scholarly journals Asteroid 6 Hebe: The probable parent body of the H-type ordinary chondrites and the IIE iron meteorites

1998 ◽  
Vol 33 (6) ◽  
pp. 1281-1295 ◽  
Author(s):  
Michael J. GAFFEY ◽  
Sarah L. GILBERT
Keyword(s):  
Parent Body ◽  
Ordinary Chondrites ◽  
Iron Meteorites

scholarly journals Widely distributed exogenic materials of varying compositions and morphologies on asteroid (101955) Bennu

2021 ◽  
Author(s):  
Eri Tatsumi ◽  
Marcel Popescu ◽  
Humberto Campins ◽  
Julia de León ◽  
Juan Luis Rizos García ◽  
...  
Keyword(s):  
Near Infrared ◽  
Principal Component ◽  
Parent Body ◽  
Ordinary Chondrites ◽  
Near Infrared Reflectance ◽  
Spatially Resolved ◽  
Average Spectrum ◽  
Band Absorption ◽  
Rich Material ◽  
The One

Abstract Using the multiband imager MapCam onboard the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) spacecraft, we identified 77 instances of proposed exogenic materials distributed globally on the surface of the B-type asteroid (101955) Bennu. We identified materials as exogenic on the basis of an absorption near 1 µm that is indicative of anhydrous silicates. The exogenic materials are spatially resolved by the telescopic camera PolyCam. All such materials are brighter than their surroundings, and they are expressed in a variety of morphologies: homogeneous, breccia-like, inclusion-like, and others. Inclusion-like features are the most common. Visible spectrophotometry was obtained for 46 of the 77 locations from MapCam images. Principal component analysis indicates at least two trends: (i) mixing of Bennu's average spectrum with a strong 1-µm band absorption, possibly from pyroxene-rich material, and (ii) mixing with a weak 1-µm band absorption. The endmember with a strong 1-µm feature is consistent with Howardite-Eucrite-Diogenite (HED) meteorites, whereas the one showing a weak 1-µm feature may be consistent with HEDs, ordinary chondrites, or carbonaceous chondrites. The variation in the few available near-infrared reflectance spectra strongly suggests varying compositions among the exogenic materials. Thus, Bennu might record the remnants of multiple impacts with different compositions to its parent body, which could have happened in the very early history of the Solar System. Moreover, at least one of the exogenic objects is compositionally different from the exogenic materials found on the similar asteroid (162173) Ryugu, and they suggest different impact tracks.

scholarly journals 4. Parent Bodies of Iron Meteorites

1977 ◽  
Vol 39 ◽  
pp. 439-444
Author(s):  
E. R. D. Scott
Keyword(s):  
Mineralogical Composition ◽  
Parent Body ◽  
Iron Meteorites ◽  
Chemical And Mineralogical Composition

On the basis of their chemical and mineralogical composition, 420 iron meteorites have been classified into 12 different groups. Each group seems to have come from a separate parent body. The largest group, IIIAB, probably formed an asteroidal core in a body approximately 100 km in radius, which was largely destroyed by collision 630 My ago. Another 67 analyzed irons do not belong to these groups, and may represent samples from another 20 or more bodies.

scholarly journals Meteorite evidence for partial differentiation and protracted accretion of planetesimals

2020 ◽  
Vol 6 (30) ◽  
pp. eaba1303
Author(s):  
Clara Maurel ◽  
James F. J. Bryson ◽  
Richard J. Lyons ◽  
Matthew R. Ball ◽  
Rajesh V. Chopdekar ◽  
...  
Keyword(s):  
Parent Body ◽  
Thermal Impact ◽  
Iron Meteorites ◽  
Planetary Body ◽  
Classification Schemes ◽  
Partial Differentiation ◽  
Internal Structures ◽  
Natural Outcome ◽  
Collisional Evolution

Modern meteorite classification schemes assume that no single planetary body could be source of both unmelted (chondritic) and melted (achondritic) meteorites. This dichotomy is a natural outcome of formation models assuming that planetesimal accretion occurred nearly instantaneously. However, it has recently been proposed that the accretion of many planetesimals lasted over ≳1 million years (Ma). This could have resulted in partially differentiated internal structures, with individual bodies containing iron cores, achondritic silicate mantles, and chondritic crusts. This proposal can be tested by searching for a meteorite group containing evidence for these three layers. We combine synchrotron paleomagnetic analyses with thermal, impact, and collisional evolution models to show that the parent body of the enigmatic IIE iron meteorites was such a partially differentiated planetesimal. This implies that some chondrites and achondrites simultaneously coexisted on the same planetesimal, indicating that accretion was protracted and that apparently undifferentiated asteroids may contain melted interiors.

scholarly journals Fe-Ni-P-S Melt Pockets in Elga IIE Iron Meteorite: Evidence for the Origin at High-Pressures Up to 20 GPa

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 616 ◽  
Author(s):  
Konstantin Litasov ◽  
Svetlana Teplyakova ◽  
Anton Shatskiy ◽  
Konstantin Kuper
Keyword(s):  
Experimental Data ◽  
Solid Solution ◽  
Important Implication ◽  
High Pressures ◽  
Bulk Composition ◽  
Parent Body ◽  
Iron Meteorite ◽  
Iron Meteorites ◽  
High Pressures And Temperatures ◽  
Melt Pockets

Here we report new data on high-pressure microstructures in Elga group IIE iron meteorites, made of solidified Fe-Ni-P-S melt pockets and microcrystalline aggregates, which could be formed only at high pressures and temperatures according to the experimental data. The bulk composition of the melt pockets and crystals correspond to the Fe3P-Fe3S solid solution with the closure of an immiscibility gap at pressures near 20 GPa in static experiments. Some other melt pockets fit with the Fe2S-Fe2P compositions, which could also correspond to high pressures and temperatures. The results suggest a late shock episode during the formation of the IIE iron parent body, which may be prior or due to the final disruption that caused the meteorite arrival to Earth. It also has an important implication to the shock features in other meteorites, such as ureilite.

Origin of Iron Meteorite Groups IAB and IIICD

1980 ◽  
Vol 35 (8) ◽  
pp. 781-795 ◽  
Author(s):  
John T. Wasson ◽  
John Willis ◽  
Chien M. Wai ◽  
Alfred Kracher
Keyword(s):  
Parent Body ◽  
Iron Meteorite ◽  
Iron Meteorites ◽  
Impact Melt ◽  
Equilibrium Crystallization ◽  
Ni Content ◽  
Oxide Phases ◽  
Host Metal ◽  
Impact Melts ◽  
The Impact

AbstractSeveral low-Ni iron meteorites previously assigned to group IAB are reclassified IIICD on the basis of lower Ge, Ga, W and Ir concentrations and higher As concentrations; the low-Ni extreme of IIICD is now 62 mg/g, that of IAB is 64 mg/g. The resulting fractionation patterns in the two groups are quite similar. It has long been established that, in contrast to the magmatic iron meteorite groups, IAB and IIICD did not form by fractional crystallization of a metallic magma. Other models have been proposed, but all have serious flaws. A new model is proposed involving the formation of each iron in small pools of impact melt on a parent body consisting of material similar to the chondritic inclusions found in some IAB and IIICD irons, but initially unequilibrated. These impact melts ranged in temperatures from ~ 1190 K to ~ 1350 K. The degree of equilibration between melt and unmelted solids ranged from minimal at the lowest temperature to moderate at the highest temperature. The lowest temperature melts were near the cotectic in the Fe-Ni-S system with Ni contents of ~ 12 atom %. Upon cooling, these precipitated metal having ~ 600 mg/g Ni by equilibrium crystallization. The Ni-rich melt resulted from the melting of Ni-rich sulfides and metal in the unequilibrated chondritic parent. Low-Ni irons formed in high temperature melts near the composition of the FeS-Fe eutectic or somewhat more metal rich. We suggest that the decreasing Ge, Ga and refractory abundances with increasing Ni concentration reflect the trapping of these elements in oxide phases in the unequilibrated chondritic material, and that very little entered the Ni-rich melt parental to the Oktibbeha County iron. The remaining elements tended to have element/Ni ratios in the melts that were more or less independent of temperature. The remarkable correlation between I-Xe age of the chondritic inclusions and Ni content of the host metal is explained by a detailed evolution of (mega)regolith in which these groups originated. The most Ni-rich melts could only be generated from an unequilibrated chondrite parent; as the continuing deposition of impact energy produced increasingly higher grades of metamorphism, the maximum Ni content of the impact melts (and their subsequently precipitated metal) gradually decreased.

scholarly journals Tungsten isotopic constraints on the age and origin of chondrules

2016 ◽  
Vol 113 (11) ◽  
pp. 2886-2891 ◽  
Author(s):  
Gerrit Budde ◽  
Thorsten Kleine ◽  
Thomas S. Kruijer ◽  
Christoph Burkhardt ◽  
Knut Metzler
Keyword(s):  
Planet Formation ◽  
Solar Nebula ◽  
Carbonaceous Chondrite ◽  
Critical Role ◽  
Parent Body ◽  
Uneven Distribution ◽  
Time Interval ◽  
Ordinary Chondrites ◽  
Chondrule Formation ◽  
Isotopic Constraints

Chondrules may have played a critical role in the earliest stages of planet formation by mediating the accumulation of dust into planetesimals. However, the origin of chondrules and their significance for planetesimal accretion remain enigmatic. Here, we show that chondrules and matrix in the carbonaceous chondrite Allende have complementary 183W anomalies resulting from the uneven distribution of presolar, stellar-derived dust. These data refute an origin of chondrules in protoplanetary collisions and, instead, indicate that chondrules and matrix formed together from a common reservoir of solar nebula dust. Because bulk Allende exhibits no 183W anomaly, chondrules and matrix must have accreted rapidly to their parent body, implying that the majority of chondrules from a given chondrite group formed in a narrow time interval. Based on Hf-W chronometry on Allende chondrules and matrix, this event occurred ∼2 million years after formation of the first solids, about coeval to chondrule formation in ordinary chondrites.

Thermal history and origin of the IVB iron meteorites and their parent body

2010 ◽  
Vol 74 (15) ◽  
pp. 4493-4506 ◽  
Author(s):  
Jijin Yang ◽  
Joseph I. Goldstein ◽  
Joseph R. Michael ◽  
Paul G. Kotula ◽  
Edward R.D. Scott
Keyword(s):  
Thermal History ◽  
Parent Body ◽  
Iron Meteorites

Restriction of parent body heating by metal‐troilite melting: Thermal models for the ordinary chondrites

2014 ◽  
Vol 49 (4) ◽  
pp. 636-651 ◽  
Author(s):  
Eleanor R. Mare ◽  
Andrew G. Tomkins ◽  
Belinda M. Godel
Keyword(s):  
Parent Body ◽  
Ordinary Chondrites ◽  
Thermal Models

scholarly journals The Relationship of Meteoritic Parent Body Thermal Histories and Electromagnetic Heating by a Pre-Main Sequence T Tauri Sun

1971 ◽  
Vol 12 ◽  
pp. 239-245 ◽  
Author(s):  
C.P. Sonett
Keyword(s):  
Main Sequence ◽  
Solar Nebula ◽  
Parent Body ◽  
Convincing Evidence ◽  
Iron Meteorites ◽  
T Tauri ◽  
Diffusion Studies ◽  
Thermal Histories ◽  
Relationship Of ◽  
The Relationship

Convincing evidence exists that meteoritic matter was reheated shortly after the initial condensation of the solar nebula for those meteorites thought to be derived from parent bodies. This evidence takes the form of cooling rates carefully determined from diffusion studies of the migration rate of Ni across kamacite-taenite boundaries in iron meteorites (Fish, Goles, and Anders, 1960; Goldstein and Ogilvie, 1965; Goldstein and Short, 1967; Wood, 1964). The notion that the irons condensed directly from the solar nebula requires that these measurements and the existence of large Widmanstätten figures be explained as a condensation event. This seems rather unlikely and, in any event, requires a far more complex explanation than heating and melting in a parent body.

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