scholarly journals Oxygen isotopic heterogeneity in the early Solar System inherited from the protosolar molecular cloud

2020 ◽  
Vol 6 (42) ◽  
pp. eaay2724
Author(s):  
Alexander N. Krot ◽  
Kazuhide Nagashima ◽  
James R. Lyons ◽  
Jeong-Eun Lee ◽  
Martin Bizzarro
Keyword(s):  
Solar System ◽  
Molecular Cloud ◽  
Limited Range ◽  
Terrestrial Planets ◽  
Carbonaceous Chondrites ◽  
The Sun ◽  
Early Solar System ◽  
Isotopic Heterogeneity ◽  
Oxygen Isotopic ◽  
O 24

The Sun is 16O-enriched (Δ17O = −28.4 ± 3.6‰) relative to the terrestrial planets, asteroids, and chondrules (−7‰ < Δ17O < 3‰). Ca,Al-rich inclusions (CAIs), the oldest Solar System solids, approach the Sun’s Δ17O. Ultraviolet CO self-shielding resulting in formation of 16O-rich CO and 17,18O-enriched water is the currently favored mechanism invoked to explain the observed range of Δ17O. However, the location of CO self-shielding (molecular cloud or protoplanetary disk) remains unknown. Here we show that CAIs with predominantly low (26Al/27Al)0, <5 × 10−6, exhibit a large inter-CAI range of Δ17O, from −40‰ to −5‰. In contrast, CAIs with the canonical (26Al/27Al)0 of ~5 × 10−5 from unmetamorphosed carbonaceous chondrites have a limited range of Δ17O, −24 ± 2‰. Because CAIs with low (26Al/27Al)0 are thought to have predated the canonical CAIs and formed within first 10,000–20,000 years of the Solar System evolution, these observations suggest oxygen isotopic heterogeneity in the early solar system was inherited from the protosolar molecular cloud.

Boron Behavior During the Evolution of the Early Solar System: The First 180 Million Years

Elements ◽  
2017 ◽  
Vol 13 (4) ◽  
pp. 231-236 ◽  
Author(s):  
Charles K. Shearer ◽  
Steven B. Simon
Keyword(s):  
Solar System ◽  
Solar Nebula ◽  
Nuclear Reactions ◽  
Terrestrial Planets ◽  
The Sun ◽  
Planetary Formation ◽  
Light Elements ◽  
Early Solar System ◽  
Spallation Reactions ◽  
Magma Oceans

The behavior of boron during the early evolution of the Solar System provides the foundation for how boron reservoirs become established in terrestrial planets. The abundance of boron in the Sun is depleted relative to adjacent light elements, a result of thermal nuclear reactions that destroy boron atoms. Extant boron was primarily generated by spallation reactions. In the initial materials condensing from the solar nebula, boron was predominantly incorporated into plagioclase. Boron abundances in the terrestrial planets exhibit variability, as illustrated by B/Be. During planetary formation and differentiation, boron is redistributed by fluids at low temperature and during crystallization of magma oceans at high temperature.

Atmospheres as a clue to the early Solar System

1988 ◽  
Vol 325 (1587) ◽  
pp. 569-582 ◽  
Keyword(s):  
Solar System ◽  
Observational Data ◽  
Terrestrial Planets ◽  
The Sun ◽  
Early Solar System ◽  
Secondary Formation ◽  
Planets And Satellites

Conditions that could have applied in the environments of the major planets when they were forming make it possible that the present icy mantles of the larger satellites were then oceans and vapour atmospheres encasing silicate—ferrous cores. The major constituents are explored by comparison with the present atmospheres of the terrestrial planets. It is further suggested that the primary condensations during the formation of the Solar System were the Sun and the major planets, and that the terrestrial planets and satellites were a secondary formation. Some observational data are offered in support of the arguments and future tests are suggested.

scholarly journals Oxygen Isotopic Heterogeneity in the Solar System Inherited from the Protosolar Molecular Cloud

2020 ◽  
Author(s):  
Alexander N. Krot ◽  
Kazuhide Nagashima ◽  
James Lyons ◽  
Jeong-Eun Lee ◽  
Martin Bizzarro
Keyword(s):  
Solar System ◽  
Molecular Cloud ◽  
Isotopic Heterogeneity ◽  
Oxygen Isotopic

scholarly journals Evidence for Lunar-Type Objects in the Early Solar System

1974 ◽  
Vol 3 ◽  
pp. 475-481
Author(s):  
H. C. Urey
Keyword(s):  
Solar System ◽  
Volatile Compounds ◽  
Metallic Iron ◽  
Variable Mass ◽  
High Density ◽  
Terrestrial Planets ◽  
The Sun ◽  
Early Solar System ◽  
Solar Material ◽  
Silicate Materials

Objects of the solar system, in addition to the Sun, can be classified into four groups -the planets, objects of lunar mass, smaller objects of variable mass and the comets.If the solar proportion of gases relative to non-volatile compounds of the variety in the terrestrial planets, namely about 300 times the mass of these elements, were added to the terrestrial planets, they would have masses comparable to those of the major planets. Mercury is low in mass but has a high density, indicating that it has lost several times its mass of silicate materials relative to high density metallic iron. If this were restored and then the component of gases were added, it would also fall into the group rather naturally. Mars appears to be rather small. Uranus and Neptune have rather high densities indicating some loss of gases, probably hydrogen and helium. When we attempt to estimate the mass of primitive solar material from which the planets were evolved, we conclude that they evolved from very similar masses. Later, I shall argue that the process was a very inefficient one.

scholarly journals The Earth's Gold: Where Did It Really Come From?

2018 ◽  
Author(s):  
Elizabeth P. Tito ◽  
Vadim I. Pavlov
Keyword(s):  
Solar System ◽  
Milky Way ◽  
Chemical Elements ◽  
Heavy Elements ◽  
Terrestrial Planets ◽  
The Sun ◽  
Early Solar System ◽  
Reaction Channels

Why is it that in the neighborhood of a calm ordinary star (the Sun) located at the quiet periphery of its galaxy (the Milky Way), non-native heavy elements are abundant in such concentrated form? Where did these elements really come from? Where did Earth's gold come from? Our analysis of the known data offers a fact-reconciling hypothesis: What if, in the early solar system, an explosive collision occurred -- of a traveling from afar giant-nuclear-drop-like object with a local massive dense object (perhaps a then-existent companion of the Sun) -- and the debris, through the multitude of reaction channels and nuclei transformations, was then responsible for (1) the enrichment of the solar system with the cocktail of all detected exogenous chemical elements, and (2) the eventual formation of the terrestrial planets that pre-collision did not exist, thus offering a possible explanation for their inner position and compositional differences within the predominantly hydrogen-helium rest of the solar system.

scholarly journals Aluminum-26 chronology of dust coagulation and early solar system evolution

2019 ◽  
Vol 5 (9) ◽  
pp. eaaw3350 ◽  
Author(s):  
M.-C. Liu ◽  
J. Han ◽  
A. J. Brearley ◽  
A. T. Hertwig
Keyword(s):  
Solar System ◽  
Time Scales ◽  
Time Scale ◽  
Isotopic Analysis ◽  
Class I ◽  
Terrestrial Planets ◽  
The Sun ◽  
Early Solar System ◽  
System Evolution ◽  
Time Gap

Dust condensation and coagulation in the early solar system are the first steps toward forming the terrestrial planets, but the time scales of these processes remain poorly constrained. Through isotopic analysis of small Ca-Al–rich inclusions (CAIs) (30 to 100 μm in size) found in one of the most pristine chondrites, Allan Hills A77307 (CO3.0), for the short-lived 26Al-26Mg [t1/2 = 0.72 million years (Ma)] system, we have identified two main populations of samples characterized by well-defined 26Al/27Al = 5.40 (±0.13) × 10−5 and 4.89 (±0.10) × 10−5. The result of the first population suggests a 50,000-year time scale between the condensation of micrometer-sized dust and formation of inclusions tens of micrometers in size. The 100,000-year time gap calculated from the above two 26Al/27Al ratios could also represent the duration for the Sun being a class I source.

scholarly journals Isotopic evidence for primordial molecular cloud material in metal-rich carbonaceous chondrites

2016 ◽  
Vol 113 (8) ◽  
pp. 2011-2016 ◽  
Author(s):  
Elishevah M. M. E. Van Kooten ◽  
Daniel Wielandt ◽  
Martin Schiller ◽  
Kazuhide Nagashima ◽  
Aurélien Thomen ◽  
...  
Keyword(s):  
Solar System ◽  
Thermal Processing ◽  
Molecular Cloud ◽  
Decay Product ◽  
Isotopic Signature ◽  
Carbonaceous Chondrites ◽  
Outer Solar System ◽  
Precursor Material ◽  
System Composition ◽  
Cloud Material

The short-lived 26Al radionuclide is thought to have been admixed into the initially 26Al-poor protosolar molecular cloud before or contemporaneously with its collapse. Bulk inner Solar System reservoirs record positively correlated variability in mass-independent 54Cr and 26Mg*, the decay product of 26Al. This correlation is interpreted as reflecting progressive thermal processing of in-falling 26Al-rich molecular cloud material in the inner Solar System. The thermally unprocessed molecular cloud matter reflecting the nucleosynthetic makeup of the molecular cloud before the last addition of stellar-derived 26Al has not been identified yet but may be preserved in planetesimals that accreted in the outer Solar System. We show that metal-rich carbonaceous chondrites and their components have a unique isotopic signature extending from an inner Solar System composition toward a 26Mg*-depleted and 54Cr-enriched component. This composition is consistent with that expected for thermally unprocessed primordial molecular cloud material before its pollution by stellar-derived 26Al. The 26Mg* and 54Cr compositions of bulk metal-rich chondrites require significant amounts (25–50%) of primordial molecular cloud matter in their precursor material. Given that such high fractions of primordial molecular cloud material are expected to survive only in the outer Solar System, we infer that, similarly to cometary bodies, metal-rich carbonaceous chondrites are samples of planetesimals that accreted beyond the orbits of the gas giants. The lack of evidence for this material in other chondrite groups requires isolation from the outer Solar System, possibly by the opening of disk gaps from the early formation of gas giants.

scholarly journals Iron isotope evidence for very rapid accretion and differentiation of the proto-Earth

2020 ◽  
Vol 6 (7) ◽  
pp. eaay7604 ◽  
Author(s):  
Martin Schiller ◽  
Martin Bizzarro ◽  
Julien Siebert
Keyword(s):  
Solar System ◽  
Isotope Composition ◽  
Terrestrial Planets ◽  
Carbonaceous Chondrites ◽  
Iron Isotope ◽  
System Composition ◽  
Solar System Objects ◽  
History Of ◽  
Isotope Evidence ◽  
Enstatite Chondrites

Nucleosynthetic isotope variability among solar system objects provides insights into the accretion history of terrestrial planets. We report on the nucleosynthetic Fe isotope composition (μ54Fe) of various meteorites and show that the only material matching the terrestrial composition is CI (Ivuna-type) carbonaceous chondrites, which represent the bulk solar system composition. All other meteorites, including carbonaceous, ordinary, and enstatite chondrites, record excesses in μ54Fe. This observation is inconsistent with protracted growth of Earth by stochastic collisional accretion, which predicts a μ54Fe value reflecting a mixture of the various meteorite parent bodies. Instead, our results suggest a rapid accretion and differentiation of Earth during the ~5–million year disk lifetime, when the volatile-rich CI-like material is accreted to the proto-Sun via the inner disk.

The thallium isotope composition of carbonaceous chondrites — New evidence for live 205Pb in the early solar system

2010 ◽  
Vol 291 (1-4) ◽  
pp. 39-47 ◽  
Author(s):  
R.G.A. Baker ◽  
M. Schönbächler ◽  
M. Rehkämper ◽  
H.M. Williams ◽  
A.N. Halliday
Keyword(s):  
Solar System ◽  
Isotope Composition ◽  
Carbonaceous Chondrites ◽  
Early Solar System ◽  
New Evidence

The early Solar System and the rotation of the Sun

1984 ◽  
Vol 313 (1524) ◽  
pp. 39-45 ◽  
Keyword(s):  
Angular Momentum ◽  
Solar System ◽  
Magnetic Coupling ◽  
Central Star ◽  
The Sun ◽  
Early Solar System ◽  
Low Mass Stars ◽  
Hydrogen Burning ◽  
Low Mass ◽  
Solid Bodies

In most discussions of the formation of the Solar System, the early Sun is assumed to have possessed the bulk of the angular momentum of the system, and a closely surrounding disc of gas was spun out, which, through magnetic coupling, acquired a progressively larger proportion of the total angular momentum. There are difficulties with this model in accounting for the inclined axis of the Sun, the magnitude of the magnetic coupling required, and the nucleogenetic variations recently observed in the Solar System. Another possibility exists, namely that of a slowly contracting disc of interstellar material, leading to the formation of both a central star and a protoplanetary disc. In this model one can better account for the tilt of the Sun’s axis and the lack of mixing necessary to account for the nucleogenetic evidence. The low angular momentum of the Sun and of other low mass stars is then seen as resulting from a slow build-up as a degenerate dwarf, acquiring orbital material at a low specific angular momentum. When the internal temperature reaches the threshold for hydrogen burning, the star expands to the Main Sequence and is now a slow rotator. More massive stars would spin quickly because they had to acquire orbiting material after the expansion, and therefore at a high specific angular momentum. A process of gradual inward spiralling may also allow materials derived from different sources to accumulate into solid bodies, and be placed on a great variety of orbits in the outer reaches of the system, setting up the cometary cloud of uneven nucleogenetic composition.

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