2003 SD220
Discovered on September 29 2003 by LONEOS, Anderson Mesa. Included in the list of the "Potentially Hazardous Asteroids" of the Minor Planet Center.
Orbital and Physical Characteristics
| Epoch | 2021 Jul 05 |
| Mean Anomaly | 357.01326° |
| Argument of Perihelion | 326.93416° |
| Longitude of Ascending Node | 273.91415° |
| Inclination | 8.51459° |
| Eccentricity | 0.2106313 |
| Semimajor Axis | 0.8266941 AU |
| Orbital Period | 0.75 years |
MOID |
0.0180705 AU |
| Orbit type | Aten |
| Absolute Magnitude | 17.56 |
| Diameter | 791±25 m [1]; 600-1200 m [3] |
| Rotation period | 285.0 h [2] |
Radar scattering properties
SC/OC |
0.17 [3] |
| Radar albedo | 0.25 [3] |
Close Approach to the Earth
| Date of encounter | 2021 Dec 17 |
| Distance | 0.03628 AU (14.12 lunar distances) |
Observation Schedule
| Date | Window, UT | Receiver |
Transmitter |
Frequency, MHz |
λ, cm |
Ptx, kW |
R, au |
RTT, sec |
SNR/RTT |
|---|---|---|---|---|---|---|---|---|---|
| 2021 Dec 4 | 12:31 - 13:30 | RT-32 (Sv, Zc, Bd) | DSS-14 [4] | 8560.0 | 3.5 | 440 | 0.05513 | 55 | 6 |
| 2021 Dec 9 | 06:00 - 07:20 | RT-32 (Sv, Zc, Bd) | DSS-14 [4] | 8560.0 | 3.5 | 440 | 0.04501 | 45 | 13 |
| 2021 Dec 10 | 01:25 - 04:30 | RT-32 (Bd) | DSS-14 [4] | 8560.0 | 3.5 | 440 | 0.04348 | 43 | 15 |
| 2021 Dec 20 | 02:35 - 05:20 | RT-32 (Bd) | DSS-14 [4] | 8560.0 | 3.5 | 440 | 0.03707 | 37 | 26 |
| 2021 Dec 21 | 03:02 - 05:10 | RT-32 (Bd) | DSS-14 [4] | 8560.0 | 3.5 | 440 | 0.03788 | 38 | 24 |
Echo power spectrum
Bistatic DSS-14/RT-32 continuous wave echo power spectra of 2003 SD220 obtained at Badary observatory on December 4, 2021 on 5 radar transmit-receive cycles from 12:39 UT and on December 9 from 06:55 to 17:15 UT. Solid and dashed lines denote echo power in the opposite circular (OC) and same circular (SC) polarizations as that of the transmitted wave. The broadening of the obtained spectra corresponds to an asteroid of at least 570 meters on December 4 and at least 1140 meters on December 9, assuming that its rotation period is 285.0 h [2]. These results characterize an object with a noticeably elongated shape, which is consistent with radar observations on December 17-22, 2018.
Remarks
Nugent, C.R. et al., NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos, The Astronomical Journal, 152(3), 2016.
Warner, B.D. et al., 2009.
Yu. S. Bondarenko et al., 2021.
We thank L. A. Benner, S. Naidu, M. Brozovic and the technical staff at Goldstone for the help with the radar observations.