|
|||||
|
|
Minor element evidence that Asteroid 433 Eros is a space-weathered ordinary chondrite parent body |
|
| Authors: | CN Foley TJ McCoy MRM Brown RD Starr |
| Institution: | a Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305, USA b Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0119, USA c NASA Goddard Spaceflight Center, Bldg. 2, Code 691, Greenbelt, MD 20771, USA d Department of Geological Sciences, Arizona State University, Tempe, AZ 85287-1404, USA e Department of Physics, The Catholic University of America, Washington, DC 20064, USA |
| Abstract: | The NEAR mission to 433 Eros provided detailed data on the geology, mineralogy, and chemistry of this S-class asteroid McCoy, T.J., Robinson, M.S., Nittler, L.R., Burbine, T.H., 2002. Chem. Erde 62, 89-121; Cheng, A.F., 1997. Space Sci. Rev. 82, 3-29] with a key science goal of understanding the relationship between asteroids and meteorites Cheng, A.F., 1997. Space Sci. Rev. 82, 3-29; Gaffey, M.J., Burbine, T.H., Piatek, J.L., Reed, K.L., Chaky, D.A., Bell, J.F., Brown, R.H., 1993a. Icarus 106, 573-602]. Previously reported major element data revealed a bulk surface similar to that of ordinary chondrites, with the notable exception of sulfur, which was highly depleted Trombka, J.I., and 23 colleagues, 2000. Science 289, 2101-2105; Nittler, L.R., and 14 colleagues, 2001. Meteorit. Planet. Sci. 36, 1673-1695]. The origin of this sulfur deficiency, and hence the fundamental nature of the asteroid's surface, has remained controversial. We report a new analysis of NEAR X-ray spectrometer data, indicating that Eros has Cr/Fe, Mn/Fe, and Ni/Fe ratios similar to ordinary chondrite meteorites of type LL or L. Chondritic levels of Cr, Mn, and Ni argue strongly against a partial melting explanation for the sulfur depletion. Instead, our results provide definitive evidence that Eros is a primitive body with composition and mineralogy similar to ordinary chondrites, but with a surface heavily modified by interactions with the solar wind and micrometeorites, processes collectively termed space weathering. |
| Keywords: | Asteroids composition Solar radiation Meteorites Spectroscopy Asteroids surfaces |
| 本文献已被 ScienceDirect 等数据库收录！ | |