Goldstone Radar Observations Planning: 2020 SW
2020 SW was discovered on September 18, 2020 by the Mt. Lemmon Survey in Arizona. This asteroid will approach within 0.00019 au (0.7 Earth-Moon distances) at 11:12 UT (04:12 am PDT) on 2020 Sep. 24. The approach distance is only about 3.4 Earth radii above the surface. With an absolute magnitude of 28.9, this object is roughly 5-10 meters in diameter. Nothing else is known about its physical properties. In principle, radar SNRs Goldstone would be very strong on Sep. 24 if we could observe the asteroid on that date. The time we were able to schedule on short notice is on Sep. 25 when the distance will be about 0.005 au (roughly 2 lunar distances) and the SNRs will be much weaker. Due to the short round-trip light travel time, the observations will be bistatic with transmission at DSS-14 and reception at DSS-13. Due to the unusual close approach distance, an official NASA statement was released about this object at: https://www.jpl.nasa.gov/news/news.php?feature=7752
Orbital and Physical Characteristics Name 2020 SW Asteroid number not numbered Discoverer Mt. Lemmon Survey Discovery date 2020 Sep 18 orbit type Apollo Close approach distance 0.00019 au (0.7 lunar distances) Close approach date 2020 Sep 24 semimajor axis 1.0149 au eccentricity 0.190 inclination 4.2 deg Orbital period 1.02 years perihelion distance 0.822 au aphelion distance 1.208 au MOID 0.00051 au absolute magnitude (H) 28.9 diameter ~6 meters optical albedo unknown rotation period unknown lightcurve amplitude unknown pole direction unknown spectral class unknown PHA? No Last update: 2020 September 24
2020 SW https://www.minorplanetcenter.net/mpec/K20/K20S83.html
Goldstone SNRs SNRs assume Ptx = 250 kW, D = 6 m, P = 0.5 h, radar albedo = 0.1, Tsys = 17 K. Monostatic at DSS-14 with 1/2 power DSS13 DOY start date window RA, dec dist runs SNR/day SNR/run SNR/RTT 264 2020 Sep 20 02:17-13:00 357, +22 0.014 1409 10 0 265 2020 Sep 21 02:15-12:56 358, +22 0.010 1845 29 1 266 2020 Sep 22 02:14-12:52 358, +22 0.007 2675 130 3 267 2020 Sep 23 02:17-12:49 359, +20 0.004 4880 1500 23 6 268 2020 Sep 24 03:00-10:19 14, +4 0.001 20000 2600000 19000 4700 268-269 2020 Sep 24-25 16:38-00:45 194, -5 0.001 10540 80000 850 210 269-270 2020 Sep 25-26 16:22-01:08 199, +1 0.005 3356 640 12 3 DOY 269 1625-1810 UTC 270-271 2020 Sep 26-27 16:17-01:10 200, +2 0.008 2005 78 2 271-272 2020 Sep 27-28 16:13-01:08 200, +3 0.011 1430 20 1 272-273 2020 Sep 28-29 16:09-01:06 200, +3 0.015 1112 7 0 Goldstone has only one klystron and full power is not expected until Dec. 2020 or Jan. 2021. 2020 SW ARECIBO SNRs start date window RA, dec dist runs SNR/day SNR/run ...Not computed yet...Arecibo is not operational due to a cable failure in August, 2020...
Track Assignments
DOY BOA BOT EOT EOA 269 1455 1625 1810 1840 DSS-14 GSSR AST 2020 SW Transmit 269 1455 1840 DSS-13 DSSR AST 2020 SW Receive only Goldstone tracks: UT UT PDT Duration Round-trip DOY Date TX Window TX Window hh:mm time (sec) SNR/run 269 Sep 25 1625-1810 0925-1110 Sep 25 1:35 5 3 ...Can actually start transmitting a bit earlier when the asteroid rises... Arecibo tracks: UT UT PST Round-trip Date TX Window TX Window time (sec) ...Not scheduled...
Uncertainties
2020 SW JPL/Horizons solution 5, #obs: 191 (6 days) 2020 Sep 24 Date__(UT)__HR:MN R.A._(a-appar)_DEC. delta POS_3sigma DOP_S_3sig DOP_X_3sig RT_delay_3sig 2020-Sep-20 00:00 *m 357.40825 22.25211 0.01486050031517 0.352 15.61 56.74 0.002464 2020-Sep-21 00:00 *m 357.64441 22.04443 0.01157567953460 0.341 15.54 56.47 0.001899 2020-Sep-22 00:00 *m 358.07700 21.64665 0.00829090637240 0.342 15.43 56.09 0.001337 2020-Sep-23 00:00 *m 359.09006 20.69524 0.00499857284069 0.396 15.22 55.31 0.000782 2020-Sep-24 00:00 *m 3.98338 15.87444 0.00167559372219 0.733 14.17 51.49 0.000250 2020-Sep-25 00:00 *m 195.27653 -2.84183 0.00187363826032 60.981 15.00 54.52 0.000266 2020-Sep-26 00:00 *m 198.96441 1.36181 0.00519312391589 59.976 16.02 58.23 0.000801 2020-Sep-27 00:00 *m 199.76221 2.29291 0.00848436620899 59.856 16.26 59.11 0.001358 2020-Sep-28 00:00 *m 200.09834 2.70368 0.01176893946514 59.786 16.41 59.63 0.001922 2020-Sep-29 00:00 * 200.27310 2.93354 0.01505447580618 59.713 16.53 60.06 0.002492 The pointing uncertainties are still uncomfortably large for Goldstone so additional astrometry obtained up to about 12:00 UT on Sep. 24 would be helpful. - - - - - - - - - - JPL/Horizons solution 4, # obs: 76 (5 days) 2020 September 23 Date__(UT)__HR:MN R.A._(a-appar)_DEC. delta POS_3sigma DOP_S_3sig DOP_X_3sig RT_delay_3sig 2020-Sep-21 00:00 *m 357.64442 22.04441 0.01157566596598 0.473 61.25 222.61 0.008195 2020-Sep-22 00:00 *m 358.07703 21.64661 0.00829101191681 0.645 60.79 220.94 0.006018 2020-Sep-23 00:00 *m 359.09008 20.69518 0.00499879817494 1.289 59.83 217.43 0.003910 2020-Sep-24 00:00 *m 3.98242 15.87524 0.00167594407169 20.640 54.87 199.41 0.002069 2020-Sep-25 00:00 *m 195.27316 -2.84513 0.00187317762678 291.574 59.86 217.54 0.001413 2020-Sep-26 00:00 *m 198.96258 1.36035 0.00519255212274 269.427 63.70 231.52 0.002852 * 2020-Sep-27 00:00 *m 199.76059 2.29169 0.00848367815331 266.716 64.59 234.76 0.004904 2020-Sep-28 00:00 *m 200.09678 2.70256 0.01176813336539 265.619 65.13 236.73 0.007073 2020-Sep-29 00:00 * 200.27159 2.93247 0.01505355070675 264.892 65.61 238.44 0.009289 - - - - - - - - - - JPL/Horizons solution 3, # obs: 57 (4 days) 2020 Sep 22 Date__(UT)__HR:MN R.A._(a-appar)_DEC. delta POS_3sigma DOP_S_3sig DOP_X_3sig RT_delay_3sig 2020-Sep-21 00:00 *m 357.64443 22.04441 0.01157563230713 0.902 146.41 532.11 0.010110 2020-Sep-22 00:00 *m 358.07703 21.64662 0.00829099192288 0.982 146.04 530.77 0.006723 2020-Sep-23 00:00 *m 359.09008 20.69521 0.00499879173270 10.131 145.81 529.94 0.006692 2020-Sep-24 00:00 *m 3.98239 15.87539 0.00167595077759 198.536 145.94 530.41 0.010102 2020-Sep-25 00:00 *m 195.27381 -2.84481 0.00187315932187 323.303 130.80 475.37 0.014094 2020-Sep-26 00:00 *m 198.96325 1.36064 0.00519252098415 371.163 146.24 531.49 0.018648 * 2020-Sep-27 00:00 *m 199.76127 2.29198 0.00848363348115 383.335 149.82 544.53 0.023622 2020-Sep-28 00:00 *m 200.09747 2.70285 0.01176807490332 387.513 151.62 551.07 0.028768 2020-Sep-29 00:00 * 200.27227 2.93275 0.01505347826156 389.321 152.97 555.95 0.034017
Apparent Magnitudes, Solar Elongations, Lunar Elongations, and Lunar Illumination: Date__(UT)__HR:MN R.A._(a-appar)_DEC. delta APmag S-brt S-O-T /r T-O-M/MN_Illu% 2020-Sep-18 00:00 357.07075 22.50968 0.02143980531575 21.752 n.a. 155.6911 /L 153.1/ 0.6341 2020-Sep-19 00:00 357.15410 22.45886 0.01814458432870 21.372 n.a. 156.1537 /L 151.4/ 3.7535 2020-Sep-20 00:00 357.27675 22.36126 0.01485615369733 20.918 n.a. 156.6383 /T 143.7/ 9.6396 2020-Sep-21 00:00 357.47480 22.18366 0.01157175015264 20.354 n.a. 157.1820 /T 132.9/ 17.8002 2020-Sep-22 00:00 357.83973 21.84001 0.00828721695883 19.603 n.a. 157.8819 /T 121.1/ 27.5806 2020-Sep-23 00:00 358.69861 21.01517 0.00499459581750 18.461 n.a. 159.0894 /T 109.3/ 38.2828 2020-Sep-24 00:00 2.87571 16.83615 0.00166769499019 15.926 n.a. 163.6488 /L 98.9/ 49.2564 2020-Sep-25 00:00 196.10431 -2.06992 0.00189367021190 29. n.a. 13.9547 /T 88.2/ 59.9470 2020-Sep-26 00:00 199.25280 1.62436 0.00521588943845 30. n.a. 16.4311 /T 99.9/ 69.9070 2020-Sep-27 00:00 199.93910 2.45102 0.00850726839146 31. n.a. 16.4843 /T 112.3/ 78.7866 2020-Sep-28 00:00 200.22684 2.81676 0.01179157092611 32. n.a. 16.1056 /T 124.6/ 86.3174 2020-Sep-29 00:00 200.37450 3.02150 0.01507669097090 32. n.a. 15.5889 /T 136.7/ 92.2992 2020-Sep-30 00:00 200.45586 3.15003 0.01836712793430 33. n.a. 15.0233 /T 148.6/ 96.5911 After closest approach this object gets too close to the Sun for optical observations. Hourly intervals straddling the closest approach: 2020-Sep-23 18:00 0.81145 18.93711 0.00250655975470 16.883 n.a. 161.5234 /T 101.0/ 46.5197 2020-Sep-23 19:00 1.05644 18.69144 0.00236726610248 16.750 n.a. 161.7870 /T 100.6/ 46.9768 2020-Sep-23 20:00 1.33129 18.41463 0.00222779080548 16.608 n.a. 162.0791 /L 100.3/ 47.4335 2020-Sep-23 21:00 1.64187 18.10034 0.00208811658539 16.456 n.a. 162.4047 /L 99.9/ 47.8899 2020-Sep-23 22:00 1.99571 17.74034 0.00194822404674 16.293 n.a. 162.7697 /L 99.5/ 48.3458 2020-Sep-23 23:00 2.40262 17.32380 0.00180809151075 16.117 n.a. 163.1815 /L 99.2/ 48.8014 2020-Sep-24 00:00 2.87571 16.83615 0.00166769499020 15.926 n.a. 163.6488 /L 98.9/ 49.2564 2020-Sep-24 01:00 3.43279 16.25734 0.00152700850347 15.716 n.a. 164.1818 /L 98.6/ 49.7110 2020-Sep-24 02:00 4.09881 15.55899 0.00138600515622 15.484 n.a. 164.7919 /L 98.4/ 50.1650 2020-Sep-24 03:00 4.90982 14.69952 0.00124465994153 15.226 n.a. 165.4887 /L 98.3/ 50.6184 2020-Sep-24 04:00 5.92001 13.61556 0.00110295646171 14.936 n.a. 166.2728 /L 98.2/ 51.0712 2020-Sep-24 05:00 7.21495 12.20555 0.00096090298627 14.606 n.a. 167.1108 /L 98.3/ 51.5234 2020-Sep-24 06:00 8.93842 10.29635 0.00081857224145 14.229 n.a. 167.8599 /L 98.5/ 51.9749 2020-Sep-24 07:00 11.35295 7.56806 0.00067620737238 13.807 n.a. 168.0432 /L 99.1/ 52.4257 2020-Sep-24 08:00 14.99657 3.36491 0.00053453753494 13.359 n.a. 166.3389 /L 100.2/ 52.8757 2020-Sep-24 09:00 21.17878 -3.84758 0.00039588343446 12.923 n.a. 159.9381 /L 102.2/ 53.3249 2020-Sep-24 10:00 34.10459 -18.08502 0.00026894129089 12.580 n.a. 142.9672 /L 105.8/ 53.7733 2020-Sep-24 11:00 73.40429 -43.93495 0.00019036955506 13.035 n.a. 102.5410 /L 108.3/ 54.2209 2020-Sep-24 12:00 145.91409 -42.63111 0.00022862614230 16. n.a. 52.7429 /L 99.7/ 54.6675 2020-Sep-24 13:00 171.81059 -27.18460 0.00034409736054 20. n.a. 28.0937 /L 92.4/ 55.1133 2020-Sep-24 14:00 181.17977 -18.56319 0.00047995588117 24. n.a. 17.7873 /L 89.2/ 55.5581 2020-Sep-24 15:00 185.92692 -13.60520 0.00062089365290 27. n.a. 13.4225 /T 87.7/ 56.0019 2020-Sep-24 16:00 188.80511 -10.44240 0.00076312074432 29. n.a. 11.8258 /T 87.0/ 56.4447 2020-Sep-24 17:00 190.74357 -8.25892 0.00090550800846 29. n.a. 11.4992 /T 86.7/ 56.8865 2020-Sep-24 18:00 192.14166 -6.66257 0.00104768217887 29. n.a. 11.6960 /T 86.6/ 57.3272 2020-Sep-24 19:00 193.19969 -5.44468 0.00118952313609 29. n.a. 12.0780 /T 86.7/ 57.7667
Setups
The rotation period is unknown, but presumably this object will be a relatively rapid rotator, so the bandwidth could be roughly 1 Hz. CW setup: --------------------------------------------------------------------------- TX polarization RCP RCV polarization LCP & RCP Frequency hops: no hopping Bandwidth: 5000 Hz TXoffset +500 Hz FFT 5000 for 1.0 Hz resolution Ranging setups: --------------------------------------------------------------------------- 10-usec baud 10 usec code 127 PRP 1270 usec ncoh 1 bandwidth 787 Hz FFT 128 resolution 6.15 Hz TXoffset +100 Hz (echo in column 80) --------------------------------------------------------------------------- 11-usec baud 11 usec code 127 PRP 1397 usec ncoh 1 bandwidth 716 Hz FFT 128 resolution 5.6 Hz TXoffset +100 Hz (echo in column 82) ------------------------------------------------------------------------- 1-usec baud 1 usec code 255 ncoh 8 bandwidth 245 Hz FFT 128 resolution 3.8 Hz TXoffset +50 Hz (echo in column 116) ---------------------------------------------------------------------
Instructions
NOTE: Data should be moved to the appropriate subdirectories in aardvark:/export/data0/2020sw/raw/
POINTING:
OSOD and predicts will be on aardvark: ...not available yet... POINTING TX Offsets Date (UTC) DOY hhmmss RA Dec Macro LHA Dec RTT OSOD ... to be added ... Transmit offsets are given in millidegrees.
PRDX.OUT.14f-14-14.?? TRANSMITTER: STATION #14, RECEIVER: STATION #14 RECEIVER U.T. RANGE DOPPLER LHA DEC RA EL
2020 SW GOLDSTONE MASTERLOG
============================================================================== Receive TX Setup hops dwell code ncoh FFT runs start -stop OSOD offset Poln Notes ------------------------------------------------------------------------------
Dr. Lance A. M. Benner | PHONE: (818) 354-7412 Mail Stop 183-601 | FAX: (818) 393-4445 Jet Propulsion Laboratory | email: lance.benner@jpl.nasa.gov California Institute of Technology | Plan: To live long and prosper Pasadena, CA 91109-8099 https://echo.jpl.nasa.gov/asteroids/2020SW/2020SW.2020.goldstone.planning.html
Asteroid Radar Astronomy