scholarly journals Short-Lived Nuclei in the Early Solar System: A Low Mass Stellar Source?

2003 ◽  
Vol 20 (4) ◽  
pp. 356-370 ◽  
Author(s):  
M. Busso ◽  
R. Gallino ◽  
G. J. Wasserburg
Keyword(s):  
Solar System ◽  
Asymptotic Giant Branch ◽  
Early Solar System ◽  
Uncertainty Range ◽  
System A ◽  
Free Decay ◽  
Low Mass ◽  
Stellar Source ◽  
Review Current

AbstractWe discuss possible stellar origins of short-lived radioactive nuclei with meanlife τ ≤ 100 Myr, which were shown to be alive in the Early Solar System (ESS). We first review current ideas on the production of nuclides having 10 ≤ τ ≤ 100 Myr, which presumably derive from the continuous interplay of galactic astration, nucleosynthesis from massive supernovae and free decay in the interstellar medium. The abundance of the shorter lived 53Mn might be explained by this same scenario. Then we consider the nuclei 107Pd, 26Al, 41Ca and 60Fe, whose early solar system abundances are too high to have originated in this way. Present evidence favours a stellar origin, particularly for 107Pd, 26Al and 60Fe, rather than an in situ production by energetic solar particles. The idea of an encounter (rather close in time and space) between the forming Sun and a dying star is therefore discussed: this star may or may not have also triggered the solar formation. Recent nucleosynthesis calculations for the yields of the relevant short-lived isotopes and of their stable reference nuclei are discussed. Massive stars evolving to type II supernovae (either leaving a neutron star or a black hole as a remnant) seem incapable of explaining the four most critical ESS radioactivities in their observed abundance ratios. An asymptotic giant branch (AGB) star seems to be a viable source, especially if of relatively low initial mass (M ≤ 3 M⊙) and with low neutron exposure: this model can provide a solution for 26Al, 41Ca and 107Pd, with important contributions to 60Fe, which are inside the present uncertainty range of the 60Fe early solar system abundance. Such a model requires that 26Al is produced substantially on the AGB by cool bottom processing. The remaining inventory of short-lived species in the solar nebula would then be attributed to the continuous galactic processing, with the exception of 10Be, which must reflect production by later proton bombardment at a low level during early solar history.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

scholarly journals In-Situ Exploration of Dust in the Solar System and Initial Results from the Galileo Dust Detector

1991 ◽  
Vol 126 ◽  
pp. 21-28
Author(s):  
E. Grün ◽  
H. Fechtig ◽  
M. S. Hanner ◽  
J. Kissel ◽  
B.-A. Lindblad ◽  
...  
Keyword(s):  
Solar System ◽  
Impact Ionization ◽  
Interplanetary Space ◽  
Interplanetary Dust ◽  
High Mass ◽  
Large Area ◽  
Dust Flux ◽  
Highly Sensitive ◽  
Low Mass

AbstractIn-situ measurements of interplanetary dust have been performed in the heliocentric distance range from 0.3 AU out to 18 AU. Due to their small sensitive areas (typically 0.01 m2for the highly sensitive impact ionization sensors) or low mass sensitivities (≥10−9g of the large area penetration detectors) previous instruments recorded only a few 100 impacts during their lifetimes. Nevertheless, important information on the distribution of dust in interplanetary space has been obtained between 0.3 and 18 AU distance from the Sun. The Galileo dust detector combines the high mass sensitivity of impact ionization detectors (10−15g) together with a large sensitive area (0.1 m2). The Galileo spacecraft was launched on October 18, 1989 and is on its solar system cruise towards Jupiter. Initial measurements of the dust flux from 0.7 to 1.2 AU are presented.

scholarly journals The chemical connection between 67P/C-G and IRAS 16293-2422

2017 ◽  
Vol 13 (S332) ◽  
pp. 196-201
Author(s):  
Maria Nikolayevna Drozdovskaya ◽  
Ewine F. van Dishoeck ◽  
Martin Rubin ◽  
Jes Kristian Jørgensen ◽  
Kathrin Altwegg
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
Chemical Evolution ◽  
Protoplanetary Disks ◽  
In Situ Measurements ◽  
Isotopic Ratios ◽  
Data Sets ◽  
Low Mass ◽  
Comet 67P

AbstractThe chemical evolution of a star- and planet-forming system begins in the prestellar phase and proceeds across the subsequent evolutionary phases. The chemical trail from cores to protoplanetary disks to planetary embryos can be studied by comparing distant young protostars and comets in our Solar System. One particularly chemically rich system that is thought to be analogous to our own is the low-mass IRAS 16293-2422. ALMA-PILS observations have made the study of chemistry on the disk scales (<100 AU) of this system possible. Under the assumption that comets are pristine tracers of the outer parts of the innate protosolar disk, it is possible to compare the composition of our infant Solar System to that of IRAS 16293-2422. The Rosetta mission has yielded a wealth of unique in situ measurements on comet 67P/C-G, making it the best probe to date. Herein, the initial comparisons in terms of the chemical composition and isotopic ratios are summarized. Much work is still to be carried out in the future as the analysis of both of these data sets is still ongoing.

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.

scholarly journals Neutron-captures in Low Mass Stars and the Early Solar System Record of Short-lived Radioactivities

2017 ◽  
Vol 165 ◽  
pp. 02003
Author(s):  
Maurizio Busso ◽  
Diego Vescovi ◽  
Oscar Trippella ◽  
Sara Palmerini ◽  
Sergio Cristallo ◽  
...  
Keyword(s):  
Solar System ◽  
Early Solar System ◽  
Low Mass Stars ◽  
Low Mass

scholarly journals Circumstellar disks in high-mass star environments: the early solar system

2009 ◽  
Vol 5 (H15) ◽  
pp. 746-747
Author(s):  
Thierry Montmerle ◽  
Matthieu Gounelle ◽  
Georges Meynet
Keyword(s):  
Solar System ◽  
Circumstellar Disks ◽  
Energetic Particles ◽  
High Mass ◽  
Circumstellar Disk ◽  
Mass Star ◽  
Early Solar System ◽  
Explosive Nucleosynthesis ◽  
By Products

AbstractThe early solar system represents the only case we have of a circumstellar disk that can be investigated “in situ” -albeit 4.6 Gyr after its formation. Meteorites studies give mounting evidence for an intense irradiation phase of the young circumsolar disk by energetic particles, and also for contamination by products of high-mass stellar and/or explosive nucleosynthesis. We thus discuss the conditions of the birth of the solar system in a high-mass star environment.

scholarly journals Stellar origin of the 182Hf cosmochronometer and the presolar history of solar system matter

Science ◽  
2014 ◽  
Vol 345 (6197) ◽  
pp. 650-653 ◽  
Author(s):  
Maria Lugaro ◽  
Alexander Heger ◽  
Dean Osrin ◽  
Stephane Goriely ◽  
Kai Zuber ◽  
...  
Keyword(s):  
Solar System ◽  
Neutron Capture ◽  
Half Life ◽  
Slow Neutron ◽  
Asymptotic Giant Branch ◽  
Asymptotic Giant Branch Stars ◽  
Early Solar System ◽  
Capture Process ◽  
History Of ◽  
Giant Branch Stars

Among the short-lived radioactive nuclei inferred to be present in the early solar system via meteoritic analyses, there are several heavier than iron whose stellar origin has been poorly understood. In particular, the abundances inferred for 182Hf (half-life = 8.9 million years) and 129I (half-life = 15.7 million years) are in disagreement with each other if both nuclei are produced by the rapid neutron-capture process. Here, we demonstrate that contrary to previous assumption, the slow neutron-capture process in asymptotic giant branch stars produces 182Hf. This has allowed us to date the last rapid and slow neutron-capture events that contaminated the solar system material at ∼100 million years and ∼30 million years, respectively, before the formation of the Sun.

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