Radar images of asteroid 1627 Ivar

Ostro, S. J., D. B. Campbell, A. A. Hine, I. I. Shapiro, J. F. Chandler, C. L. Werner, and K. D. Rosema (1990). Astron. J. 99, 2012-2018.

Radar echoes from the near-earth asteroid 1627 Ivar, whose orbit crosses the Earth's, reveal it to be about twice as long as it is wide, with a maximum dimension no less than 7 km and probably within 20% of 12 km. The surface is fairly smooth at centimeter-to-meter scales but appears irregular and nonconvex at kilometer scales.

Asteroid Radar Astronomy Publications