| Autor: |
Shepard, Michael K., Clark, B. E., Ockert-Bell, M., Nolan, M. C., Howell, E. S., Magri, C., Giorgini, J. D., Benner, L. A. M., Ostro, S. J., Harris, A. W., Warner, B. D., Stephens, R. D., Mueller, M. |
| Přispěvatelé: |
Astronomy |
| Jazyk: |
angličtina |
| Rok vydání: |
2009 |
| Zdroj: |
Bulletin of the American Astronomical Society, 41. American Astronomical Society |
| ISSN: |
0002-7537 |
| Popis: |
Using the S-band radar at Arecibo Observatory, we have observed 19 Tholen M-class asteroids. The mean radar albedo for all our targets is 0.28 ± 0.13, considerably higher than the mean radar albedo of every other class (Magri et al. 2007, Icarus 186, 126-151). We find approximately one-third (six) of these 19 objects have radar albedos suggesting a very high metal content (mean 0.43 ± 0.13), consistent with a remnant iron/nickel core interpretation (irons) or exotic high-metal meteorite types (such as CB), and we propose designating these objects Mm-types. A 3 micron spectral absorption feature (usually attributed to hydrated phases) is absent in the four Mm-types that have been observed at that wavelength. The remaining 13 asteroids have moderately high mean radar albedos (mean 0.21 ± 0.06) and are more likely enstatite chondrite (EH/EL), CH, CB, or CI/CM in composition, in order of preference. All of the non-Mm asteroids show a positive correlation between visual and radar albedo. This may indicate that all are of similar composition, with metal abundance being the primary variable affecting their albedo. Acknowledgements: This work was funded by NSF grant AST-0605903 to MKS and AST-0606704 to BEC. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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