DPS Meeting, Madison, October 1998
Session 7. Asteroid Observations II
Contributed Oral Parallel Session, Monday, October 12, 1998, 10:30-11:30am, Madison Ballroom D

[Previous] | [Session 7] | [Next]

[7.04] A Recent Radar Observation of Asteroid 1566 Icarus

P. R. Mahapatra, S. J. Ostro, L. A. M. Benner, K. D. Rosema, R. F. Jurgens, R. Winkler, R. Rose, J. D. Giorgini, D. K. Yeomans, M. A. Slade (JPL)

We report Doppler-only radar observations of 1566 Icarus at Goldstone at a transmitter frequency of 8510 MHz (3.5 cm wavelength) during 1996 June 8-10, the first radar detection of the object since 1968. Optimally filtered and folded spectra achieve a maximum opposite-circular (OC) polarization signal-to-noise ratio of about 10 and help to constrain Icarus' physical properties. We obtain an OC radar cross section of 0.05 square kilometers (±35%), which is about one-half that estimated by Goldstein (1969, Icarus 10, 430) and by Pettengill et al. (1969, Icarus 10, 432), and a circular polarization ratio of 0.5 ±0.2. We analyze the echo power spectrum with a model incorporating the echo bandwidth B and a spectral shape parameter n, yielding a coupled constraint between B and n. We adopt 25 Hz as the lower bound on B, which gives a lower bound on the maximum pole-on breadth of about 0.6 km, and upper bounds on the radar and optical albedos that are consistent with Icarus' QS-class taxonomy. The observed circular polarization ratio indicates a very rough near-surface at spatial scales near the radar wavelength.

The author(s) of this abstract have provided an email address for comments about the abstract: pravas@rhyme.jpl.nasa.gov

[Previous] | [Session 7] | [Next]