Nucleation and condensation in the primitive solar nebula

Cameron, A. G. W.; Fegley, M. B.

doi:10.1016/0019-1035(82)90165-8

Cited by 56 publications

(19 citation statements)

References 8 publications

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“…To give one example, for the cosmic (solar or stellar) C/H abundance ratio, expressed in ppm, one finds values of 417 (Cameron & Fegley 1982), 363 (Anders & Grevesse 1989), 398 (Grevesse et al 1993), 330 (Grevesse & Sauval 1998), 391 (Holweger 2001), 245 (Asplund & Garcia-Perez 2004), 269 (Asplund et al 2009), 316 (Caffau et al 2010), 245 (Lodders 2010), and 214 (Nieva & Przybilla 2012). Towards 21 sight lines, Parvathi et al (2012) derive C/H ratios between 69 and 414 ppm.…”

Section: Element Abundancesmentioning

confidence: 99%

Dust in the diffuse interstellar medium

Siebenmorgen

Вощинников

Bagnulo

2014

A&A

112

123

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We present a model for the diffuse interstellar dust that explains the observed wavelength-dependence of extinction, emission, and the linear and circular polarisation of light. The model is set up with a small number of parameters. It consists of a mixture of amorphous carbon and silicate grains with sizes from the molecular domain of 0.5 up to about 500 nm. Dust grains with radii larger than 6 nm are spheroids. Spheroidal dust particles have a factor 1.5-3 greater absorption cross section in the far-infrared than spherical grains of the same volume do. Mass estimates derived from submillimetre observations that ignore this effect are overestimated by the same amount. In the presence of a magnetic field, spheroids may be partly aligned and polarise light. We find that polarisation spectra help to determine the upper particle radius of the otherwise rather unconstrained dust size distribution. Stochastically heated small grains of graphite, silicates, and polycyclic aromatic hydrocarbons (PAHs) are included. We tabulate parameters for PAH emission bands in various environments. They show a trend with the hardness of the radiation field that can be explained by the ionisation state or hydrogenation coverage of the molecules. For each dust component its relative weight is specified so that absolute element abundances are not direct input parameters. The model is compared to the average properties of the Milky Way, which seem to represent dust in the solar neighbourhood. It is then applied to specific sight lines towards four particular stars, with one of them located in the reflection nebula NGC 2023. For these sight lines, we present ultra-high signal-to-noise linear and circular spectro-polarimetric observations obtained with FORS at the VLT. Using prolate rather than oblate grains gives a better fit to observed spectra; the axial ratio of the spheroids is typically two and aligned silicates are the dominant contributors to the polarisation.

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Section: Element Abundancesmentioning

confidence: 99%

Dust in the diffuse interstellar medium

Siebenmorgen

Вощинников

Bagnulo

2014

A&A

112

123

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“…Such recycling has been investigated in the high-temperature regime by Morfill (1983), who presents a detailed discussion of such a process for higher-temperature condensates (e.g., chondrules and CAIs), and by Cameron and Fegley (1982), who discuss vertical cycling and the accretion of material of intermediate volatility.…”

Section: Volatile Recyclingmentioning

confidence: 99%

Formation of Icy Planetesimals in a Turbulent Solar Nebula

Supulver

Lin

2000

Icarus

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“…As solid condensates, type C's are related to type A's. Condensation of solids to form type C's can take place at the low total pressures (10-6-10 -4 atm) thought to have existed in the primitive solar nebula [58,59]. Forming liquids in the protoatmosphere of giant gaseous planets has been proposed [60], but this leads to the difficult dynamic problem of how to extract such condensates from the gravity field of a giant planet.…”

Section: Origin Of Type C Inclusions As Liquid Condensatesmentioning

confidence: 99%

The origin of type C inclusions from carbonaceous chondrites

Beckett

Grossman

1988

Earth and Planetary Science Letters

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Type C inclusions are plagioclase-rich, Ca-, Al-rich inclusions found in carbonaceous chondrites. They formed as solid condensates which were later melted in an event that destroyed the original condensate grains. Neither the melting event nor secondary alteration had a significant effect on bulk composition. Two stages in the condensation history can be discerned on the basis of major element bulk compositions. As in type A inclusions, the condensate phase assemblage originally consisted of melilite + spinel + perovskite + hibonite. Type C's were, however, significantly enriched in spinel relative to unaltered portions of most type A's. In contrast to type A's, condensate grains of spinel and melilite in type C's reacted partially with a coexisting gas to produce anorthite + diopside. One-half to two-thirds of the silica now in type C inclusions was introduced by this process. The reactions involving melilite and spinel that are predicted by equilibrium condensation calculations for a cooling gas of solar composition did not occur, probably due to kinetic constraints. Type C's may be related to Al-rich chondrules in ordinary chondrites by the addition of olivine and albite. Bulk compositions of Al-rich chondrules in enstatite chondrites are consistent with the addition of orthopyroxene and albite to type C inclusions. Thus, types A and C inclusions and Al-rich chondrules could represent sequences of condensates removed from interaction with the primitive solar nebula at progressively lower temperatures. If Al-rich chondrules represent the high-temperature component in chondritic material, then type C inclusions rather than the more common subgroups of CAIs could be the true parents of chondrites.

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Nucleation and condensation in the primitive solar nebula

Cited by 56 publications

References 8 publications

Dust in the diffuse interstellar medium

Dust in the diffuse interstellar medium

Formation of Icy Planetesimals in a Turbulent Solar Nebula

The origin of type C inclusions from carbonaceous chondrites

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