New experimental sublimation energy measurements for some relevant astrophysical ices

Luna, R.; Satorre, M. Á.; Santonja, C.; Domingo, M.

doi:10.1051/0004-6361/201323249

Cited by 33 publications

(26 citation statements)

References 59 publications

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“…• CO, as an example of a volatile species, with a 7.3 kJ/mol desorption energy much less than that of water (Collings & McCoustra 2005;Luna et al 2014), experiences a first desorption from a water ice mixture at temperatures of 20-60 K, in agreement with its small desorption energy. A very small molecule like CO can also diffuse into the ice as it is slowly heated.…”

Section: Comet Grain Modelmentioning

confidence: 66%

See 1 more Smart Citation

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

Keyser

Dhooghe

Altwegg

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Rosetta has detected the presence of the hydrogen halides HF, HCl, and HBr in the coma of comet 67P/Churyumov-Gerasimenko. These species are known to freeze out on icy grains in molecular clouds. Analysis of the abundances of HF and HCl as a function of cometocentric distance suggests that these hydrogen halides are released both from the nucleus surface and off dust particles in the inner coma. We present three lines of evidence. First, the abundances of HF and HCl relative to the overall neutral gas in the coma appear to increase with distance, indicating that a net source must be present; since there is no hint at any possible parent species with sufficient abundances that could explain the observed levels of HF or HCl, dust particles are the likely origin. Second, the amplitude of the daily modulation of the halide-to-water density due to the rotation and geometry of 67P's nucleus and the corresponding surface illumination is observed to progressively diminish with distance and comet dust activity; this can be understood from the range of dust particle speeds well below the neutral gas expansion speed, which tends to smooth the coma density profiles. Third, strong halogen abundance changes detected locally in the coma cannot be easily explained from composition changes at the surface, while they can be understood from differences in local gas production from the dust particles.

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Section: Comet Grain Modelmentioning

confidence: 66%

“…• Species like CO 2 , with a desorption energy of 26 kJ/mol still less volatile than water (Luna et al 2014) but too large to diffuse into the ice, show multi-layer desorption in a broad temperature range around 80 K, again followed by desorption at 140 and 160 K, as these species are mixed into the ice matrix.…”

Section: Comet Grain Modelmentioning

confidence: 99%

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

Keyser

Dhooghe

Altwegg

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…For example, the values of the sublimation energies we use for H O 2 , NH 3 , CO 2 , and CO are 10%-20% higher than those derived from the very recent temperature programmed desorption experiments by Martín-Doménech et al (2014, see their Table 4). Luna et al (2014) compiled the sublimation energies of major cometary volatiles from different experimental methods, and showed that the published sublimation energies have a standard deviation of 14%, 8%, 11%, and 8% for NH 3 , CO 2 , CH 4 , and CO, respectively (see their Table 2 and Figures 4 and 5). Such uncertainties might be present in the vapor pressure data for other volatiles species.…”

Section: Equilibrium Vapor Pressuresmentioning

confidence: 99%

Sintering-Induced Dust Ring Formation in Protoplanetary Disks: Application to the Hl Tau Disk

Okuzumi

Momose

Sirono

et al. 2016

ApJ

377

349

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The latest observation of HL Tau by ALMA revealed spectacular concentric dust rings in its circumstellar disk. We attempt to explain the multiple ring structure as a consequence of aggregate sintering. Sintering is known to reduce the sticking efficiency of dust aggregates and occurs at temperatures slightly below the sublimation point of the constituent material. We present a dust growth model that incorporates sintering and use it to simulate global dust evolution due to sintering, coagulation, fragmentation, and radial inward drift in a modeled HL Tau disk. We show that aggregates consisting of multiple species of volatile ices experience sintering, collisionally disrupt, and pile up at multiple locations slightly outside the snow lines of the volatiles. At wavelengths of 0.87-1.3 mm, these sintering zones appear as bright, optically thick rings with a spectral slope of »2, whereas the non-sintering zones appear as darker, optically thinner rings of a spectral slope of »2.3-2.5. The observational features of the sintering and non-sintering zones are consistent with those of the major bright and dark rings found in the HL Tau disk, respectively. Radial pileup and vertical settling occur simultaneously if disk turbulence is weak and if monomers constituting the aggregates are m1 m in radius. For the radial gas temperature profile of = -T r 310 1 au K 0.57 ( ) , our model perfectly reproduces the brightness temperatures of the optically thick bright rings and reproduces their orbital distances to an accuracy of 30%.

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“…23.3-28.3 kJ mol −1 (He et al 2015). Quartz crystal microbalance techniques have also been used to investigate the sublimation of multilayer NH3 ice, yielding a sublimation energy of 31.8 kJ mol −1 (Luna et al 2014). In the case of silicate minerals incorporating one or other metal atoms, the resulting increase in potential adsorption sites would be expected to influence the adsorption energies of bound species.…”

Section: Introductionmentioning

confidence: 99%

Thermal desorption of ammonia from crystalline forsterite surfaces

Suhasaria¹,

Thrower²,

Zacharias³

2015

Mon. Not. R. Astron. Soc.

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The thermal desorption of ammonia (NH 3 ) from single crystal forsterite (010) has been investigated using temperature-programmed desorption. The effect of defects on the desorption process has been probed by the use of a rough cut forsterite surface prepared from the cleaved forsterite sample. Several approaches have been used to extract the desorption energy and pre-exponential factor describing the desorption kinetics. In the sub-monolayer coverage regime, the NH 3 desorption shows a broad distribution of desorption energies, indicating the presence of different adsorption sites, which results in an apparent coverage-dependent desorption energy. This distribution is sensitive to the surface roughness with the cut forsterite surface displaying a significantly broader distribution of desorption energies compared to the cleaved forsterite surface. The cut forsterite surface exhibits sites with desorption energies up to 62.5 kJ mol −1 in comparison to a desorption energy of up to 58.0 kJ mol −1 for the cleaved surface. Multilayer desorption is independent of the nature of the forsterite surface used, with a desorption energy of (25.8±0.9) kJ mol −1 . On astrophysically relevant heating timescales, the presence of a coverage dependent desorption energy distribution results in a lengthening of the NH 3 desorption time-scale by 5.9 × 10 4 yr compared to that expected for a single desorption energy. In addition, the presence of a larger number of high-energy adsorption sites on the rougher cut forsterite surface leads to a further lengthening of ca. 7000 yr.

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New experimental sublimation energy measurements for some relevant astrophysical ices

Cited by 33 publications

References 59 publications

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

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

Sintering-Induced Dust Ring Formation in Protoplanetary Disks: Application to the Hl Tau Disk

Thermal desorption of ammonia from crystalline forsterite surfaces

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