| 16th of November 2023 |
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| Bistatic radar observations of the asteroid 2003 UC20 |
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The asteroid 2003 UC20
was discovered by the Lincoln Near-Earth Asteroid Research (LINEAR) project
in October, 2003.
(LINEAR was responsible for the majority of asteroid discoveries from
1998 until it was overtaken by the Catalina Sky Survey in 2005.)
2003 UC20 has a diameter of almost 2 km, an unusually slow rotation period of ~29.6 hours, and a lightcurve
that suggests an elongated shape.
The combination of its size, and the fact that
its orbit around the sun brings it within 7.5 million km (20 lunar distances) of the Earth,
has resulted in the Minor Planet Center designating this object as a "Potentially Hazardous Asteroid."
2003 UC20 passed by the Earth on November 2nd at a distance of 5.3 million km, or 13.6 Lunar distances.
Bistatic radar observations were made, transmitting a tone at 7.1 GHz from
the 70m DSS-43 antenna at Tidbinbilla toward the asteroid, with the reflected signal
detected at the ATCA. The image above shows the detection of a strong return signal
in just the first 10 minutes of data.
The y-axis is amplitude in arbitrary units, the y-axis is the frequency
offset from the predicted return frequency in hertz.
Tidbinbilla transmits a Right Circularly Polarised (RCP) tone.
The orange line is the detected Left Circularly Polarised return signal
(as the sense of polarisation is reversed upon reflection).
The fact there is also a weaker RCP return signal provides information on the
surface roughness of the asteroid.
Previous ADAP's have illustrated other observations made as part of the Southern Hemisphere Asteroid Radar Program (SHARP): of the asteroids Florence in 2017, 2020WU5 in 2021, and 2005 LW3 earlier this year. (Image credit: Shinji Horiuchi) |