Spectral properties of near-earth asteroids: Evidence for sources of ordinary chondrite meteorites

Science

Volumn 273, Issue 5277, 1996, Pages 946-948

  Binzel, Richard P ^a   Bus, Schelte J ^a   Burbine, Thomas H ^a   Sunshine, Jessica M ^a,b  

^a MASSACHUSETTS INSTITUTE OF TECHNOLOGY   (United States)

^b SCIENCE APPLICATIONS INTERNATIONAL CORPORATION   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ARTICLE; METEOROLOGY; PRIORITY JOURNAL; SPECTROSCOPY;

ASTEROIDEA;

ASTEROID; CHONDRITE (ORDINARY); PROVENANCE; SPECTRAL PROPERTIES;

EID: 0029663180     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.273.5277.946     Document Type: Article

References (33)

1. H. Y. McSween, Meteorites and Their Source Bodies (Cambridge Univ. Press, New York, 1987).
2. We define near-Earth asteroids on the basis of their orbital characteristics. For this work, we specifically refer to asteroids categorized as Aten, Apollo, and Amor objects. Aten and Apollo asteroids have orbits that cross the orbit of Earth. Amor asteroids approach within 0.3 astronomical unit of Earth's orbit.
3. G. W. Watherill, Philos. Trans. R. Soc. London Ser. A 323, 323 (1987); J. Wisdom, Icarus 56, 51 (1983); Nature 315, 731 (1985); R. P. Binzel, S. Xu, S. J. Bus, E. Bowell, Science 257, 779 (1992).
4. G. W. Watherill, Philos. Trans. R. Soc. London Ser. A 323, 323 (1987); J. Wisdom, Icarus 56, 51 (1983); Nature 315, 731 (1985); R. P. Binzel, S. Xu, S. J. Bus, E. Bowell, Science 257, 779 (1992).
5. G. W. Watherill, Philos. Trans. R. Soc. London Ser. A 323, 323 (1987); J. Wisdom, Icarus 56, 51 (1983); Nature 315, 731 (1985); R. P. Binzel, S. Xu, S. J. Bus, E. Bowell, Science 257, 779 (1992).
6. G. W. Watherill, Philos. Trans. R. Soc. London Ser. A 323, 323 (1987); J. Wisdom, Icarus 56, 51 (1983); Nature 315, 731 (1985); R. P. Binzel, S. Xu, S. J. Bus, E. Bowell, Science 257, 779 (1992).
7. D. J. Tholen and M. A. Barucci, in Asteroids II, R. P. Binzel, T. Gehrels, M. S. Matthews, Eds. (Univ. of Arizona Press, Tucson, 1989), pp. 298-315.
8. L. A. McFadden, M. J. Gaffey, T. B. McCord, Science 229, 160 (1985).
9. Asteroid 1862 Apollo is the only object currently assigned to the taxonomic class Q, which is the OC analog case we consider here. Two other potential OC-like asteroids have been reported, but both have spectra that differ from that of Apollo. Asteroid 6611 (1993 VW) is a near-Earth asteroid measured by M. Di Martino, A. Manara, and F. Migliorini [Astron. Astrophys. 302, 609 (1995)]. A potential main-belt asteroid OC analog, 3628 Boznemcova, is discussed by R. P. Binzel et al. [Science 262, 1541 (1993)]. Near-Earth asteroids found to have spectra revealing other spectral types (for example, C types) will be discussed elsewhere (R. P. Binzel et al., in preparation).
10. Asteroid 1862 Apollo is the only object currently assigned to the taxonomic class Q, which is the OC analog case we consider here. Two other potential OC-like asteroids have been reported, but both have spectra that differ from that of Apollo. Asteroid 6611 (1993 VW) is a near-Earth asteroid measured by M. Di Martino, A. Manara, and F. Migliorini [Astron. Astrophys. 302, 609 (1995)]. A potential main-belt asteroid OC analog, 3628 Boznemcova, is discussed by R. P. Binzel et al. [Science 262, 1541 (1993)]. Near-Earth asteroids found to have spectra revealing other spectral types (for example, C types) will be discussed elsewhere (R. P. Binzel et al., in preparation).
11. Asteroid 1862 Apollo is the only object currently assigned to the taxonomic class Q, which is the OC analog case we consider here. Two other potential OC-like asteroids have been reported, but both have spectra that differ from that of Apollo. Asteroid 6611 (1993 VW) is a near-Earth asteroid measured by M. Di Martino, A. Manara, and F. Migliorini [Astron. Astrophys. 302, 609 (1995)]. A potential main-belt asteroid OC analog, 3628 Boznemcova, is discussed by R. P. Binzel et al. [Science 262, 1541 (1993)]. Near-Earth asteroids found to have spectra revealing other spectral types (for example, C types) will be discussed elsewhere (R. P. Binzel et al., in preparation).
12. C. M. Pieters, Meteoritics 19, 290 (1984); G. W. Wetherill and C. R. Chapman, in Meteorites and the Early Solar System. J. F. Kerridge and M. S. Matthews, Eds. (Univ. of Arizona Press, Tucson, 1988), pp. 35-67; C. M. Pieters, E. M. Fischer, O. Rode, A. Basu, J. Geophys. Res. 98, 20817 (1993).
13. C. M. Pieters, Meteoritics 19, 290 (1984); G. W. Wetherill and C. R. Chapman, in Meteorites and the Early Solar System. J. F. Kerridge and M. S. Matthews, Eds. (Univ. of Arizona Press, Tucson, 1988), pp. 35-67; C. M. Pieters, E. M. Fischer, O. Rode, A. Basu, J. Geophys. Res. 98, 20817 (1993).
14. C. M. Pieters, Meteoritics 19, 290 (1984); G. W. Wetherill and C. R. Chapman, in Meteorites and the Early Solar System. J. F. Kerridge and M. S. Matthews, Eds. (Univ. of Arizona Press, Tucson, 1988), pp. 35-67; C. M. Pieters, E. M. Fischer, O. Rode, A. Basu, J. Geophys. Res. 98, 20817 (1993).
15. J. F. Bell, D. R. Davis, W. K. Hartmann, M. J. Gaffey, in (4), pp. 921-945.
16. S. Xu, R. P. Binzel, T. H. Burbine, S. J. Bus, Icarus 115, 1 (1995).
17. S-class asteroids display a diverse range of mineralogies. One subset, denoted as S(IV), appears to have a silicate mineralogy most analogous to OC meteorites [M. J. Gaffey et al., Icarus 106, 573 (1993)].
18. 2+.
19. The taxonomic classification for 4 Vesta is V. Numerous small main-belt asteroids having the same classification appear to be related to Vesta (13). (A second related set of small asteroids related to Vesta, denoted the J class, have the same mismatch seen in Fig. 1A at 0.8 μm.) Asteroid 349 Dembowska is the only object currently assigned to taxonomic class R (4).
20. R. P. Binzel and S. Xu, Science 260, 186 (1993).
21. M. J. Gaffey, J. F. Bell, D. P. Cruikshank, in (4), pp. 98-127.
22. M. J. Gaffey, T. H. Burbine, R. P. Binzel, Meteoritics 28, 161 (1993).
23. M. J. Gaffey, J. Geophys. Res. 81, 905 (1976). We account for the 0.025-μm wavelength calibration error in these data [as reported on p. 91 of M. J. Gaffey, Icarus 60, 83 (1984)].
24. M. J. Gaffey, J. Geophys. Res. 81, 905 (1976). We account for the 0.025-μm wavelength calibration error in these data [as reported on p. 91 of M. J. Gaffey, Icarus 60, 83 (1984)].
25. Notable exceptions in our data set are the two largest near-Earth asteroids, 433 Eros and 1036 Ganymede, which have estimated diameters of >20 and >50 km, respectively. Three other sampled objects, 1627 Ivar, 1866 Sisyphus, and 4954 Eric, may have diameters of >10 km. For the remaining 30 objects in our sample, the estimated mean diameter is 3 km. Because the bulk of our observations span such a narrow size range, the observed variations in band depth are not part of a diameter-dependent trend reported in (10).
26. M. J. Gaffey, Lunar. Planet. Sci. Conf. XXVII, 391 (1996).
27. D. R. Davis, S. J. Weidenschilling, P. Farinella, P. Paolicchi, R. P. Binzel, in (4), pp. 805-826.
28. C. R. Chapman et al., Nature 374, 783 (1995); C. R. Chapman, in preparation.
29. C. R. Chapman et al., Nature 374, 783 (1995); C. R. Chapman, in preparation.
30. B. Zellner, D. J. Tholen, E. F. Tedesco, Icarus 61, 355 (1985).
31. The dispersion within our spectrograph is about 25 Å per pixel. To achieve a higher signal-to-noise ratio for compact plotting in this report, we further binned our data in 10-pixel increments with the resulting points and error bars representing the weighted least squares average of each independent 10-pixel sample.
32. The following near-Earth asteroid spectra are presented in Fig. 3B: 433, 1036, 1620, 1627, 1864, 1866, 2062, 2063, 2102, 4179, 4954, 5143, 5626, 5660, 6053, 6489, 6455, 6569, 1989 VA, 1991 BB, 1991 VK, 1991 WA, 1991 XB, 1992 CC1, 1993 TQ2, 1993 UB, 1993 WD, 1993 XN2, 1994 AB1, 1994 AW1, 1994 EF2, 1994 TW1, 1995 BL2, 1995 WL8, and 1995 YA3.
33. Data reported here were obtained at the MDM Observatory. This work was supported by NASA grants NAGW1450, NAGW3901, and NASW5026 and by a National Science Foundation Presidential Young Investigator Award (R.P.B.). A grant from the Planetary Society provided additional access to the telescope essential for the success of this project. We thank B. G. Marsden, G. V. Williams, and E. L. G. Bowell for assistance with ephemerides for newly discovered objects and M. Gaffey and an anonymous referee for helpful reviews.