The rotational structure of the B–X system of sulfur dimers in the spectra of Comet Hyakutake (C/1996 B2)

Kim, Sang J.; A’Hearn, Michael F.; Wellnitz, D. D.; Meier, R.; Lee, Y.S.

doi:10.1016/j.icarus.2003.07.003

Cited by 26 publications

(16 citation statements)

References 22 publications

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“…Interestingly, it has been claimed that the S 2 detection in comets (A'hearn et al 1983;Krishna Swamy & Wallis 1987;Laffont et al 1998;Kim et al 2003;Boice & Reylé 2005), and notably in 67P/C-G (Le Roy et al 2015), is by itself a counter argument against the clathration hypothesis because its short lifetime in cometary coma due to photolysis, typically a few hundred seconds in the gas phase, would prevent its desorption from amorphous ice and its subsequent trapping in clathrate hydrates or condensation at lower PSN temperatures (Calmonte et al 2016). However, this statement would not apply to comets if, similarly to O 2 , S 2 formed from the radiolysis of S-bearing molecules embedded in ice grains.…”

Section: Discussionmentioning

confidence: 99%

Noble Gas Abundance Ratios Indicate the Agglomeration of 67P/Churyumov–Gerasimenko from Warmed-up Ice

Mousis

Ronnet

Lunine

et al. 2018

ApJL

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The origin of cometary volatiles remains a major open question in planetary science. Comets may have either agglomerated from crystalline ices condensed in the protosolar nebula (PSN) or from amorphous ice originating from the molecular cloud and interstellar medium. Here, based on the recent argon, krypton, and xenon measurements performed by the ROSINA mass spectrometer on board the European Space Agency's Rosetta spacecraft in the coma of 67P/Churyumov-Gerasimenko, we show that these noble gas relative abundances can be explained if the comet's building blocks formed from a mixture of gas and H 2 O grains resulting from the annealing of pristine amorphous ice (i.e., originating from the presolar cloud) in the PSN. In this scenario, the different volatiles released during the amorphous-to-crystalline ice phase transition would have been subsequently trapped at lower temperatures in stoichiometric hydrate or clathrate hydrate forms by the crystalline water ice generated by the transition. Once crystalline water was completely consumed by clathration in the ∼25-80 K temperature range, the volatile species remaining in the gas phase would have formed pure condensates at lower temperatures. The formation of clathrates hydrates and pure condensates to explain the noble gas relative abundances is consistent with a proposed interstellar origin of molecular oxygen detected in 67P/Churyumov-Gerasimenko, and with the measured molecular nitrogen depletion in comets.

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Section: Discussionmentioning

confidence: 99%

Noble Gas Abundance Ratios Indicate the Agglomeration of 67P/Churyumov–Gerasimenko from Warmed-up Ice

Mousis

Ronnet

Lunine

et al. 2018

ApJL

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“…This molecule was first detected in the UV spectra of comet C/1983 H1 (Ahearn et al 1983). Since then, S 2 has been identified in many comets (Swamy & Wallis 1987;Laffont et al 1998;Kim et al 2003). Recently the ROSINA mass spectrometer on board the Rosetta spacecraft detected S 2 at a distance of 3.15 au from the Sun, with an abundance of ∼10 −5 compared to water (Le Roy et al 2015).…”

Section: Sulfur Irradiation Products In Cometary Materialsmentioning

confidence: 99%

Production of Sulfur Allotropes in Electron Irradiated Jupiter Trojans Ice Analogs

Mahjoub

Poston

Blacksberg

et al. 2017

ApJ

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In this paper, we investigate sulfur chemistry in laboratory analogs of Jupiter Trojans and Kuiper Belt Objects (KBOs). Electron irradiation experiments of CH 3 OH-NH 3 -H 2 O and H 2 S-CH 3 OH-NH 3 -H 2 O ices were conducted to better understand the chemical differences between primordial planetesimals inside and outside the sublimation line of H 2 S. The main goal of this work is to test the chemical plausibility of the hypothesis correlating the color bimodality in Jupiter Trojans with sulfur chemistry in the incipient solar system. Temperature programmed desorption (TPD) of the irradiated mixtures allows the detection of small sulfur allotropes (S 3 and S 4 ) after the irradiation of H 2 S containing ice mixtures. These small, red polymers are metastable and could polymerize further under thermal processing and irradiation, producing larger sulfur polymers (mainly S 8 ) that are spectroscopically neutral at wavelengths above 500 nm. This transformation may affect the spectral reflectance of Jupiter Trojans in a different way compared to KBOs, thereby providing a useful framework for possibly differentiating and determining the formation and history of small bodies. Along with allotropes, we report the production of organosulfur molecules. Sulfur molecules produced in our experiment have been recently detected by Rosetta in the coma of 67P/Churyumov-Gerasimenko. The very weak absorption of sulfur polymers in the infrared range hampers their identification on Trojans and KBOs, but these allotropes strongly absorb light at UV and Visible wavelengths. This suggests that high signal-to-noise ratio UV-Vis spectra of these objects could provide new constraints on their presence.

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“…The observational circumstances are given in Table 1, which is adapted from Meier et al (1998), who also provide more extensive details. Analyses of other results from the spectra were presented by Meier et al (1998), by Kim et al (2003), and by A' Hearn et al (2014). Meier et al also discuss the reduction of the data.…”

Section: Observationsmentioning

confidence: 99%

Prompt Emission by Oh in Comet Hyakutake

A’Hearn

Swamy

Wellnitz

et al. 2015

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Laboratory studies predict that the photo-dissociation of H 2 O by solar Ly a photons in the comae of comets should lead to a small percentage of OH in high rotational states of the A 2 S + electronic state. These states should promptly emit a near-ultraviolet (near-UV) photon in a transition to the X 2 P state. From there, the radicals decay to the lowest rotational states by direct rotational transitions and via ro-vibrational cascade in the 1-0 vibrational band, all within the X 2 P state. Normally in Earth-based observations the lines are extremely weak compared to the fluorescence of OH in sunlight. Since the prompt emission rate is directly proportional to the column density of water, whereas the fluorescent emission of OH is proportional to the column density of OH, the lines due to prompt emission are relatively strongest very close to the nucleus, a region not often accessible from Earth. We report here the first spectrally resolved detection of near-UV prompt emission by cometary OH, as seen in the bright comet Hyakutake (C/1996 B2), on the day of its closest approach to Earth. All the expected doublets are seen, in both the P and Q branches, up to rotational quantum number N′ = 22 with relative strengths in good agreement with the laboratory results. The fluxes of the lines are in agreement with what one expects from the various measurements of the water production rate of the comet, including that deduced from the OH fluorescent lines in these spectra.

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The rotational structure of the B–X system of sulfur dimers in the spectra of Comet Hyakutake (C/1996 B2)

Cited by 26 publications

References 22 publications

Noble Gas Abundance Ratios Indicate the Agglomeration of 67P/Churyumov–Gerasimenko from Warmed-up Ice

Noble Gas Abundance Ratios Indicate the Agglomeration of 67P/Churyumov–Gerasimenko from Warmed-up Ice

Production of Sulfur Allotropes in Electron Irradiated Jupiter Trojans Ice Analogs

Prompt Emission by Oh in Comet Hyakutake

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