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 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.

Molecular Cloud Origin for Oxygen Isotopic Heterogeneity Recorded by a Primordial Spinel-rich Refractory Inclusion

2019 ◽  
Vol 884 (2) ◽  
pp. L29
Author(s):  
Justin I. Simon ◽  
D. Kent Ross ◽  
Ann N. Nguyen ◽  
Steven B. Simon ◽  
Scott Messenger
Keyword(s):  
Molecular Cloud ◽  
Isotopic Heterogeneity ◽  
Oxygen Isotopic ◽  
Refractory Inclusion

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 Oxygen isotopic heterogeneity of Pali Aike basaltic magmas from southern Patagonia as evidenced by oxygen isotope compositions of olivines

2015 ◽  
Vol 49 (1) ◽  
pp. 83-101
Author(s):  
Mi Kyung Choo ◽  
Kyu Han Kim ◽  
Jong Ik Lee ◽  
Mi Jung Lee ◽  
Sung Hi Choi ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Isotopic Heterogeneity ◽  
Southern Patagonia ◽  
Basaltic Magmas ◽  
Oxygen Isotopic

Isotopic variations in primitive meteorites

1981 ◽  
Vol 303 (1477) ◽  
pp. 339-349 ◽  
Keyword(s):  
Solar System ◽  
Time Scale ◽  
Decay Product ◽  
Common Source ◽  
Time Interval ◽  
Crystal Formation ◽  
Ordinary Chondrites ◽  
Gas Reservoir ◽  
Oxygen Isotopic ◽  
Isotopic Variations

Oxygen isotopic variations in carbonaceous chondrites and in ordinary chondrites can each be interpreted as mixtures of two isotopically different reservoirs, one consisting of solids, enriched in 16 O , the other of a gas, depleted in 16 O relative to terrestrial abundances. The data suggest a common source of the solids for each of the two classes of meteorites, but a different gas reservoir for each. These conditions might prevail in gaseous protoplanets. Radiogenic 26 Mg is variable in abundance among some classes of Allende inclusions, implying either nebular heterogeneity with respect to 26 A1/ 27 Al ratios, or time differences of crystal formation of 1 or 2 x 10 6 a. The presence of excess 107 Ag from decay of extinct 107 Pd supports the evidence from 26 Mg for a time interval of at most a few million years between the last nucleosynthetic event and accretion of substantial bodies in the Solar System. The widespread small excess of 50 Ti in Allende inclusions is tantalizing, but unexplained. An exceptional hibonite-rich inclusion from Allende contains strongly fractionated isotopes of oxygen and calcium, but isotopically normal magnesium. Its trace elements imply association with a hot, oxidized gas. Among the volatile elements, neon-E has been shown to be essentially pure 22 Ne, and appears to be the decay product of extinct 22 Na. If so, condensation of some stellar ejecta must take place on a time scale of a year or so. The problem of reconciling the 26 A1 time scale of about 10 6 years between nucleosynthesis and Solar System condensation with the 10 8 year scale implied by the decay of 129 I to 129 Xe and fission of 244 Pu requires that at most a small fraction of the 129 I and 244 Pu be formed in the most recent event. Progress has been made in establishing the carrier phases of isotopically anomalous xenon and krypton. The apparent location of anomalous xenon and 14 N-rich nitrogen in identical carriers supports the notion that nucleosynthetic anomalies in nitrogen are also present in Allende.

scholarly journals Stable strontium isotopic heterogeneity in the solar system from double-spike data

2017 ◽  
pp. 35-40 ◽  
Author(s):  
B.L.A. Charlier ◽  
I.J. Parkinson ◽  
K.W. Burton ◽  
M.M. Grady ◽  
C.J.N. Wilson ◽  
...  
Keyword(s):  
Solar System ◽  
Isotopic Heterogeneity ◽  
Stable Strontium

scholarly journals Multiple generations of grain aggregation in different environments preceded solar system body formation

2018 ◽  
Vol 115 (26) ◽  
pp. 6608-6613 ◽  
Author(s):  
Hope A. Ishii ◽  
John P. Bradley ◽  
Hans A. Bechtel ◽  
Donald E. Brownlee ◽  
Karen C. Bustillo ◽  
...  
Keyword(s):  
Solar System ◽  
Organic Carbon ◽  
Molecular Cloud ◽  
Interstellar Dust ◽  
Solar Nebula ◽  
Carbon Matrix ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
System Body

The solar system formed from interstellar dust and gas in a molecular cloud. Astronomical observations show that typical interstellar dust consists of amorphous (a-) silicate and organic carbon. Bona fide physical samples for laboratory studies would yield unprecedented insight about solar system formation, but they were largely destroyed. The most likely repositories of surviving presolar dust are the least altered extraterrestrial materials, interplanetary dust particles (IDPs) with probable cometary origins. Cometary IDPs contain abundant submicrona-silicate grains called GEMS (glass with embedded metal and sulfides), believed to be carbon-free. Some have detectable isotopically anomalousa-silicate components from other stars, proving they are preserved dust inherited from the interstellar medium. However, it is debated whether the majority of GEMS predate the solar system or formed in the solar nebula by condensation of high-temperature (>1,300 K) gas. Here, we map IDP compositions with single nanometer-scale resolution and find that GEMS contain organic carbon. Mapping reveals two generations of grain aggregation, the key process in growth from dust grains to planetesimals, mediated by carbon. GEMS grains, some witha-silicate subgrains mantled by organic carbon, comprise the earliest generation of aggregates. These aggregates (and other grains) are encapsulated in lower-density organic carbon matrix, indicating a second generation of aggregation. Since this organic carbon thermally decomposes above ∼450 K, GEMS cannot have accreted in the hot solar nebula, and formed, instead, in the cold presolar molecular cloud and/or outer protoplanetary disk. We suggest that GEMS are consistent with surviving interstellar dust, condensed in situ, and cycled through multiple molecular clouds.

scholarly journals Comments

1990 ◽  
Vol 123 ◽  
pp. 417-419
Author(s):  
Fred Hoyle
Keyword(s):  
Magnetic Field ◽  
Solar System ◽  
Molecular Cloud ◽  
The Sun ◽  
Ultimate Explanation ◽  
Word Origin ◽  
Entire Universe ◽  
A Chain ◽  
The Magnetic Field

The word 'origin' is one of the most widely used in science. Yet it seems to me to be always used either improperly or ineffectively. Ineffective uses have a derivative quality about them. As an example, suppose we ask: What was the 'origin' of the magnetic field of the Sun? The best answer I suppose is that the magnetic field of the Sun was formed by the compression of a magnetic field that was present already in the gases of the molecular cloud in which the Sun and Solar System were formed some 4.5 X 109 years ago. But what then was the 'origin' of the field in the molecular cloud? It was present already in the gases from which our galaxy was formed, one might suggest. A further displacement then takes us to the manner of 'origin' of t he entire universe, so that no ultimate explanation has really been given. The problem has only been displaced along a chain until it passes into a mental fog through which some claim to see clearly but through which others, including myself, do not see at all.

Recent developments on the problem of the origin of the Solar System

1981 ◽  
Vol 303 (1477) ◽  
pp. 369-375 ◽  
Keyword(s):  
Solar System ◽  
Molecular Cloud ◽  
Recent Developments ◽  
Isotopic Anomalies

Relics of the molecular cloud origins of the Solar System are found in the deuterated molecules of meteorites. The situation is summarized and discussed in conjunction with the isotopic anomalies of heavier elements, to obtain an overall view of the whole event.

Sign in / Sign up

Export Citation Format

Share Document