Asteroid 4197 (1982 TA)


delay-Doppler Imaging


24, 25, and 28 October were devoted to delay-Doppler imaging of 1982 TA. Each of the nine frames above represents about 20 minutes of data from the 24th. Together, these images cover about 90 percent of one rotation. A single pixel in these frames represents the echo power returned by an area spanned by 1 microsecond of round-trip time delay (150 m) and 6 Hertz of Doppler frequency (210 m / cos delta).

The images on top are shown at their raw resolution. Below, the same images have been filtered slightly to help provide a more intuitive picture of the asteroid's signature.

On the 25th, a much longer imaging data set was obtained, despite a two hour interruption due to high winds at Goldstone. Continued observations on 28 October yielded still more images and a refined estimate of the delay to the asteroid.


Asteroid Radar Astronomy