The CO 2 abundance in Comets C/2012 K1 (PanSTARRS), C/2012 K5 (LINEAR), and 290P/Jäger as measured with Spitzer

McKay, Adam; Kelley, Michael S. P.; Cochran, A. L.; Bodewits, Dennis; DiSanti, M. A.; Russo, N. Dello; Lisse, C. M.

doi:10.1016/j.icarus.2015.11.004

Cited by 21 publications

(15 citation statements)

References 52 publications

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“…Like Garradd (Combi et al, 2013;Bodewits et al, 2014), C/2012 K1 (PanSTARRS) is suspected of having an important icy grain halo before perihelion that likely dominates the water production rate. McKay et al (2016) suggest that there is evidence in the radial distribution of gas emission from 2012 K1 from a range of observations with different aperture sizes, showing that there is an important extended source of gas. Their results, derived from relatively large-aperture Swift/UVOT observations of OH, are consistent with both the much larger aperture SWAN results shown here and the ground-based OH observations by Knight and Schleicher (2014), but they see a trend when comparing production rates from much smaller aperture observations.…”

Section: Results Of Model Analyses For Each Cometmentioning

confidence: 90%

Water production activity of nine long-period comets from SOHO/SWAN observations of hydrogen Lyman-alpha: 2013–2016

Combi

Mäkinen

Bertaux

et al. 2018

Icarus

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Nine recently discovered long-period comets were observed by the Solar Wind Anisotropies Of these 9 comets 6 were long-period comets and 3 were possibly dynamically new. Water production rates were calculated from each of the 885 images using our standard time-resolved model that accounts for the whole water photodissociation chain, exothermic velocities and collisional escape of H atoms. For most of these comets there were enough observations over a broad enough range of heliocentric distances to calculate power-law fits to the variation of production rate with heliocentric distances for pre-and post-perihelion portions of the orbits.Comet C/2014 Q1 (PanSTARRS), with a perihelion distance of only ~0.3 AU, showed the most unusual variation of water production rate with heliocentric distance and the resulting active area variation, indicating that when the comet was within 0.7 AU its activity was dominated by the continuous release of icy grains and chunks, greatly increasing the active sublimation area by more than a factor of 10 beyond what it had at larger heliocentric distances. A possible interpretation suggests that a large fraction of the comet's mass was lost during the apparition.

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Section: Results Of Model Analyses For Each Cometmentioning

confidence: 90%

Water production activity of nine long-period comets from SOHO/SWAN observations of hydrogen Lyman-alpha: 2013–2016

Combi

Mäkinen

Bertaux

et al. 2018

Icarus

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“…In comets, planetary atmospheres, and interstellar ices, its abundance is a significant fraction (∼ 0.1 − 0.5) of that of water (e.g. Bergin et al 2005, Whittet et al 2009, McKay et al 2016, Hoang et al 2017. CO 2 ice is one of the main constituent of the icy mantles of dust grains ( Öberg et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Protonated CO2 in massive star-forming clumps

Fontani

Vagnoli

Padovani

et al. 2018

Monthly Notices of the Royal Astronomical Society: Letters

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Interstellar CO 2 is an important reservoir of carbon and oxygen, and one of the major constituents of the icy mantles of dust grains, but it is not observable directly in the cold gas because has no permanent dipole moment. Its protonated form, HOCO + , is believed to be a good proxy for gaseous CO 2 . However, it has been detected in only a few star-forming regions so far, so that its interstellar chemistry is not well understood. We present new detections of HOCO + lines in 11 high-mass star-forming clumps. Our observations increase by more than three times the number of detections in starforming regions so far. We have derived beam-averaged abundances relative to H 2 in between 0.3 and 3.8 × 10 −11 . We have compared these values with the abundances of H 13 CO + , a possible gas-phase precursor of HOCO + , and CH 3 OH, a product of surface chemistry. We have found a positive correlation with H 13 CO + , while with CH 3 OH there is no correlation. We suggest that the gas-phase formation route starting from HCO + plays an important role in the formation of HOCO + , perhaps more relevant than protonation of CO 2 (upon evaporation of this latter from icy dust mantles).

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“…. Molecular abundances relative to water present strong variations from comet to comet, and also vary along comet orbit (e.g., Biver & Bockelée-Morvan 2016;Ootsubo et al 2012;McKay et al 2015McKay et al , 2016. This chemical diversity is often interpreted as reflecting different formation conditions in the primitive solar nebula (e.g., A'Hearn et al 2012).…”

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confidence: 99%

Evolution of CO₂, CH₄, and OCS abundances relative to H₂O in the coma of comet 67P around perihelion fromRosetta/VIRTIS-H observations

Bockelée‐Morvan

Crovisier

Erard

et al. 2016

Mon. Not. R. Astron. Soc.

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Infrared observations of the coma of 67P/Churyumov-Gerasimenko were carried out from July to September 2015, i.e., around perihelion (13 August 2015, with the highresolution channel of the VIRTIS instrument onboard Rosetta. We present the analysis of fluorescence emission lines of H 2 O, CO 2 , 13 CO 2 , OCS, and CH 4 detected in limb sounding with the field of view at 2.7-5 km from the comet centre. Measurements are sampling outgassing from the illuminated southern hemisphere, as revealed by H 2 O and CO 2 raster maps, which show anisotropic distributions, aligned along the projected rotation axis. An abrupt increase of water production is observed six days after perihelion. In the mean time, CO 2 , CH 4 , and OCS abundances relative to water increased by a factor of 2 to reach mean values of 32 %, 0.47 %, and 0.18%, respectively, averaging post-perihelion data. We interpret these changes as resulting from the erosion of volatile-poor surface layers. Sustained dust ablation due to the sublimation of water ice maintained volatile-rich layers near the surface until at least the end of the considered period, as expected for low thermal inertia surface layers. The large abundance measured for CO 2 should be representative of the 67P nucleus original composition, and indicates that 67P is a CO 2 -rich comet. Comparison with abundance ratios measured in the northern hemisphere shows that seasons play an important role in comet outgassing. The low CO 2 /H 2 O values measured above the illuminated northern hemisphere are not original, but the result of the devolatilization of the uppermost layers.

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The CO 2 abundance in Comets C/2012 K1 (PanSTARRS), C/2012 K5 (LINEAR), and 290P/Jäger as measured with Spitzer

Abstract: Carbon dioxide is one of the most abundant ices present in comets and is therefore important for understanding cometary composition and activity. We

Cited by 21 publications

References 52 publications

Water production activity of nine long-period comets from SOHO/SWAN observations of hydrogen Lyman-alpha: 2013–2016

Water production activity of nine long-period comets from SOHO/SWAN observations of hydrogen Lyman-alpha: 2013–2016

Protonated CO2 in massive star-forming clumps

Evolution of CO₂, CH₄, and OCS abundances relative to H₂O in the coma of comet 67P around perihelion fromRosetta/VIRTIS-H observations

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The CO 2 abundance in Comets C/2012 K1 (PanSTARRS), C/2012 K5 (LINEAR), and 290P/Jäger as measured with Spitzer

Abstract: Carbon dioxide is one of the most abundant ices present in comets and is therefore important for understanding cometary composition and activity. We

Cited by 21 publications

References 52 publications

Water production activity of nine long-period comets from SOHO/SWAN observations of hydrogen Lyman-alpha: 2013–2016

Water production activity of nine long-period comets from SOHO/SWAN observations of hydrogen Lyman-alpha: 2013–2016

Protonated CO2 in massive star-forming clumps

Evolution of CO2, CH4, and OCS abundances relative to H2O in the coma of comet 67P around perihelion fromRosetta/VIRTIS-H observations

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Evolution of CO₂, CH₄, and OCS abundances relative to H₂O in the coma of comet 67P around perihelion fromRosetta/VIRTIS-H observations