scholarly journals Early scattering of the solar protoplanetary disk recorded in meteoritic chondrules

2016 ◽  
Vol 2 (7) ◽  
pp. e1601001 ◽  
Author(s):  
Yves Marrocchi ◽  
Marc Chaussidon ◽  
Laurette Piani ◽  
Guy Libourel

Meteoritic chondrules are submillimeter spherules representing the major constituent of nondifferentiated planetesimals formed in the solar protoplanetary disk. The link between the dynamics of the disk and the origin of chondrules remains enigmatic. Collisions between planetesimals formed at different heliocentric distances were frequent early in the evolution of the disk. We show that the presence, in some chondrules, of previously unrecognized magnetites of magmatic origin implies the formation of these chondrules under impact-generated oxidizing conditions. The three oxygen isotopes systematic of magmatic magnetites and silicates can only be explained by invoking an impact between silicate-rich and ice-rich planetesimals. This suggests that these peculiar chondrules are by-products of the early mixing in the disk of populations of planetesimals from the inner and outer solar system.

2020 ◽  
Vol 117 (38) ◽  
pp. 23426-23435 ◽  
Author(s):  
Curtis D. Williams ◽  
Matthew E. Sanborn ◽  
Céline Defouilloy ◽  
Qing-Zhu Yin ◽  
Noriko T. Kita ◽  
...  

Dynamic models of the protoplanetary disk indicate there should be large-scale material transport in and out of the inner Solar System, but direct evidence for such transport is scarce. Here we show that the ε50Ti-ε54Cr-Δ17O systematics of large individual chondrules, which typically formed 2 to 3 My after the formation of the first solids in the Solar System, indicate certain meteorites (CV and CK chondrites) that formed in the outer Solar System accreted an assortment of both inner and outer Solar System materials, as well as material previously unidentified through the analysis of bulk meteorites. Mixing with primordial refractory components reveals a “missing reservoir” that bridges the gap between inner and outer Solar System materials. We also observe chondrules with positive ε50Ti and ε54Cr plot with a constant offset below the primitive chondrule mineral line (PCM), indicating that they are on the slope ∼1.0 in the oxygen three-isotope diagram. In contrast, chondrules with negative ε50Ti and ε54Cr increasingly deviate above from PCM line with increasing δ18O, suggesting that they are on a mixing trend with an ordinary chondrite-like isotope reservoir. Furthermore, the Δ17O-Mg# systematics of these chondrules indicate they formed in environments characterized by distinct abundances of dust and H2O ice. We posit that large-scale outward transport of nominally inner Solar System materials most likely occurred along the midplane associated with a viscously evolving disk and that CV and CK chondrules formed in local regions of enhanced gas pressure and dust density created by the formation of Jupiter.


Science ◽  
2021 ◽  
Vol 371 (6527) ◽  
pp. 365-370
Author(s):  
Tim Lichtenberg ◽  
Joanna Dra̧żkowska ◽  
Maria Schönbächler ◽  
Gregor J. Golabek ◽  
Thomas O. Hands

Geochemical and astronomical evidence demonstrates that planet formation occurred in two spatially and temporally separated reservoirs. The origin of this dichotomy is unknown. We use numerical models to investigate how the evolution of the solar protoplanetary disk influenced the timing of protoplanet formation and their internal evolution. Migration of the water snow line can generate two distinct bursts of planetesimal formation that sample different source regions. These reservoirs evolve in divergent geophysical modes and develop distinct volatile contents, consistent with constraints from accretion chronology, thermochemistry, and the mass divergence of inner and outer Solar System. Our simulations suggest that the compositional fractionation and isotopic dichotomy of the Solar System was initiated by the interplay between disk dynamics, heterogeneous accretion, and internal evolution of forming protoplanets.


1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.


1997 ◽  
Author(s):  
R. Lewis ◽  
G. Smith ◽  
B. Dundore ◽  
J. Fulmer ◽  
S. Chakrabarti ◽  
...  

2013 ◽  
Vol 14 (4) ◽  
pp. 393-398

The occurrence of trihalomethanes (THMs) was studied in the drinking water samples from urban water supply network of Karachi city that served more than 18 million people. Drinking water samples were collected from 58 locations in summer (May-August) and winter (November-February) seasons. The major constituent of THMs detected was chloroform in winter (92.34%) and summer (93.07%), while the other THMs determined at lower concentrations. Summer and winter concentrations of total THMs at places exceed the levels regulated by UEPA (80 μg l-1) and WHO (100 μg l-1). GIS linked temporal variability in two seasons showed significantly higher median concentration (2.5%-23.06%) of THMs compared to winter.


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