Schloerb F.P., Swade D., 1984, Astron. Astrophys., 141, 411-418</p> <p>Bockelée-Morvan et al., 2000, Astron. Astrophys., 353, 1101–1114.</p> <p>Fray N., Bénilan Y., Cottin H., Gazeau M.-C., Crovisier J., 2005, Planetary and Space Science, 53, 1243-1262</p> <p>Le Roy L. et al., 2015, Astron. Astrophys., 583, A1</p> <p>Rubin M. et al., 2019, MNRAS, 489, 594-607</p>

scholarly journals First in situ detection of the CN radical in comets and evidence for a distributed source

2020 ◽  
Vol 498 (2) ◽  
pp. 2239-2248
Author(s):  
Nora Hänni ◽  
Kathrin Altwegg ◽  
Boris Pestoni ◽  
Martin Rubin ◽  
Isaac Schroeder ◽  
...  
Keyword(s):  
Spatial Information ◽  
Distributed Source ◽  
Definitive Answer ◽  
Double Focusing ◽  
In Situ Detection ◽  
First Time ◽  
Derived Data ◽  
Cn Radicals ◽  
Comet 67P

ABSTRACT Although the debate regarding the origin of the cyano (CN) radical in comets has been ongoing for many decades, it has yielded no definitive answer to date. CN could previously only be studied remotely, strongly hampering efforts to constrain its origin because of very limited spatial information. Thanks to the European Space Agency's Rosetta spacecraft, which orbited comet 67P/Churyumov–Gerasimenko for 2 yr, we can investigate, for the first time, CN around a comet at high spatial and temporal resolution. On board Rosetta's orbiter module, the high-resolution double-focusing mass spectrometer DFMS, part of the ROSINA instrument suite, analysed the neutral volatiles (including HCN and the CN radical) in the inner coma of the comet throughout that whole 2-yr phase and at variable cometocentric distances. From a thorough analysis of the full-mission data, the abundance of CN radicals in the cometary coma has been derived. Data from a close flyby event in 2015 February indicate a distributed origin for the CN radical in comet 67P/Churyumov–Gerasimenko.

scholarly journals Evaluation of the Nutrient Composition, In Vitro Fermentation Characteristics, and In Situ Degradability of Amaranthus caudatus, Amaranthus cruentus, and Amaranthus hypochondriacus in Cattle

Animals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Kim Margarette C. Nogoy ◽  
Jia Yu ◽  
Young Gyu Song ◽  
Shida Li ◽  
Jong-Wook Chung ◽  
...  
Keyword(s):  
Crude Protein ◽  
Dry Matter ◽  
Gas Production ◽  
Nutrient Composition ◽  
Neutral Detergent Fiber ◽  
Amaranthus Cruentus ◽  
Amaranthus Caudatus ◽  
Amaranthus Hypochondriacus

The amaranth plants showed high potential feed value as forage for ruminants. An in-depth study of this plant, particularly in cattle, will help extend its utilization as an alternative protein and fiber feed source in cattle feeding. In this study, the nutrient compositions of three different species of amaranth, Amaranthus caudatus L., Amaranthus cruentus L., and Amaranthus hypochondriacus L.—two varieties for each species, A.ca 74, A.ca 91, A.cu 62, A.cu 66, A. hy 30, and A. hy 48—were evaluated. The in vitro technique was used to evaluate the fermentation characteristics such as total gas production, total volatile fatty acids (VFA) concentration, pH, and ammonia concentration of the rumen fluid. Moreover, the effective degradabilities of dry matter (EDDM) and crude protein (EDCP) of the amaranth forages were determined through in situ bag technique. The amaranth forages: A. caudatus, A. cruentus, and A. hypochondriacus showed better nutritive value than the locally produced forages in Chungcheong province of Korea. The CP of the amaranth ranged from 11.95% to 14.19%, and the neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents ranged from 45.53% to 70.88% and 34.17% to 49.83%, respectively. Among the amaranth varieties, A. hypochondriacus 48 showed the most excellent ruminant feed nutrient quality (CP, 14.19%; NDF, 45.53%; and ADF, 34.17%). The effective degradabilities of dry matter (EDDM; 33–56%) and crude protein EDCP (27–59%) of the amaranth were lower compared to other studies, which could be due to the maturity stage at which the forages were harvested. Nonetheless, A. hypochondriacus 48 showed the highest EDDM (56.73%) and EDCP (59.09%). The different amaranth species did not differ greatly in terms of total VFA concentration or molar proportions, total gas production, or ammonia-N concentration. The high nutrient composition, and highly effective degradability of dry matter and crude protein, coupled with the favorable fermentation characteristics, suggest that the amaranth forages showed good to excellent feed quality for cattle.

scholarly journals Magmatic flare-up causes crustal thickening at the transition from subduction to continental collision

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Carlos E. Ganade ◽  
Pierre Lanari ◽  
Daniela Rubatto ◽  
Joerg Hermann ◽  
Roberto F. Weinberg ◽  
...  
Keyword(s):  
Production Rate ◽  
Continental Margin ◽  
Subduction Zones ◽  
Continental Collision ◽  
Crustal Thickening ◽  
Time Intervals ◽  
West Gondwana ◽  
Continental Arc ◽  
Order Of Magnitude

AbstractAbove subduction zones, magma production rate and crustal generation can increase by an order of magnitude during narrow time intervals known as magmatic flare-ups. However, the consequences of these events in the deep arc environment remain poorly understood. Here we use petrological and in-situ zircon dating techniques to investigate the root of a continental arc within the collisional West Gondwana Orogen that is now exposed in the Kabyé Massif, Togo. We show that gabbros intruded 670 million years ago at 20–25 km depth were transformed to eclogites by 620 million years ago at 65–70 km depth. This was coeval with extensive magmatism at 20–40 km depth, indicative of a flare-up event which peaked just prior to the subduction of the continental margin. We propose that increased H2O flux from subduction of serpentinized mantle in the hyper-extended margin of the approaching continent was responsible for the increased magma productivity and crustal thickening.

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