Collaborative Observations of Near-Earth Asteroids with the Goldstone and Arecibo Radar Systems

Abstract:

The Goldstone (70-m diameter, 8560 MHz/X band) and Arecibo (305-m diameter, 2380 MHz/S band) solar system radars have long worked independently, yet in tandem, to observe near-Earth asteroids as they make close flybys of Earth. The complementary nature of each site's strengths, Goldstone's maneuverability (and, recently, higher spatial resolution) and Arecibo's higher nominal output power and unmatched collecting area, allow for better constraints on sizes, shapes, spin states, and surface properties of near-Earth asteroids than either system can provide on its own. Here, we will discuss a handful of objects observed with both facilities, including binary asteroids (285263) 1998 QE2 and (153958) 2002 AM31 and contact-binary asteroid (192642) 1999 RD32, and describe how the complementary nature of the Goldstone and Arecibo radars has enhanced our knowledge of these small bodies.

The importance of collaboration between Goldstone and Arecibo will only increase in the future as we look to expand the use of high-resolution bistatic observations of near-Earth asteroids, where both sites simultaneously observe a target. Observations this past June during the close flyby of 2014 HQ124 (Benner et al., this meeting) demonstrated reception at Arecibo of a 40-MHz bandwidth (3.75-m resolution), X-band transmission from Goldstone. Future capabilities of the Deep Space Network (Busch et al., this meeting), such as the 80-MHz (1.875-m resolution) radar on the Goldstone 34-m dish, will benefit greatly from the sensitivity of Arecibo's large aperture.