| Autor: |
Anne K. Virkki, Sean E. Marshall, Flaviane C. F. Venditti, Luisa F. Zambrano-Marín, Dylan C. Hickson, Anna McGilvray, Patrick A. Taylor, Edgard G. Rivera-Valentín, Maxime Devogèle, Eframir Franco Díaz, Sriram S. Bhiravarasu, Betzaida Aponte Hernández, Carolina Rodriguez Sánchez-Vahamonde, Michael C. Nolan, Phil Perillat, Israel Cabrera, Elliot González, Daniel Padilla, Victor Negrón, Juan Marrero, Johbany Lebrón, Adrian Bagué, Francisco Jiménez, Andy López-Oquendo, Daniel Repp, Riley A. McGlasson, Brynn Presler-Marshall, Ellen S. Howell, Jean-Luc Margot, Sanjana Prabhu Desai |
| Přispěvatelé: |
Particle Physics and Astrophysics |
| Rok vydání: |
2022 |
| Předmět: |
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| Zdroj: |
The Planetary Science Journal. 3:222 |
| ISSN: |
2632-3338 |
| DOI: |
10.3847/psj/ac8b72 |
| Popis: |
We successfully observed 191 near-Earth asteroids using the Arecibo Observatory’s S-band planetary radar system from 2017 December through 2019 December. We present radar cross sections for 167 asteroids; circular-polarization ratios for 112 asteroids based on Doppler-echo-power spectra measurements; and radar albedos, constraints on size and spin periods, and surface-feature and shape evaluation for 37 selected asteroids using delay-Doppler radar images with a range resolution of 75 m or finer. Out of 33 asteroids with an estimated effective diameter of at least 200 m and sufficient image quality to give clues of the shape, at least 4 (∼12%) are binary asteroids, including 1 equal-mass binary asteroid, 2017 YE5, and at least 10 (∼30%) are contact-binary asteroids. For 5 out of 112 asteroids with reliable measurements in both circular polarizations, we measured circular-polarization ratios greater than 1.0, which could indicate that they are E-type asteroids, while the mean and the 1σ standard deviation were 0.37 ± 0.23. Further, we find a mean opposite-sense circular-polarization radar albedo of 0.21 ± 0.11 for 41 asteroids (0.19 ± 0.06 for 11 S-complex asteroids). We identified two asteroids, 2011 WN15 and (505657) 2014 SR339, as possible metal-rich objects based on their unusually high radar albedos, and discuss possible evidence of water ice in 2017 YE5. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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