RADAR DETECTIONS IN CHRONOLOGICAL ORDER Radar Detection Discovery Order Asteroid a (AU) e i (deg) H (mag) Q (AU) q (AU) Date Observatory Technique ===== ======== ====== = ======= ======= ====== ====== ==== =========== ========= 0 1866 Sisyphus 1.894 0.539 41.2 13.0 2.914 0.873 Dec 1985 Arecibo Radar 1 185851 2000 DP107 TOO PHA 1.365 0.377 8.7 18.2 1.880 0.850 Sep 2000 Goldstone & Arecibo Radar Aug 2008 Arecibo & Goldstone 2 2000 UG11 TOO PHA 1.934 0.573 8.9 20.4 3.042 0.826 Nov 2000 Arecibo & Goldstone Radar 3 66391 1999 KW4 PHA 0.642 0.688 38.9 16.3 1.084 0.200 May 2001 Goldstone & Arecibo Radar Jun 2002 Arecibo 4 1998 ST27 PHA 0.819 0.530 21.0 19.4 1.253 0.385 Oct 2001 Arecibo Radar Oct 2004 Arecibo 5 2002 BM26 TOO PHA 1.832 0.444 16.2 19.8 2.645 1.019 Feb 2002 Arecibo Radar 6 2002 KK8 TOO PHA 1.967 0.469 24.6 20.5 2.889 1.045 Jun 2002 Arecibo Radar 7 5381 Sekhmet 0.948 0.296 49.0 16.5 1.228 0.667 May 2003 Arecibo Radar 8 66063 1998 RO1 0.991 0.720 22.7 17.9 1.705 0.277 Sep 2003 Arecibo Photometry Sep 2004 Arecibo 9 2003 SS84 TOO PHA 1.932 0.572 5.5 21.7 3.037 0.827 Sep 2003 Arecibo & Goldstone Radar 10 69230 Hermes TOO PHA 1.654 0.624 6.1 17.5 2.686 0.622 Oct 2003 Arecibo & Goldstone Radar 11 162000 1990 OS PHA 1.680 0.463 1.1 20.0 2.458 0.902 Nov 2003 Arecibo Radar (Aug 1990 Goldstone Satellite not detected) 12 65803 Didymos PHA 1.642 0.383 3.4 17.9 2.275 1.013 Nov 2003 Arecibo, Goldstone Photometry, Radar 13 85938 1999 DJ4 PHA 1.851 0.483 9.2 18.4 2.745 0.957 Apr 2004 Arecibo Photometry 14 164121 2003 YT1 TOO PHA 1.110 0.292 44.1 16.2 1.434 0.785 May 2004 Arecibo Radar 15 276049 2002 CE26 2.233 0.559 47.4 16.5 3.481 0.984 Aug 2004 Arecibo Radar Possible triple 16 2005 AB TOO 3.217 0.656 8.2 17.3 5.325 1.107 Feb 2005 Arecibo Photometry 17 1994 XD TOO PHA 2.356 0.730 4.3 19.1 4.076 0.637 Jun 2005 Arecibo Radar 18 1862 Apollo PHA 1.471 0.560 6.4 16.3 2.295 0.647 Oct 2005 Arecibo Radar (Nov 1980 Arecibo Satellite not detected) 19 2006 GY2 TOO PHA 1.853 0.494 30.6 18.7 2.768 0.938 May 2006 Arecibo & Goldstone Radar 20 2004 DC PHA 1.634 0.400 19.4 18.0 2.288 0.981 Jun 2006 Arecibo & Goldstone Radar 21 2006 VV2 TOO PHA 2.388 0.602 23.6 16.6 3.826 0.949 Mar 2007 Goldstone & Arecibo Radar 22 2007 DT103 TOO PHA 2.210 0.574 5.4 19.4 3.480 0.941 Jul 2007 Goldstone Radar 23 153591 2001 SN263 1.987 0.478 6.7 16.9 2.938 1.037 Feb 2008 Arecibo Radar TRIPLE 24 2005 NB7 PHA 2.042 0.516 12.7 18.7 3.096 0.988 Apr 2008 Arecibo & Goldstone Radar 25 2008 BT18 TOO PHA 2.222 0.598 8.1 18.2 3.551 0.894 Jul 2008 Arecibo & Goldstone Radar 26 35107 1991 VH PHA 1.136 0.144 13.9 16.7 1.300 0.973 Jul 2008 Arecibo & Goldstone Photometry 27 136617 1994 CC PHA 1.638 0.417 4.7 17.7 2.321 0.955 Jun 2009 Goldstone & Arecibo Radar TRIPLE 28 2000 CO101 PHA 1.075 0.090 15.3 19.0 1.172 0.979 Sep 2009 Arecibo Radar 29 175706 1996 FG3 PHA 1.054 0.350 2.0 18.0 1.423 0.685 Nov 2011 Arecibo Photometry "date" refers to the first radar apparition that showed evidence of a binary. 1990 OS was observed in 1990 but did not show evidence for a secondary until it was observed again in 2003. Similarly, Apollo was observed by radar in 1980 but its satellite was not detected until 2005. Consequently, radar observations that did not yield detections of secondaries are excluded from this list (e.g., 1990 OS at Goldstone in 2003, Apollo at Goldstone in 2005, and 2000 CO101 at Goldstone in 2009). With 2006 GY2, there was a suggestion of a satellite in Goldstone CW data on May 13, but it wasn't obviously a binary until radar imaging at Arecibo on May 15. May 16 Goldstone data also showed two objects. With Didymos, we did not realize that the Goldstone data showed both components until Sep. 2009. 1866 Sisyphus is now listed as a binary based on CW data obtained at Arecibo in December, 1985. The CW signature matches those subsequently seen many times with other binary NEAs. Attempts to detect the secondary with ranging observations in 1985 were unsuccessful. TOO indicates targets-of-opportunity. PHA = "Potentially Hazardous Asteroid" as defined by the Minor Planet Center Binaries and triples discovered by radar that have been targets-of-opportunity: 12/23 = 52.2% Percentage of radar binaries and triples classified as "Potentially Hazardous:" 23/29 = 79.3%
RADAR DETECTIONS ORDERED BY ASTEROID NUMBER AND PROVISIONAL DESIGNATION Asteroid a (AU) e i (deg) H (mag) Q (AU) q (AU) Order Date Observatory ======== ====== = ======= ======= ====== ====== ===== ==== =========== 1862 Apollo 1.471 0.560 6.4 16.3 2.295 0.647 PHA 18 Oct 2005 Arecibo 1866 Sisyphus 1.894 0.539 41.2 13.0 2.914 0.873 0 Dec 1985 Arecibo 5381 Sekhmet 0.948 0.296 49.0 16.5 1.228 0.667 7 May 2003 Arecibo 35107 1991 VH 1.136 0.144 13.9 16.7 1.300 0.973 PHA 26 Jul 2008 Arecibo 65803 Didymos 1.642 0.383 3.4 17.9 2.275 1.013 PHA 12 Nov 2003 Arecibo 66063 1998 RO1 0.991 0.720 22.7 17.9 1.705 0.277 8 Sep 2003 Arecibo 66391 1999 KW4 0.642 0.688 38.9 16.3 1.084 0.200 PHA 3 May 2001 Goldstone & Arecibo 69230 Hermes 1.654 0.624 6.1 17.5 2.686 0.622 PHA 10 Oct 2003 Arecibo & Goldstone 85938 1999 DJ4 1.851 0.483 9.2 18.4 2.745 0.957 PHA 12 Apr 2004 Arecibo 136617 1994 CC 1.638 0.417 4.7 17.7 2.321 0.955 PHA 27 Jun 2009 Goldstone & Arecibo 153591 2001 SN263 1.987 0.478 6.7 16.9 2.938 1.037 23 Feb 2008 Arecibo 162000 1990 OS 1.680 0.463 1.1 20.0 2.458 0.902 PHA 11 Nov 2003 Arecibo 164121 2003 YT1 1.110 0.292 44.1 16.2 1.434 0.785 PHA 14 May 2004 Arecibo 175706 1996 FG3 1.054 0.350 2.0 18.0 1.423 0.685 PHA 29 Nov 2011 Arecibo 185851 2000 DP107 1.365 0.377 8.7 18.2 1.880 0.850 PHA 1 Sep 2000 Goldstone & Arecibo 276049 2002 CE26 2.233 0.559 47.4 16.5 3.481 0.984 15 Aug 2004 Arecibo 1994 XD 2.356 0.730 4.3 19.1 4.076 0.637 PHA 17 Jun 2005 Arecibo 1998 ST27 0.819 0.530 21.0 19.4 1.253 0.385 PHA 4 Oct 2001 Arecibo 2000 CO101 1.075 0.090 15.3 19.0 1.172 0.979 PHA 28 Sep 2009 Arecibo 2000 UG11 1.934 0.573 8.9 20.4 3.042 0.826 PHA 2 Nov 2000 Arecibo & Goldstone 2002 BM26 1.832 0.444 16.2 19.8 2.645 1.019 PHA 5 Feb 2002 Arecibo 2002 KK8 1.967 0.469 24.6 20.5 2.889 1.045 PHA 6 Jun 2002 Arecibo 2003 SS84 1.932 0.572 5.5 21.7 3.037 0.827 PHA 9 Sep 2003 Arecibo & Goldstone 2004 DC 1.634 0.400 19.4 18.0 2.288 0.981 PHA 20 Jun 2006 Arecibo & Goldstone 2005 AB 3.217 0.656 8.2 17.3 5.325 1.107 16 Feb 2005 Arecibo 2005 NB7 2.042 0.516 12.7 18.7 3.096 0.988 PHA 24 Apr 2008 Arecibo & Goldstone 2006 GY2 1.853 0.494 30.6 18.7 2.768 0.938 PHA 19 May 2006 Arecibo & Goldstone 2006 VV2 2.388 0.602 23.6 16.6 3.826 0.949 PHA 21 Mar 2007 Goldstone & Arecibo 2007 DT103 2.210 0.574 5.4 19.5 3.480 0.941 PHA 22 Jul 2007 Goldstone 2008 BT18 2.222 0.598 8.1 18.2 3.551 0.894 PHA 25 Jul 2008 Arecibo
CONFIRMED BINARY NEAS _NOT_ OBSERVED BY RADAR 3671 Dionysus 7088 Ishtar 31345 1998 PG 88710 2001 SL9 137170 1999 HF1 1994 AW1
BINARY AND TERNARY NEAS RANKED BY ABSOLUTE MAGNITUDE Spectral Dprimary Asteroid H Class (km) 1866 Sisyphus 1972 XA 13.0 S ~8 RADAR DISCOVERY 137170 1999 HF1 14.4 X 164121 2003 YT1 16.1 V 1.0 RADAR DISCOVERY 1862 Apollo 1932 HA 16.2 Q 1.5 RADAR DISCOVERY 3671 Dionysus 1984 KD 16.3 C 5381 Sekhmet 1991 JY 16.5 V 1.0 RADAR DISCOVERY 66391 1999 KW4 16.5 S 1.5 RADAR DISCOVERY 7088 Ishtar 1992 AA 16.7 276049 2002 CE26 16.8 C 3.5 RADAR DISCOVERY 2006 VV2 16.8 S 1.8 RADAR DISCOVERY 35107 1991 VH 16.9 S RADAR 153591 2001 SN263 16.9 B RADAR DISCOVERY 1994 AW1 17.3 S 31345 1998 PG 17.3 Q 88710 2001 SL9 17.4 Q 69230 Hermes 1937 UB 17.5 S 0.6 RADAR DISCOVERY 2005 AB 17.5 C RADAR 136617 1994 CC 17.6 Q 0.7 RADAR DISCOVERY 66063 1998 RO1 17.9 S 0.6 RADAR 65803 Didymos 1996 GT 18.0 S 0.8 RADAR 2004 DC 18.0 0.3 RADAR DISCOVERY 185851 2000 DP107 18.1 X 0.8 RADAR DISCOVERY 175706 1996 FG3 18.2 C 1.8 RADAR 2008 BT18 18.2 S RADAR 85938 1999 DJ4 18.5 Q 0.42 RADAR 2006 GY2 18.7 0.45 RADAR DISCOVERY 2005 NB7 18.8 S 0.5 RADAR DISCOVERY 2000 CO101 19.1 Xk 0.7 RADAR DISCOVERY 1994 XD 19.1 0.6 RADAR DISCOVERY 2007 DT103 19.2 S ~0.3 RADAR DISCOVERY 162000 1990 OS 19.3 0.3 RADAR DISCOVERY 1998 ST27 19.5 C 0.8 RADAR DISCOVERY 2002 BM26 20.1 P 0.6 RADAR DISCOVERY 2000 UG11 20.3 S 0.23 RADAR DISCOVERY 2002 KK8 20.4 0.5 RADAR DISCOVERY 2003 SS84 21.8 0.12 RADAR DISCOVERY Here C includes C and B types and S includes S and Q types Note: absolute magnitudes are taken from Horizons. Values may differ by up to a few tenths of a magnitude from those listed on the Minor Planet Center's websites. Dprimary = diameter of the primary, as estimated from radar observations and/or shape modeling.
Spectral classes (all binaries and triples, not just radar detections): C XXXXX X E M P X S XXXXX XXXXX XXXXX XX V XX X XXX ? XXXXX XX
Abundance of Radar Binaries and Ternaries by Absolute Magnitude: Fraction of Radar Radar radar Fraction of H range NEAs binaries detections known binaries ------- ----- -------- ---------- -------------- H < 13.0 2 0 0.00 None known 13.0 <= H < 14.0 3 1 0.33 1/1 = 1.00 14.0 <= H < 15.0 8 0 0.00 0/1 = 0.00 15.0 <= H < 16.0 15 0 0.00 None known 16.0 <= H < 17.0 29 9 0.31 9/11 = 0.82 17.0 <= H < 18.0 41 3 0.073 3/6 = 0.50 18.0 <= H < 19.0 36 8 0.22 8/9 = 0.89 19.0 <= H < 20.0 37 5 0.14 5/5 = 1.00 20.0 <= H < 21.0 34 3 0.088 3/3 = 1.00 21.0 <= H < 22.0 20 1 0.050 1/1 = 1.00 22.0 <= H 47 0 0.00 None known Table last updated: 2010 Dec 10 (this needs to be updated)
DELTA-V RANKINGS ================ Delta-v rankings for all NEA binaries and ternaries observed with radar and photometry. Not included; 2004 RZ164, a possible binary reported by Kwiatkowski et al., Astron. Astrophys. 462, 341-344 (2007) 2000 PJ5, a possible binary reported by Polishook and Brosch, Icarus 194, 111-124 (2008) 2009 KD5, a possible binary reported by Foster et al. Bull. Am. Astron. Soc. 42, 1055 (2010) [abstract] Number of NEAs in the MPC database = 8424 (2011 Dec 31) RADAR BINARY = Binary or ternary observed by radar, but not necessarily discovered by radar BINARY = Binary observed photometrically but not (yet) by radar SPACECRAFT RENDEZVOUS --------------------- DELTA-V (ASTEROID)/ PROVISIONAL DELTA-V DELTA-V FOR RANK PERCENTILE ASTEROID NAME DESIGNATION (KM/S) THE MOON MARS H (mag) a (AU) e i (deg) ==== ========== ============= =========== ======= ======== ==== ======= ====== === ====== 428 94.95 (65803) Didymos 1996 GT 5.098 0.850 0.809 18.0 1.644 0.384 3.4 RADAR BINARY 666 92.15 (136617) 1994 CC 5.379 0.896 0.854 17.7 1.638 0.417 4.7 RADAR BINARY 1029 87.87 (162000) 1990 OS 5.685 0.947 0.902 19.3 1.678 0.463 1.1 RADAR BINARY 1402 83.47 (153591) 2001 SN263 5.963 0.994 0.947 16.5 1.987 0.478 6.7 RADAR BINARY 1411 83.36 (185851) 2000 DP107 5.966 0.994 0.947 18.2 1.366 0.377 8.7 RADAR BINARY 1549 81.74 (85938) 1999 DJ4 6.053 1.009 0.961 18.6 1.852 0.484 9.2 RADAR BINARY 2174 74.37 2007 DT103 6.354 1.059 1.009 19.2 2.208 0.574 5.4 RADAR BINARY 2195 74.12 (35107) 1991 VH 6.364 1.061 1.010 16.9 1.137 0.144 13.9 RADAR BINARY 2557 69.85 2005 NB7 6.517 1.086 1.034 18.7 2.044 0.518 12.7 RADAR BINARY 2800 66.99 (175706) 1996 FG3 6.609 1.102 1.049 18.4 1.054 0.350 2.0 RADAR BINARY 2868 66.18 2003 SS84 6.635 1.106 1.053 21.8 1.930 0.571 5.5 RADAR BINARY 2946 65.26 (31345) 1998 PG 6.666 1.111 1.058 17.3 2.016 0.391 6.5 BINARY 3013 64.47 (7088) Ishtar 1992 AA 6.691 1.115 1.062 16.7 1.981 0.390 8.3 BINARY 3150 62.86 2008 BT18 6.742 1.124 1.070 18.3 2.218 0.596 8.1 RADAR BINARY 3154 62.81 (3671) Dionysus 1984 KD 6.744 1.124 1.071 16.4 2.197 0.542 13.5 BINARY 3163 62.70 2002 BM26 6.747 1.124 1.071 20.1 1.833 0.444 16.2 RADAR BINARY 3494 58.80 2000 UG11 6.876 1.146 1.091 20.4 1.929 0.573 8.9 RADAR BINARY 4169 50.84 (311066) 2004 DC 7.168 1.195 1.138 18.1 1.634 0.400 19.5 RADAR BINARY 4243 49.97 2000 CO101 7.218 1.203 1.146 19.1 1.076 0.090 15.3 RADAR BINARY 4647 45.21 2005 AB 7.469 1.245 1.186 17.5 3.219 0.655 8.2 RADAR BINARY 4649 45.18 (1862) Apollo 1932 HA 7.471 1.245 1.186 16.2 1.470 0.560 6.4 RADAR BINARY 5089 40.00 (69230) Hermes 1937 UB 7.777 1.296 1.234 17.5 1.655 0.624 6.1 RADAR BINARY 5393 36.41 1994 XD 8.056 1.343 1.279 19.1 2.350 0.733 4.3 RADAR BINARY 5802 31.59 2002 KK8 8.477 1.413 1.346 21.0 1.953 0.466 24.5 RADAR BINARY 5946 29.89 2006 VV2 8.640 1.440 1.371 16.8 2.387 0.605 23.7 RADAR BINARY 6504 23.31 (88710) 2001 SL9 9.322 1.554 1.480 17.6 1.061 0.270 21.9 BINARY 6866 19.04 2006 GY2 9.871 1.645 1.567 18.8 1.859 0.495 30.6 RADAR BINARY 7047 16.91 1994 AW1 10.252 1.709 1.627 17.5 1.105 0.075 24.1 BINARY 7852 7.42 (1866) Sisyphus 1972 XA 12.834 2.139 2.037 12.4 1.894 0.539 41.2 RADAR BINARY 7861 7.31 1998 ST27 12.905 2.151 2.048 19.5 0.819 0.530 21.1 RADAR BINARY 7884 7.04 (137170) 1999 HF1 13.032 2.172 2.069 14.5 0.819 0.462 25.7 BINARY 8052 5.06 (276049) 2002 CE26 14.086 2.348 2.236 16.8 2.233 0.560 47.3 RADAR BINARY 8297 2.17 (164121) 2003 YT1 16.470 2.745 2.614 16.2 1.110 0.292 44.1 RADAR BINARY 8396 1.00 (5381) Sekhmet 1991 JY 18.892 3.149 2.999 16.5 0.947 0.296 49.0 RADAR BINARY 8413 0.80 (66063) 1998 RO1 19.402 3.234 3.080 18.1 0.991 0.720 22.7 RADAR BINARY 8454 0.32 (66391) 1999 KW4 21.300 3.550 3.381 16.5 0.642 0.688 38.9 RADAR BINARY SPACECRAFT FLYBY ---------------- Provisional Delta-v H a e i Rank Percentile Asteroid number and name Designation (km/s) (mag) (AU) (deg) ==== ========== ======================== =========== ======= ===== ===== ===== ===== 257 96.97 (175706) 1996 FG3 4.020 18.4 1.054 0.350 2.0 RADAR BINARY 887 89.54 (35107) 1991 VH 4.499 16.9 1.137 0.144 13.9 RADAR BINARY 916 89.20 2000 CO101 4.514 19.1 1.076 0.090 15.3 RADAR BINARY 1357 84.00 (185851) 2000 DP107 4.775 18.2 1.366 0.377 8.7 RADAR BINARY 1708 79.86 (65803) Didymos 1996 GT 4.998 18.0 1.644 0.384 3.4 RADAR BINARY 1854 78.14 (136617) 1994 CC 5.080 17.7 1.638 0.417 4.7 RADAR BINARY 1944 77.08 (1862) Apollo 1932 HA 5.113 16.2 1.470 0.560 6.4 RADAR BINARY 2004 76.37 (162000) 1990 OS 5.145 19.3 1.678 0.463 1.1 RADAR BINARY 2531 70.16 (88710) 2001 SL9 5.400 17.6 1.061 0.270 21.9 BINARY 2722 67.90 (69230) Hermes 1937 UB 5.481 17.5 1.655 0.624 6.1 RADAR BINARY 2844 66.47 1994 AW1 5.526 17.5 1.105 0.075 24.1 BINARY 3034 64.23 (31345) 1998 PG 5.599 17.3 2.016 0.391 6.5 BINARY 3154 62.81 (7088) Ishtar 1992 AA 5.641 16.7 1.981 0.390 8.3 BINARY 3281 61.31 (85938) 1999 DJ4 5.687 18.6 1.852 0.484 9.2 RADAR BINARY 3367 60.30 (153591) 2001 SN263 5.719 16.5 1.987 0.478 6.7 RADAR BINARY 3452 59.30 2003 SS84 5.748 21.8 1.930 0.571 5.5 RADAR BINARY 3994 52.91 2000 UG11 5.907 20.4 1.929 0.573 8.9 RADAR BINARY 4535 46.53 2007 DT103 6.067 19.2 2.208 0.574 5.4 RADAR BINARY 4812 43.26 2002 BM26 6.154 20.1 1.833 0.444 16.2 RADAR BINARY 4850 42.81 (311066) 2004 DC 6.166 18.1 1.634 0.400 19.5 RADAR BINARY 4998 41.07 2005 NB7 6.218 18.7 2.044 0.518 12.7 RADAR BINARY 5023 40.77 2008 BT18 6.225 18.3 2.218 0.596 8.1 RADAR BINARY 5496 35.20 1994 XD 6.392 19.1 2.350 0.733 4.3 RADAR BINARY 5738 32.34 (3671) Dionysus 1984 KD 6.488 16.4 2.197 0.542 13.5 BINARY 6493 23.44 (137170) 1999 HF1 6.886 14.5 0.819 0.462 25.7 BINARY 6732 20.62 2005 AB 7.100 17.5 3.219 0.655 8.2 RADAR BINARY 6826 19.51 1998 ST27 7.180 19.5 0.819 0.530 21.1 RADAR BINARY 6980 17.70 2002 KK8 7.333 21.0 1.953 0.466 24.5 RADAR BINARY 7379 12.99 (66391) 1999 KW4 7.877 16.5 0.642 0.688 38.9 RADAR BINARY 7387 12.90 2006 VV2 7.883 16.8 2.387 0.605 23.7 RADAR BINARY 7578 10.65 2006 GY2 8.185 18.8 1.859 0.495 30.6 RADAR BINARY 7947 6.30 (164121) 2003 YT1 9.168 16.2 1.110 0.292 44.1 RADAR BINARY 8168 3.69 (1866) Sisyphus 1972 XA 10.189 12.4 1.894 0.539 41.2 RADAR BINARY 8244 2.79 (5381) Sekhmet 1991 JY 10.775 16.5 0.947 0.296 49.0 RADAR BINARY 8328 1.80 (276049) 2002 CE26 11.804 16.8 2.233 0.560 47.3 RADAR BINARY 8479 0.02 (66063) 1998 RO1 18.576 18.1 0.991 0.720 22.7 RADAR BINARY TISSERAND PARAMETER RANKINGS FOR BINARIES Tisserand Parameter is computed from T = aj/a + 2.0*cos(i)*sqrt((a/aj)*(1.0 - e*e)) where aj is the semimajor axis of Jupiter, a is the semimajor axis of an asteroid, i is the asteroid's inclination, and e is the asteroid's eccentricity. In general, most Jupiter-family (short period) comets have T < 3.0 and ~90% of numbered asteroids with a < 3.3 AU have T > 3. PROVISIONAL TISSERAND RANK PERCENTILE ASTEROID NAME DESIGNATION PARAMETER H (mag) a (AU) e i (deg) Q (AU) q (AU) ==== ========== ============= =========== ========= ======= ====== = ======= ====== ====== 196 97.69 2005 AB 2.793 17.5 3.219 0.655 8.2 5.327 1.111 RADAR BINARY 795 90.63 (276049) 2002 CE26 3.066 16.8 2.233 0.560 47.3 3.483 0.983 RADAR BINARY 1034 87.81 1994 XD 3.126 19.1 2.350 0.733 4.3 4.073 0.627 RADAR BINARY 1203 85.82 2006 VV2 3.167 16.8 2.387 0.605 23.7 3.831 0.943 RADAR BINARY 2143 74.73 2008 BT18 3.384 18.3 2.218 0.596 8.1 3.540 0.896 RADAR BINARY 2316 72.69 2007 DT103 3.418 19.2 2.208 0.574 5.4 3.475 0.941 RADAR BINARY 2357 72.21 (3671) Dionysus 1984 KD 3.430 16.4 2.197 0.542 13.5 3.388 1.006 BINARY 2705 68.11 (1866) Sisyphus 1972 XA 3.512 12.4 1.894 0.539 41.2 2.915 0.873 RADAR BINARY 3084 63.64 2005 NB7 3.591 18.7 2.044 0.518 12.7 3.103 0.985 RADAR BINARY 3319 60.87 2002 KK8 3.650 21.0 1.953 0.466 24.5 2.863 1.043 RADAR BINARY 3440 59.44 2000 UG11 3.683 20.4 1.929 0.573 8.9 3.034 0.824 RADAR BINARY 3480 58.97 2003 SS84 3.691 21.8 1.930 0.571 5.5 3.032 0.828 RADAR BINARY 3488 58.87 2006 GY2 3.693 18.8 1.859 0.495 30.6 2.779 0.939 RADAR BINARY 3498 58.75 (153591) 2001 SN263 3.697 16.5 1.987 0.478 6.7 2.937 1.037 RADAR BINARY 3572 57.88 (31345) 1998 PG 3.719 17.3 2.016 0.391 6.5 2.804 1.228 BINARY 3658 56.87 (7088) Ishtar 1992 AA 3.751 16.7 1.981 0.390 8.3 2.754 1.208 BINARY 3911 53.89 (85938) 1999 DJ4 3.840 18.6 1.852 0.484 9.2 2.748 0.956 RADAR BINARY 3977 53.11 2002 BM26 3.860 20.1 1.833 0.444 16.2 2.647 1.019 RADAR BINARY 4483 47.14 (69230) Hermes 1937 UB 4.020 17.5 1.655 0.624 6.1 2.688 0.622 RADAR BINARY 4734 44.18 (162000) 1990 OS 4.107 19.3 1.678 0.463 1.1 2.455 0.901 RADAR BINARY 4851 42.80 (311066) 2004 DC 4.152 18.1 1.634 0.400 19.5 2.288 0.980 RADAR BINARY 4949 41.65 (136617) 1994 CC 4.193 17.7 1.638 0.417 4.7 2.321 0.955 RADAR BINARY 4968 41.42 (65803) Didymos 1996 GT 4.201 18.0 1.644 0.384 3.4 2.275 1.013 RADAR BINARY 5464 35.57 (1862) Apollo 1932 HA 4.414 16.2 1.470 0.560 6.4 2.293 0.647 RADAR BINARY 6240 26.42 (185851) 2000 DP107 4.747 18.2 1.366 0.377 8.7 1.881 0.851 RADAR BINARY 7159 15.59 (164121) 2003 YT1 5.322 16.2 1.110 0.292 44.1 1.434 0.786 RADAR BINARY 7320 13.69 (35107) 1991 VH 5.474 16.9 1.137 0.144 13.9 1.301 0.973 RADAR BINARY 7399 12.76 1994 AW1 5.547 17.5 1.105 0.075 24.1 1.188 1.022 BINARY 7563 10.82 2000 CO101 5.709 19.1 1.076 0.090 15.3 1.173 0.979 RADAR BINARY 7567 10.78 (88710) 2001 SL9 5.710 17.6 1.061 0.270 21.9 1.347 0.775 BINARY 7626 10.08 (175706) 1996 FG3 5.779 18.4 1.054 0.350 2.0 1.423 0.685 RADAR BINARY 7651 9.79 (66063) 1998 RO1 5.809 18.1 0.991 0.720 22.7 1.705 0.277 RADAR BINARY 7814 7.86 (5381) Sekhmet 1991 JY 6.028 16.5 0.947 0.296 49.0 1.227 0.667 RADAR BINARY 8314 1.97 1998 ST27 6.980 19.5 0.819 0.530 21.1 1.253 0.385 RADAR BINARY 8317 1.93 (137170) 1999 HF1 6.987 14.5 0.819 0.462 25.7 1.197 0.441 BINARY 8470 0.13 (66391) 1999 KW4 8.501 16.5 0.642 0.688 38.9 1.084 0.200 RADAR BINARY
Since completion of the upgrade At Arecibo (Jan. 1999): NEA binaries and ternaries with H < 22.0 (diameters > ~200 meters) detected by radar: 28/185 = 15.1% This does not include 2003 SS84, which is probably < 200 m in diameter. NEA ternaries with H < 22 detected by radar: 2/185 = 1.1% Note: the tabulations below include 1866 Sisyphus but do NOT include: 2004 RZ164, a possible binary reported by Kwiatkowski et al. (2007), or 2000 PJ5, a possible binary reported by Polishook and Brosch (2008). Percentage of all NEA binaries and ternaries discovered by radar: 24/36 = 66.7% (includes Sisyphus) Percentage of all NEA binaries and ternaries discovered photometrically: 12/36 = 33.3% Percentage of all NEA binaries and ternaries detected by radar: 30/36 = 84.4% (includes Sisyphus) Percentage of all NEA binaries and ternaries detected photometrically: 16/36 = 44.4% (Lightcurves of 1998 ST27, Hermes, 2003 YT1, 2002 CE26, Apollo, Sisyphus, and 2000 CO101 do not show evidence for secondaries. The secondaries are probably too small.) Percentage of all NEA binaries and ternaries discovered at Arecibo: 19/36 = 52.8% (includes Sisyphus) Percentage of all NEA binaries and ternaries discovered at Goldstone: 5/36 = 13.9% Percentage of all NEA radar binaries and ternaries detected at Arecibo: 29/30 = 96.7% (includes Sisyphus) Percentage of all NEA radar binaries and ternaries detected at Goldstone: 13/30 = 43.3% Percentage of all NEA binaries and ternaries since January 1999 discovered by radar: 23/30 = 76.7% Percentage of all NEA binaries and ternaries since January 1999 detected by radar: 28/30 = 93.3% Percentage of NEA radar binaries and ternaries that are "Potentially Hazardous:" 24/30 = 80.0% Percentage of NEA binaries and ternaries discovered by radar (including Sisyphus) that were targets-of-opportunity: 13/24 = 54.0% Ternaries: Percentage of NEA ternaries discovered by radar: 2/2 = 100% Percentage of NEA multiple systems deteced by radar that are ternaries: 2/30 = 6.7% This is probably an underestimate due to low SNRs for many of the binary radar detections. This does not include 2002 CE26, a candidate ternary system. Photometry of 1999 KW4 in 1999 showed tentative evidence of mutual events, but the binary status of that object was not discovered until radar observations at Goldstone in 2001. 1998 RO1, Didymos, and 1999 DJ4, were strongly suspected of being binaries based on lightcurves prior to observations by radar. Photometry of 2006 VV2 suggested a binary in mid-March 2007 but not at the level required for an IAU Circular by the Binary Asteroid Photometric Survey. Its binary status became clear on March 27, 2007 based on observations at Goldstone. 1990 OS was first detected by radar in 1990 but was unrecognized as a binary system until November, 2003. 1862 Apollo was first detected by radar in 1980 but was unrecognized as a binary system until November, 2005. August, 2007 update: 1866 Sisyphus was suspected of being a binary in December, 1985 based on a narrow spike in CW data that did not move in frequency with the asteroid's 2.4 hour rotation period. Similar echo power spectra were not seen again with any asteroid until September, 2000 when 2000 DP107 was recognized as a binary based on both CW spectra and delay-Doppler imaging. Due to the narrow spikes observed in most known binaries, we now classify Sisyphus as a binary system. With an estimated diameter of about 8 km, Sisyphus is by far the largest binary NEA known. For additional lists of binary NEAs, their discovery history, and estimated physical properties, see Petr Pravec's website at: http://www.asu.cas.cz/~asteroid/binneas.htm#1 [THAT WEBSITE IS NOW OUTDATED]
FUTURE EARTH APPROACHES WITHIN 0.1 AU THROUGH 2099 FOR BINARY OR TERNARY NEAs This table also includes apparitions sufficiently close to yield detections for some objects even if Delta > 0.1 AU. Date Distance (AU) 1862 Apollo 2021 Dec 0.242 2023 May 0.213 2046 Nov 0.0353 2048 May 0.0498 2080 Nov 0.0980 2082 May 0.0333 1866 Sisyphus NONE Approaches within 0.51 AU in Dec. 2011 but the secondary is probably too small to detect photometrically. Sisyphus radar opportunities: 2011 Dec 0.606 Marginal CW target: daily SNR ~5 2032 Nov 0.470 Weak CW target: daily SNR ~15 2045 Nov 0.304 Coarse resolution imaging opportunity: daily SNR ~100 2058 Nov 0.154 Good imaging opportunity: daily SNR > 1000 2071 Nov 0.116 Good imaging opportunity: daily SNR > 1000 3671 Dionysus 2085 Jun 0.0280 5381 Sekhmet 2014 May 0.310 Weak CW target 2015 May 0.227 CW and coarse ranging 2026 May 0.261 CW and coarse ranging 7088 Ishtar NONE 31345 1998 PG NONE 35107 1991 VH 2020 Feb 0.307 Weak CW target 2025 Aug 0.0781 2026 Jan 0.292 Weak CW target 2048 Aug 0.0897 2065 Aug 0.0445 2088 Aug 0.0453 65803 Didymos 2022 Oct 0.0712 2062 Oct 0.0496 66063 1998 RO1 2076 Sep 0.0975 66391 1999 KW4 2016 May 0.265 Weak CW target 2017 May 0.167 coarse imaging target 2018 May 0.0782 2019 May 0.0346 2020 Jun 0.180 CW and ranging 2036 May 0.0155 2053 May 0.0678 2054 May 0.0457 2071 May 0.0175 2088 May 0.0866 2089 May 0.0238 69230 Hermes 2040 Apr 0.0282 2057 Apr 0.0265 2069 Oct 0.0860 2086 Oct 0.0244 85938 1999 DJ4 2057 Mar 0.0846 2062 May 0.0865 88710 2001 SL9 2014 Apr 0.226 CW target 2026 Apr 0.202 CW & ranging target 136617 1994 CC 2032 Aug 0.111 Coarse-resolution imaging target 2053 Jul 0.0729 2074 Jun 0.0170 2095 Jun 0.0335 137170 1999 HF1 2011 Aug 0.385 Weak CW target 153591 2001 SN263 2022 Feb 0.101 162000 1990 OS 2027 Aug 0.131 2040 Sep 0.0824 2053 Nov 0.0204 2077 Oct 0.0862 (162483 2000 PJ5 2018 Jul 0.194 Possible binary; Polishook & Brosch 2008 2027 Jul 0.183 This object does not approach within 0.1 AU until at least 2100. 2049 Jul 0.176 2071 Jul 0.182 2080 Jul 0.196 2093 Jul 0.198) 164121 2003 YT1 2011 May 0.168 2016 Oct 0.0348 2018 May 0.260 CW and ranging 2023 Nov 0.0594 2025 May 0.337 Weak CW 2066 Apr 0.0675 2073 Apr 0.0113 2085 Nov 0.0401 175706 1996 FG3 2011 Nov 0.101 2022 May 0.0783 2024 Nov 0.180 2035 May 0.106 2037 Nov 0.129 2048 May 0.175 2050 Nov 0.0565 2063 Nov 0.0617 2086 Apr 0.0570 2099 May 0.0661 186851 2000 DP107 2016 Aug 0.179 CW and ranging 2067 Sep 0.0424 2075 Sep 0.0457 276049 2002 CE26 2014 Sep 0.131 Imaging 2024 Sep 0.201 CW and ranging 1994 AW1 2015 Jul 0.0650 2022 Jul 0.112 2023 Jan 0.255 Weak CW 2058 Jul 0.0650 2094 Jul 0.0825 1994 XD 2012 Nov 0.0518 2023 Jun 0.0211 2041 Jun 0.0153 1998 ST27 2021 Oct 0.189 Weak CW target 2024 Oct 0.0238 2027 Oct 0.155 CW and ranging 2047 Oct 0.0752 2050 Oct 0.0920 2073 Oct 0.0338 2096 Oct 0.0444 2000 CO101 2028 Sep 0.0608 2057 Sep 0.0252 2096 Sep 0.0307 2000 UG11 2067 Nov 0.0805 2067 Nov 0.0867 2002 BM26 2069 Jan 0.0940 2002 KK8 2054 Jun 0.0740 2003 SS84 2020 Feb 0.0997 2054 Oct 0.0468 2004 DC 2077 Jun 0.0272 (2004 RZ164 2074 Dec 0.0525 Possible binary; Kwiatkowski et al. 2007) 2005 AB NONE 2005 NB7 2046 Apr 0.0294 2006 GY2 2044 May 0.0291 2006 VV2 2092 Mar 0.134 2129 Mar 0.166 2140 Apr 0.118 2177 Mar 0.0319 2007 DT103 2089 Jul 0.0664 2008 BT18 2072 Feb 0.0182
Binary and Triple NEAs observed by radar: What can we estimate for each? Primary Spectral Object Orbit? Density? Shape? Class PI 1862 Apollo No No Maybe Q Benner 1866 Sisyphus No No No S Benner/Margot 5381 Sekhmet Maybe Maybe Maybe V Nolan 35107 1991 VH Yes Yes Yes S Margot In preparation 65803 Didymos Yes Yes Yes M Benner In preparation 66063 1998 RO1 Yes Yes Yes S Benner 66391 1999 KW4 Yes Yes Yes S Ostro/Benner PUBLISHED (2001 data) 69230 Hermes Yes Yes Yes S Margot In preparation 89538 1999 DJ4 Maybe Maybe Yes Q Benner In preparation 136617 1994 CC Yes Yes Yes ? Brozovic PUBLISHED 153591 2001 SN263 Yes Yes Yes P Nolan In preparation 162000 1990 OS Yes Yes Yes ? Benner 164121 2003 YT1 Yes Yes Yes V Nolan 175706 1996 FG3 Yes Yes Yes C Benner 185851 2000 DP107 Yes Yes Yes X Margot PUBLISHED (2000 data); 2008 data in preparation 1994 XD No No No ? Benner 1998 ST27 Yes Yes:Not unique Yes C Benner In preparation 2000 CO101 Not yet Not yet Yes Xk Benner In preparation 2000 UG11 Yes Yes Yes S Nolan/Benner In preparation 2002 BM26 P Nolan 2002 CE26 Yes Yes Yes C Shepard PUBLISHED 2002 KK8 ? Nolan 2003 SS84 Maybe Maybe Yes ? Nolan/Benner 2004 DC Yes Yes Yes ? Taylor In preparation 2005 AB No No No C Benner 2005 NB7 Maybe Maybe Maybe S Shepard 2006 GY2 Yes Yes Yes ? Nolan/Benner 2006 VV2 Yes Yes Yes S Benner/Nolan/Black/Busch In preparation 2007 DT103 No No No S Benner 2008 BT18 No No Yes E Benner PI Number L. A. M. Benner 14 M. Brozovic 1 J. L. Margot 3 M. C. Nolan 8 S. J. Ostro 1 M. K. Shepard 2 P. A. Taylor 1
Published peer-reviewed papers on radar observations: Margot, J. L., M. C. Nolan, L. A. M. Benner, S.J. Ostro, R. F. Jurgens, J. D. Giorgini, M. A. Slade, and D. B. Campbell. Binary asteroids in the near-Earth object population. Science 296, 1445-1448. (2002). Shepard, M. K., J. Schlieder, B. Estes, C. Magri, M. C. Nolan, J.-L. Margot, S. J. Bus, E. L. Volquardsen, A. Rivkin, L. A. M. Benner, J. D. Giorgini, S. J. Ostro, and M. W. Busch. Radar, optical, and thermal observations of the binary near-Earth asteroid 2002 CE26. Icarus 184, 198-210 (2006). Ostro, S. J., J.-L. Margot, L. A. M. Benner, J. D. Giorgini, D. J. Scheeres, E. G. Fahnestock, S. B. Broschart, J. Bellerose, M. C. Nolan, C. Magri, P. Pravec, P. Scheirich, R. Rose, R. F. Jurgens, E. M. de Jong, and S. Suzuki. Radar imaging of binary near-Earth asteroid (66391) 1999 KW4. Science 314, 1276-1280 (DOI: 10.1126/science.1133622) (2006). Scheeres, D. J., E. G. Fahnestock, S. J. Ostro, J. L. Margot, L. A. M. Benner, S. B Broschart, J. Bellerose, J. D. Giorgini, M. C. Nolan, C. Magri, P. Pravec, P. Scheirich, R. Rose, R. F. Jurgens, E. M. de Jong, and S. Suzuki. Dynamical configuration of binary near-Earth asteroid (66391) 1999 KW4. Science 314, 1280-1283 (2006) Brozovic, M., L. A. M. Benner, M. C. Nolan, E. S. Howell, P. A. Taylor, C. Magri,, D. J. Scheeres, J. D. Giorgini, J. T. Pollock, P. Pravec, A. Galad, M. W. Busch, J. L. Margot, M. K. Shepard, D. E. Reichart, K. M. Ivarsen, J. B. Haislip, A. P. LaCluyze, J. Jao, M. A. Slade, K. J. Lawrence, and M. D. Hicks. Radar observations and physical modeling of triple near-Earth asteroid (136617) 1994 CC. Icarus 216, 241-256. Reviews of radar observations of binaries: Ostro, S. J., R. S. Hudson, L. A. M. Benner, J. D. Giorgini, C. Magri, J. L. Margot, and M. C. Nolan. Asteroid radar astronomy. In Asteroids III (W. F. Bottke, A. Cellino, P. Paolicchi, and R. P. Binzel, Eds.), Univ. of Arizona Press, Tucson, pp. 151-168. (2002) Merline, W. J., S. J. Weidenschilling, D. D. Durda, J. L. Margot, P. Pravec, and A. D. Storrs. Asteroids do have satellites. In Asteroids III (W. F. Bottke, A. Cellino, P. Paolicchi, and R. P. Binzel, Eds.), Univ. of Arizona Press, Tucson, pp. 289-312. (2002)
NEA Binary and Ternary systems with at least one companion that rotates more rapidly than its orbital period: 7/28 = 25% 35107 1991 VH 136617 1994 CC Outer satellite only 153591 2001 SN263 Outer satellite only 162000 1990 OS 164121 2003 YT1 1998 ST27 2004 DC
CANDIDATE CONTACT BINARY NEAR-EARTH ASTEROIDS OBSERVED BY RADAR Approximate Rotation Asteroid diameter (km) Period (h) Radar reference 4769 Castalia 1.0 4.0 Ostro et al. 1990, Hudson and Ostro 1994 68346 2001 KZ66 1.0 ~6 Nolan et al., unpublished 2005 CR37 1.0 6.5 Benner et al. 2006 2007 VD12 0.5 7.4 Benner et al., unpublished 11066 Sigurd 3.0 8.5 Benner et al., 2004 (DPS abstract) 8567 1996 HW1 2.0 8.8 Benner et al., unpublished 179806 2002 TD66 0.3 9.5 Nolan et al., unpublished 2000 YF29 0.5 <12 Benner et al., unpublished 2002 HK12 0.6 12.7 Nolan et al., unpublished 2063 Bacchus 0.6 15.1 Benner et al. 1999 2002 NY40 0.4 20.0 Nolan et al., unpublished 2003 UV11 ~0.4 ~24? Taylor et al., unpublished 2004 XL14 0.4 ~24 Brozovic et al., unpublished 52387 1993 OM7 1.0 >26 Ostro et al., unpublished 2008 SV11 0.8 32.4 Nolan et al., unpublished 2007 TU24 0.3 ~1-2 days Ostro et al., unpublished 4450 Pan 1.0 2-3 days Nolan et al., unpublished 152664 1998 FW4 ~0.3 ~18 h Brozovic et al., unpublished 4486 Mithra 1.6 67.5 Brozovic et al. 2010 2002 FC 0.7 days Ostro et al., unpublished 2004 RF84 2.4 weeks Benner et al., unpublished