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

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.

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In-situ detection of cometary cyanogen (NCCN)

10.5194/epsc2020-397 ◽

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

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). Bockel&#233;e-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&#8217;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 (HC3N) and acetonitrile (CH3CN), 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 Bockel&#233;e-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&#8217;s Rosetta mission. 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. &#160; A&#8217;Hearn M.F., Millis R.L., 1983, IAU Circ., 3802 Altwegg K., Balsiger H., Fuselier S.A., 2019, Annu. Rev. Astron. Astrophys., 57, 113&#8211;55 Balsiger H. et al., 2007, Space Science Reviews, 128, 745-801 Bockel&#233;e-Morvan D., Crovisier J., Baudry A., Despois D., Perault M., Irvine W.M., Schloerb F.P., Swade D., 1984, Astron. Astrophys., 141, 411-418 Bockel&#233;e-Morvan et al., 2000, Astron. Astrophys., 353, 1101&#8211;1114. Fray N., B&#233;nilan Y., Cottin H., Gazeau M.-C., Crovisier J., 2005, Planetary and Space Science, 53, 1243-1262 Le Roy L. et al., 2015, Astron. Astrophys., 583, A1 Rubin M. et al., 2019, MNRAS, 489, 594-607

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

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2482 ◽

2019 ◽

Vol 489 (4) ◽

pp. 4734-4740 ◽

Cited By ~ 4

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.

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

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2643 ◽

2020 ◽

Vol 498 (3) ◽

pp. 3995-4004 ◽

Cited By ~ 2

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.

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

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833806 ◽

2019 ◽

Vol 630 ◽

pp. A29 ◽

Cited By ~ 8

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.

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Analyzing 67P’s dusty coma

10.5194/egusphere-egu21-1719 ◽

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

While the volatile species in comet 67P/Churyumov-Gerasimenko&#8217;s coma have been analyzed in great spatial and temporal detail, e.g., Rubin et al. (2019) or L&#228;uter 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).Complementary information on 67P&#8217;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.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&#8217;s dusty coma.&#160;Altwegg et al., 2020, Nat. Astron., 4, 533-540. Altwegg et al., 2019, Annu. Rev. Astron. Astrophys., 57, 113-55. Balsiger H. et al., 2007, Space Sci. Rev., 128, 745-801. L&#228;uter et al., 2020, MNRAS, 498, 3, 3995-4004. Rubin et al., 2019, MNRAS, 489, 594-607. Vincent et al., 2016, MNRAS, 462 (Suppl_1), 184-194.

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Ingredients for solar-like systems: protostar IRAS 16293-2422 B versus comet 67P/Churyumov–Gerasimenko

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2430 ◽

2019 ◽

Vol 490 (1) ◽

pp. 50-79 ◽

Cited By ~ 10

Author(s):

Maria N Drozdovskaya ◽

Ewine F van Dishoeck ◽

Martin Rubin ◽

Jes K Jørgensen ◽

Kathrin Altwegg

Keyword(s):

Bulk Composition ◽

High Sensitivity ◽

Building Blocks ◽

In Situ Monitoring ◽

The Earth ◽

Low Mass ◽

Line Survey ◽

First Time ◽

Comet 67P

ABSTRACT Our modern day Solar System has 4.6 × 109 yr of evolution behind it with just a few relics of its birth conditions remaining. Comets are thought to be some of the most pristine tracers of the initial ingredients that were combined to produce the Earth and the other planets. Other low-mass protostars may be analogous to our proto-Sun and hence, could be used to study the building blocks necessary to form Solar-like systems. This study tests this idea on the basis of new high sensitivity, high spatial resolution ALMA data on the protoplanetary disc-scales (∼70 au) of IRAS 16293-2422 and the bulk composition of comet 67P/Churyumov-Gerasimenko, as determined for the first time with the unique in situ monitoring carried out by Rosetta. The comparative analysis of the observations from the Protostellar Interferometric Line Survey (PILS) and the measurements made with Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) shows that the relative abundances of CHO-, N-, and S-bearing molecules correlate, with some scatter, between protostellar and cometary data. A tentative correlation is seen for the first time for P- and Cl-bearing compounds. The results imply that the volatile composition of cometesimals and planetesimals is partially inherited from the pre- and protostellar phases of evolution.

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In Situ Detection of Kinetic-size Magnetic Holes in the Martian Magnetosheath

The Astrophysical Journal ◽

10.3847/1538-4357/ac2737 ◽

2021 ◽

Vol 922 (2) ◽

pp. 107

Author(s):

S. Y. Huang ◽

R. T. Lin ◽

Z. G. Yuan ◽

K. Jiang ◽

Y. Y. Wei ◽

...

Keyword(s):

Magnetic Field ◽

Energy Dissipation ◽

Field Strength ◽

Space Plasmas ◽

Mars Atmosphere ◽

Planetary Environments ◽

Space Environments ◽

In Situ Detection ◽

First Time

Abstract Depression in magnetic field strength with a scale below one proton gyroradius is referred to as a kinetic-size magnetic hole (KSMH). KSMHs are frequently observed near Earth’s space environments and are thought to play an important role in electron energization and energy dissipation in space plasmas. Recently, KSMHs have been evidenced in the Venusian magnetosheath. However, observations of KSMHs in other planetary environments are still lacking. In this study, we present the in situ detection of KSMHs in the Martian magnetosheath using Mars Atmosphere and Volatile EvolutioN (MAVEN) for the first time. The distribution of KSMHs is asymmetry in the southern–northern hemisphere and no obvious asymmetry in the dawn–dusk hemisphere. The observed KSMHs are accompanied by increases in the electron fluxes in the perpendicular direction, indicating the cues of trapped electrons and the formation of electron vortices inside KSMHs. These features are similar to the observations in the Earth’s magnetosheath and magnetotail plasma sheet and the Venusian magnetosheath. This implies that KSMHs are a universal magnetic structure in space.

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In Situ Detection of Organics in the Comet 67P/Churyumov-Gerasimenko

Chem ◽

10.1016/j.chempr.2016.11.001 ◽

2016 ◽

Vol 1 (6) ◽

pp. 824-826 ◽

Cited By ~ 2

Author(s):

Alexandre Bergantini ◽

Ralf I. Kaiser

Keyword(s):

In Situ Detection ◽

Comet 67P

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An N-nitrosation reactivity-based two-photon fluorescent probe for the specific in situ detection of nitric oxide

Chemical Science ◽

10.1039/c7sc00416h ◽

2017 ◽

Vol 8 (6) ◽

pp. 4533-4538 ◽

Cited By ~ 66

Author(s):

Zhiqiang Mao ◽

Hong Jiang ◽

Zhen Li ◽

Cheng Zhong ◽

Wei Zhang ◽

...

Keyword(s):

Nitric Oxide ◽

Fluorescent Probe ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Specific Detection ◽

Two Photon Microscopy ◽

Two Photon ◽

In Situ Detection ◽

First Time

An N-nitrosation reactivity-based two-photon fluorescent probe for the specific detection of NO was rationally designed, prepared, and applied in the in situ detection of nitric oxide in ischemia reperfusion injury mouse model under two-photon microscopy for the first time.

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The cometary matter between volatiles and macromolecules

10.5194/epsc2021-681 ◽

2021 ◽

Author(s):

Nora Hänni ◽

Kathrin Altwegg ◽

Daniel Müller ◽

Boris Pestoni ◽

Martin Rubin ◽

...

Keyword(s):

Mass Spectrometer ◽

Mass Range ◽

Degree Of Saturation ◽

Full Data ◽

Data Set ◽

Insoluble Organic Matter ◽

Rosetta Mission ◽

Double Focusing ◽

First Time ◽

Comet 67P

Small and volatile molecules are the most abundant constituents of a comet&#8217;s neutral coma. Thanks to ESA&#8217;s Rosetta mission, the neutral coma of comet 67P/Churyumov-Gerasimenko (67P hereafter) has been analyzed in great spatial and temporal detail, e.g., by Rubin et al. (2019) or by L&#228;uter et al. (2020). However, the Double Focusing Mass Spectrometer (DFMS) &#8211; part of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA; Balsiger et al. 2007) &#8211; delivered data which contains information about the transition region between volatiles and macromolecular matter. Manual fitting of individual spectra allows to resolve pure hydrocarbon from heteroatom-bearing species also in the higher mass-range of the instrument, up to mass-to-charge (m/z) ratios of 140. While Altwegg et al. (2019) have reported tentative detections of some heavier species like benzoic acid or naphthalene, spectra of m/z>70 have not been investigated systematically. Here, we will present preliminary results from the first comprehensive analysis of a full data set (from m/z=12 to m/z=140) collected on August 3, 2015. On this day, the comet was close to its perihelion and the dust activity, as seen by the OSIRIS camera (Vincent et al. 2016), was high. Probably due to sublimation of molecules from ejected and heated-up dust grains, ROSINA/DFMS registered many signals above m/z=70. Due to the problem of isomerism and the lack of reference data, we chose to follow a statistical approach for our analysis. Larger species tend to expose a lower degree of saturation and the H/C ratio seems to approach that of highly unsaturated insoluble organic matter (IOM), cf., e.g., Sandford 2008. Although we cannot identify individual molecules in the complex gas mixture that makes up for the cometary coma, we are able to characterize for the first time the larger organic species that bridge the small volatiles and the macromolecular matter observed in 67P&#8217;s dust by the Rosetta secondary ion mass spectrometer COSIMA (Fray et al. 2016). &#160; &#160; &#160; Altwegg et al., 2019, Annu. Rev. Astron. Astrophys., 57, 113-55. Balsiger H. et al., 2007, Space Sci. Rev., 128, 745-801. Fray et al., 2016, Nature, 538, 72-74. L&#228;uter et al., 2020, MNRAS, 498, 3, 3995-4004. Rubin et al., 2019, MNRAS, 489, 594-607. Sandford, 2008, Annu. Rev. Anal. Chem. 1, 549&#8211;78. Vincent et al., 2016, MNRAS, 462 (Suppl_1), 184-194.

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