Olivine-dominated asteroids: Mineralogy and origin

Juan A. Sanchez; Vishnu Reddy; Michael S. Kelley; Edward A. Cloutis; William F. Bottke; David Nesvorný; Michael P. Lucas; Paul S. Hardersen; Michael J. Gaffey; Paul A. Abell; Lucille Le Corre

doi:10.1016/j.icarus.2013.10.006

Olivine-dominated asteroids: Mineralogy and origin

Juan A. Sanchez, Vishnu Reddy, Michael S. Kelley, Edward A. Cloutis, William F. Bottke, David Nesvorný, Michael P. Lucas, Paul S. Hardersen, Michael J. Gaffey, Paul A. Abell, Lucille Le Corre

Research output: Contribution to journal › Article › peer-review

55 Scopus citations

Abstract

Olivine-dominated asteroids are a rare type of objects formed either in nebular processes or through magmatic differentiation. The analysis of meteorite samples suggest that at least 100 parent bodies in the main belt experienced partial or complete melting and differentiation before being disrupted. However, only a few olivine-dominated asteroids, representative of the mantle of disrupted differentiated bodies, are known to exist. Due to the paucity of these objects in the main belt their origin and evolution have been a matter of great debate over the years. In this work we present a detailed mineralogical analysis of twelve olivine-dominated asteroids. We have obtained near-infrared (NIR) spectra (0.7-2.4μm) of asteroids (246) Asporina, (289) Nenetta, (446) Aeternitas, (863) Benkoela, (4125) Lew Allen and (4490) Bamberry. Observations were conducted with the Infrared Telescope Facility (IRTF) on Mauna Kea, Hawai'i. This sample was complemented with spectra of six other olivine-dominated asteroids including (354) Eleonora, (984) Gretia, (1951) Lick, (2501) Lohja, (3819) Robinson and (5261) Eureka obtained by previous workers. Within our sample we distinguish two classes, one that we call monomineralic-olivine asteroids, which are those whose spectra only exhibit the 1μm feature, and another referred to as olivine-rich asteroids, whose spectra exhibit the 1μm feature and a weak (Band II depth ~4%) 2μm feature. For the monomineralic-olivine asteroids the olivine chemistry was found to range from ~Fo₄₉ to Fo₇₀, consistent with the values measured for brachinites and R chondrites. In the case of the olivine-rich asteroids we determined their olivine and low-Ca pyroxene abundance using a new set of spectral calibrations derived from the analysis of R chondrites spectra. We found that the olivine abundance for these asteroids varies from 0.68 to 0.93, while the fraction of low-Ca pyroxene to total pyroxene ranges from 0.6 to 0.9. A search for dynamical connections between the olivine-dominated asteroids and asteroid families found no genetic link (of the type core-mantel-crust) between these objects.

Original language	English (US)
Pages (from-to)	288-300
Number of pages	13
Journal	Icarus
Volume	228
DOIs	https://doi.org/10.1016/j.icarus.2013.10.006
State	Published - Jan 15 2014
Externally published	Yes

Keywords

Asteroids
Infrared observations
Meteorites
Spectroscopy

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

Access to Document

10.1016/j.icarus.2013.10.006

Cite this

@article{af2d4798c79745059f46f1889ad72031,

title = "Olivine-dominated asteroids: Mineralogy and origin",

abstract = "Olivine-dominated asteroids are a rare type of objects formed either in nebular processes or through magmatic differentiation. The analysis of meteorite samples suggest that at least 100 parent bodies in the main belt experienced partial or complete melting and differentiation before being disrupted. However, only a few olivine-dominated asteroids, representative of the mantle of disrupted differentiated bodies, are known to exist. Due to the paucity of these objects in the main belt their origin and evolution have been a matter of great debate over the years. In this work we present a detailed mineralogical analysis of twelve olivine-dominated asteroids. We have obtained near-infrared (NIR) spectra (0.7-2.4μm) of asteroids (246) Asporina, (289) Nenetta, (446) Aeternitas, (863) Benkoela, (4125) Lew Allen and (4490) Bamberry. Observations were conducted with the Infrared Telescope Facility (IRTF) on Mauna Kea, Hawai'i. This sample was complemented with spectra of six other olivine-dominated asteroids including (354) Eleonora, (984) Gretia, (1951) Lick, (2501) Lohja, (3819) Robinson and (5261) Eureka obtained by previous workers. Within our sample we distinguish two classes, one that we call monomineralic-olivine asteroids, which are those whose spectra only exhibit the 1μm feature, and another referred to as olivine-rich asteroids, whose spectra exhibit the 1μm feature and a weak (Band II depth ~4%) 2μm feature. For the monomineralic-olivine asteroids the olivine chemistry was found to range from ~Fo49 to Fo70, consistent with the values measured for brachinites and R chondrites. In the case of the olivine-rich asteroids we determined their olivine and low-Ca pyroxene abundance using a new set of spectral calibrations derived from the analysis of R chondrites spectra. We found that the olivine abundance for these asteroids varies from 0.68 to 0.93, while the fraction of low-Ca pyroxene to total pyroxene ranges from 0.6 to 0.9. A search for dynamical connections between the olivine-dominated asteroids and asteroid families found no genetic link (of the type core-mantel-crust) between these objects.",

keywords = "Asteroids, Infrared observations, Meteorites, Spectroscopy",

author = "Sanchez, {Juan A.} and Vishnu Reddy and Kelley, {Michael S.} and Cloutis, {Edward A.} and Bottke, {William F.} and David Nesvorn{\'y} and Lucas, {Michael P.} and Hardersen, {Paul S.} and Gaffey, {Michael J.} and Abell, {Paul A.} and Corre, {Lucille Le}",

note = "Funding Information: This paper is based on data obtained with the Infrared Telescope Facility on Mauna Kea, Hawai{\textquoteright}i. Some of the data used in this work were obtained from the SMASS II and S 3 OS 2 . In addition, part of the data utilized in this publication were obtained and made available by the MIT-UH-IRTF Joint Campaign for NEO Reconnaissance. The IRTF is operated by the University of Hawaii under Cooperative Agreement No. NCC 5-538 with the National Aeronautics and Space Administration, Office of Space Science, Planetary Astronomy Program. The MIT component of this work is supported by NASA Grant 09-NEOO009-0001 , and by the National Science Foundation under Grant Nos. 0506716 and 0907766 . Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of NASA or the National Science Foundation. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This publication also makes use of data products from NEOWISE, which is a project of the Jet Propulsion Laboratory/California Institute of Technology, funded by the Planetary Science Division of the National Aeronautics and Space Administration. The authors thank, John Hinrichs and Paul Lucey for providing us with data for this research. VR and MJG research was supported by NASA 182 NEOO Program Grant NNX12AG12G, and NASA Planetary Geology and Geophysics Grant NNX11AN84G. We thank the IRTF TAC for awarding time to this project, and to the IRTF TOs and MKSS staff for their support. We also thank the anonymous reviewers for their useful comments, which helped to improve the manuscript.",

year = "2014",

month = jan,

day = "15",

doi = "10.1016/j.icarus.2013.10.006",

language = "English (US)",

volume = "228",

pages = "288--300",

journal = "Icarus",

issn = "0019-1035",

publisher = "Academic Press Inc.",

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TY - JOUR

T1 - Olivine-dominated asteroids

T2 - Mineralogy and origin

AU - Sanchez, Juan A.

AU - Reddy, Vishnu

AU - Kelley, Michael S.

AU - Cloutis, Edward A.

AU - Bottke, William F.

AU - Nesvorný, David

AU - Lucas, Michael P.

AU - Hardersen, Paul S.

AU - Gaffey, Michael J.

AU - Abell, Paul A.

AU - Corre, Lucille Le

N1 - Funding Information: This paper is based on data obtained with the Infrared Telescope Facility on Mauna Kea, Hawai’i. Some of the data used in this work were obtained from the SMASS II and S 3 OS 2 . In addition, part of the data utilized in this publication were obtained and made available by the MIT-UH-IRTF Joint Campaign for NEO Reconnaissance. The IRTF is operated by the University of Hawaii under Cooperative Agreement No. NCC 5-538 with the National Aeronautics and Space Administration, Office of Space Science, Planetary Astronomy Program. The MIT component of this work is supported by NASA Grant 09-NEOO009-0001 , and by the National Science Foundation under Grant Nos. 0506716 and 0907766 . Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of NASA or the National Science Foundation. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This publication also makes use of data products from NEOWISE, which is a project of the Jet Propulsion Laboratory/California Institute of Technology, funded by the Planetary Science Division of the National Aeronautics and Space Administration. The authors thank, John Hinrichs and Paul Lucey for providing us with data for this research. VR and MJG research was supported by NASA 182 NEOO Program Grant NNX12AG12G, and NASA Planetary Geology and Geophysics Grant NNX11AN84G. We thank the IRTF TAC for awarding time to this project, and to the IRTF TOs and MKSS staff for their support. We also thank the anonymous reviewers for their useful comments, which helped to improve the manuscript.

PY - 2014/1/15

Y1 - 2014/1/15

N2 - Olivine-dominated asteroids are a rare type of objects formed either in nebular processes or through magmatic differentiation. The analysis of meteorite samples suggest that at least 100 parent bodies in the main belt experienced partial or complete melting and differentiation before being disrupted. However, only a few olivine-dominated asteroids, representative of the mantle of disrupted differentiated bodies, are known to exist. Due to the paucity of these objects in the main belt their origin and evolution have been a matter of great debate over the years. In this work we present a detailed mineralogical analysis of twelve olivine-dominated asteroids. We have obtained near-infrared (NIR) spectra (0.7-2.4μm) of asteroids (246) Asporina, (289) Nenetta, (446) Aeternitas, (863) Benkoela, (4125) Lew Allen and (4490) Bamberry. Observations were conducted with the Infrared Telescope Facility (IRTF) on Mauna Kea, Hawai'i. This sample was complemented with spectra of six other olivine-dominated asteroids including (354) Eleonora, (984) Gretia, (1951) Lick, (2501) Lohja, (3819) Robinson and (5261) Eureka obtained by previous workers. Within our sample we distinguish two classes, one that we call monomineralic-olivine asteroids, which are those whose spectra only exhibit the 1μm feature, and another referred to as olivine-rich asteroids, whose spectra exhibit the 1μm feature and a weak (Band II depth ~4%) 2μm feature. For the monomineralic-olivine asteroids the olivine chemistry was found to range from ~Fo49 to Fo70, consistent with the values measured for brachinites and R chondrites. In the case of the olivine-rich asteroids we determined their olivine and low-Ca pyroxene abundance using a new set of spectral calibrations derived from the analysis of R chondrites spectra. We found that the olivine abundance for these asteroids varies from 0.68 to 0.93, while the fraction of low-Ca pyroxene to total pyroxene ranges from 0.6 to 0.9. A search for dynamical connections between the olivine-dominated asteroids and asteroid families found no genetic link (of the type core-mantel-crust) between these objects.

AB - Olivine-dominated asteroids are a rare type of objects formed either in nebular processes or through magmatic differentiation. The analysis of meteorite samples suggest that at least 100 parent bodies in the main belt experienced partial or complete melting and differentiation before being disrupted. However, only a few olivine-dominated asteroids, representative of the mantle of disrupted differentiated bodies, are known to exist. Due to the paucity of these objects in the main belt their origin and evolution have been a matter of great debate over the years. In this work we present a detailed mineralogical analysis of twelve olivine-dominated asteroids. We have obtained near-infrared (NIR) spectra (0.7-2.4μm) of asteroids (246) Asporina, (289) Nenetta, (446) Aeternitas, (863) Benkoela, (4125) Lew Allen and (4490) Bamberry. Observations were conducted with the Infrared Telescope Facility (IRTF) on Mauna Kea, Hawai'i. This sample was complemented with spectra of six other olivine-dominated asteroids including (354) Eleonora, (984) Gretia, (1951) Lick, (2501) Lohja, (3819) Robinson and (5261) Eureka obtained by previous workers. Within our sample we distinguish two classes, one that we call monomineralic-olivine asteroids, which are those whose spectra only exhibit the 1μm feature, and another referred to as olivine-rich asteroids, whose spectra exhibit the 1μm feature and a weak (Band II depth ~4%) 2μm feature. For the monomineralic-olivine asteroids the olivine chemistry was found to range from ~Fo49 to Fo70, consistent with the values measured for brachinites and R chondrites. In the case of the olivine-rich asteroids we determined their olivine and low-Ca pyroxene abundance using a new set of spectral calibrations derived from the analysis of R chondrites spectra. We found that the olivine abundance for these asteroids varies from 0.68 to 0.93, while the fraction of low-Ca pyroxene to total pyroxene ranges from 0.6 to 0.9. A search for dynamical connections between the olivine-dominated asteroids and asteroid families found no genetic link (of the type core-mantel-crust) between these objects.

KW - Asteroids

KW - Infrared observations

KW - Meteorites

KW - Spectroscopy

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UR - http://www.scopus.com/inward/citedby.url?scp=84887228596&partnerID=8YFLogxK

U2 - 10.1016/j.icarus.2013.10.006

DO - 10.1016/j.icarus.2013.10.006

M3 - Article

AN - SCOPUS:84887228596

SN - 0019-1035

VL - 228

SP - 288

EP - 300

JO - Icarus

JF - Icarus

ER -

Olivine-dominated asteroids: Mineralogy and origin

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