Gas-grain chemistry in protosolar nebula and composition of comets

1994 ◽  
Author(s):  
Zdeněk Moravec ◽  
Vladimír Vanysek
Keyword(s):  
Protosolar Nebula

Dynamics of comets in the collapsing protosolar nebula

1999 ◽  
Vol 173 ◽  
pp. 45-50
Author(s):  
L. Neslušan
Keyword(s):  
Solar System ◽  
Velocity Distribution ◽  
Oort Cloud ◽  
Interstellar Clouds ◽  
Protosolar Nebula ◽  
Moving Bodies

AbstractComets are created in the cool, dense regions of interstellar clouds. These macroscopic bodies take place in the collapse of protostar cloud as mechanically moving bodies in contrast to the gas and miscroscopic dust holding the laws of hydrodynamics. In the presented contribution, there is given an evidence concerning the Solar system comets: if the velocity distribution of comets before the collapse was similar to that in the Oort cloud at the present, then the comets remained at large cloud-centric distances. Hence, the comets in the solar Oort cloud represent a relict of the nebular stage of the Solar system.

Thermal and dynamical effects around rocklines in the innermost regions of the protosolar nebula

2021 ◽  
Author(s):  
Artyom Aguichine ◽  
Olivier Mousis ◽  
Bertrand Devouard ◽  
Thomas Ronnet
Keyword(s):  
Protosolar Nebula

scholarly journals Disk Chemistry and Cometary Composition

2005 ◽  
Vol 13 ◽  
pp. 518-521 ◽  
Author(s):  
A. J. Markwick ◽  
S. B. Charnley
Keyword(s):  
Solid State ◽  
Theoretical Study ◽  
Carbon Chain ◽  
Radial Variation ◽  
Chemical Processing ◽  
State Distribution ◽  
Physical Conditions ◽  
Short Period ◽  
Apparent Variation ◽  
Protosolar Nebula

AbstractWe describe a theoretical study of protoplanetary disk chemistry. By considering physical conditions similar to that of the protosolar nebula, we attempt to assess the contribution made by material from the cooler nebular regions to cometesimal composition. Calculations are presented which determine the spatial and temporal chemistry of the gas and dust within the 5-40 AU comet-forming region of the nebula. We show that there is little radial variation in the solid-state distribution of some molecules which could potentially be parents of the carbon-chain species observed in comets. We conclude that the apparent variation in abundance of C2 and C3 between long- and short-period comets is the result of chemical processing during their lifetimes and not differences in composition at the time of formation.

scholarly journals Identification of chondritic krypton and xenon in Yellowstone gases and the timing of terrestrial volatile accretion

2020 ◽  
Vol 117 (25) ◽  
pp. 13997-14004 ◽  
Author(s):  
Michael W. Broadley ◽  
Peter H. Barry ◽  
David V. Bekaert ◽  
David J. Byrne ◽  
Antonio Caracausi ◽  
...  
Keyword(s):  
Mantle Plume ◽  
Noble Gases ◽  
Noble Gas ◽  
Mid Ocean Ridge ◽  
Mantle Sources ◽  
Source Mantle ◽  
Morb Source ◽  
Protosolar Nebula ◽  
Ocean Ridge ◽  
Yellowstone Caldera

Identifying the origin of noble gases in Earth’s mantle can provide crucial constraints on the source and timing of volatile (C, N, H2O, noble gases, etc.) delivery to Earth. It remains unclear whether the early Earth was able to directly capture and retain volatiles throughout accretion or whether it accreted anhydrously and subsequently acquired volatiles through later additions of chondritic material. Here, we report high-precision noble gas isotopic data from volcanic gases emanating from, in and around, the Yellowstone caldera (Wyoming, United States). We show that the He and Ne isotopic and elemental signatures of the Yellowstone gas requires an input from an undegassed mantle plume. Coupled with the distinct ratio of129Xe to primordial Xe isotopes in Yellowstone compared with mid-ocean ridge basalt (MORB) samples, this confirms that the deep plume and shallow MORB mantles have remained distinct from one another for the majority of Earth’s history. Krypton and xenon isotopes in the Yellowstone mantle plume are found to be chondritic in origin, similar to the MORB source mantle. This is in contrast with the origin of neon in the mantle, which exhibits an isotopic dichotomy between solar plume and chondritic MORB mantle sources. The co-occurrence of solar and chondritic noble gases in the deep mantle is thought to reflect the heterogeneous nature of Earth’s volatile accretion during the lifetime of the protosolar nebula. It notably implies that the Earth was able to retain its chondritic volatiles since its earliest stages of accretion, and not only through late additions.

scholarly journals Isotopic Ratios in Comets

1991 ◽  
Vol 116 (2) ◽  
pp. 879-895 ◽  
Author(s):  
V. Vanysek
Keyword(s):  
Isotopic Ratio ◽  
Chemical Fractionation ◽  
Interstellar Clouds ◽  
Outer Planets ◽  
Carbon Isotopic Ratio ◽  
Carbon Isotopic ◽  
Nuclear Species ◽  
Carbon Reservoir ◽  
Protosolar Nebula ◽  
The Individual

Abstract.The isotopic abundances depend on the universal evolution of elements and on the individual history of particular objects. Since it is believed that unprocessed material of the solar nebula is preserved in comets, the data concerning the abundance of stable isotopes in these primitive bodies are of some importance in the cosmological context. The present status of this problem is reviewed. The reliability of results for nuclear species with cosmological and cosmogonical implications, such as D/H, C 12/13, N 14/15, O 16/18, and Mg 24/25/26, is discussed. Significant variation is found for the isotopic abundance of carbon, depending upon which carbon reservoir is sampled. Deuterium is probably enhanced relative to the interstellar ratio. For other isotopes, the ratios are close to those of the terrestrial data. The tendency of the D/H ratio to be at higher values indicates a low temperature in the environment of the comet’s formation, and, together with similar effects in the outer planets, suggests that there were two different primordial reservoirs of deuterium in the solar system. The 12C/13C ratio inferred from in situ mass spectrometry of the dust, as well as from the ground-based optical spectra of the Swan band, tends to be approximately equal to the average terrestrial ratio (89) or larger. Recent results obtained from the CN band provide a significantly lower value (about 65), which corresponds to the carbon isotopic ratio in the diffuse interstellar clouds. The enhancement of deuterium and the possible differences of the carbon isotopic ratio in different species and refractory material are indicative of chemical fractionation processes in the protosolar nebula.

Ice lines and the formation of Uranus and Neptune

2020 ◽  
Author(s):  
Olivier Mousis ◽  
Artyom Aguichine ◽  
Ravit Helled ◽  
Patrick Irwin ◽  
Jonathan I. Lunine
Keyword(s):  
Chemical Composition ◽  
Transport Model ◽  
Outer Region ◽  
Building Blocks ◽  
Planetary Formation ◽  
Physical Conditions ◽  
Elemental Abundances ◽  
Self Consistent ◽  
Protosolar Nebula ◽  
Do So

<p>We aim at investigating whether the chemical composition of the outer region of the protosolar nebula can be consistent with current estimates of the elemental abundances in the ice giants. To do so, we use a self-consistent evolutionary disc and transport model to investigate the time and radial distributions of H<sub>2</sub>O, CO, N<sub>2</sub>, and H<sub>2</sub>S, i.e., the main O-, C-, N, and S-bearing volatiles in the outer disc. We show that it is impossible to accrete a mixture composed of gas and solids from the disc with a C/H ratio presenting enrichments comparable to the measurements (70 times protosolar). We also find that the C/N and C/S ratios measured in Uranus and Neptune are compatible with those acquired by building blocks agglomerated from grains and pebbles condensed in the vicinities of N<sub>2</sub> and CO ice lines in the nebula. In contrast, the presence of protosolar C/N and C/S ratios in Uranus and Neptune would imply that their building blocks agglomerated from particles condensed at higher heliocentric distances. Our study demonstrates the importance of measuring the elemental abundances in the ice giant atmospheres, as they can be used to trace the planetary formation location and/or the chemical and physical conditions of the protosolar nebula.<span class="Apple-converted-space"> </span></p>

Rocklines of high temperature minerals in the protosolar nebula

2020 ◽  
Author(s):  
Artyom Aguichine ◽  
Olivier Mousis ◽  
Bertrand Devouard ◽  
Thomas Ronnet
Keyword(s):  
Bulk Composition ◽  
Formation Mechanisms ◽  
Refractory Materials ◽  
Large Core ◽  
Disk Model ◽  
One Dimensional ◽  
Iron Sulfur ◽  
Cosmic Spherules ◽  
Protosolar Nebula ◽  
Do So

<p>In our solar system, terrestrial planets and meteoritical matter exhibit various bulk compositions. To understand this variety of compositions, formation mechanisms of meteorites are usually investigated via a thermodynamic approach that neglect the processes of transport throughout the protosolar nebula. Here, we investigate the role played by rocklines (condensation/sublimation lines of refractory materials) in the innermost regions of the protosolar nebula to compute the composition of particles migrating inward the disk as a function of time. To do so, we utilize a one-dimensional  accretion disk model with a prescription for dust and vapor transport, sublimation and recondensation of refractory materials (ferrosilite, enstatite, fayalite, forsterite, iron sulfur, kamacite and nickel). We find that the diversity of the bulk composition of cosmic spherules can be explained by their formation close to rocklines, suggesting that solid matter is concentrated in the vicinity of these sublimation/condensation fronts. Although our model relies a lot on the number of considered species and the availability of thermodynamic data governing state change, it suggests that rocklines played a major role in the formation of small and large bodies in the innermost regions of the protosolar nebula. The results of our model are consistent with the composition of chondrules and cosmic spherules. Our model gives insights on the mechanisms that might have contributed to the formation of Mercury's large core.</p>

TRAPPING OF NOBLE GASES BY RADIATIVE ASSOCIATION WITH ${{\rm{H}}}_{3}^{+}$ IN THE PROTOSOLAR NEBULA

2016 ◽  
Vol 821 (2) ◽  
pp. L33 ◽  
Author(s):  
F. Pauzat ◽  
M-C. Bacchus-Montabonel ◽  
Y. Ellinger ◽  
O. Mousis
Keyword(s):  
Noble Gases ◽  
Radiative Association ◽  
Protosolar Nebula

scholarly journals Halogens as tracers of protosolar nebula material in comet 67P/Churyumov–Gerasimenko

2017 ◽  
Vol 472 (2) ◽  
pp. 1336-1345 ◽  
Author(s):  
Frederik Dhooghe ◽  
Johan De Keyser ◽  
Kathrin Altwegg ◽  
Christelle Briois ◽  
Hans Balsiger ◽  
...  
Keyword(s):  
Protosolar Nebula ◽  
Comet 67P
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