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Arecibo and Goldstone Radar Imaging of Contact Binary Near-Earth Asteroids. L. A. M. Benner, M. C. Nolan, J. L. Margot, S. J. Ostro, M. K. Shepard, C. Magri, J. D. Giorgini, and M. W. Busch. Outline. Overview of NEAs detected by radar Updated binary NEA statistics 2005 NB7 (1139) Atami
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Arecibo and Goldstone Radar Imaging of Contact BinaryNear-Earth Asteroids L. A. M. Benner, M. C. Nolan, J. L. Margot, S. J. Ostro, M. K. Shepard, C. Magri, J. D. Giorgini, and M. W. Busch
Outline • Overview of NEAs detected by radar • Updated binary NEA statistics • 2005 NB7 • (1139) Atami • Smorgasbord of contact binaries • Upcoming NEA radar targets • Historical note
Binary NEAs: Statistics for Radar Targets OVERALL Discovered by radar: 21/33 = 64% Detected by radar 25/33 = 76% Discovered at Arecibo: 17/33 = 52% (Includes Sisyphus) Discovered at Goldstone: 4/33 = 12% Since completion of the upgrade at Arecibo in 1999: Discovered by radar: 20/25 = 80% Detected by radar: 23/25 = 92% Abundance among radar targets: 17% Arecibo has become the primary technique for discovery and characterization of binary NEAs.
2000 DP107 2000 2000 UG11 2000 1999 KW4 2001, 2002 1998 ST27 2001, 2004 2002 BM26 2002 2002 KK8 2002 Sekhmet 2003 1998 RO1 2003, 2004 2003 SS84 2003 Hermes 2003 1990 OS 2003 (1990) Didymos 2003 1999 DJ4 2004 2003 YT1 2004 2002 CE26 2004 2005 AB 2005 1994 XD 2005 Apollo 2005 (1980) 2006 GY2 2006 2004 DC 2006 2006 VV2 2007 2007 DT103 2007 2001 SN263 2008 2005 NB7 2008 Binary NEAs Detected by Radar Sisyphus 1985
Contact Binary Candidates Detected by Radar Not included: 3908 Nyx 4179 Toutatis 25143 Itokawa 2201 Oljato (?) 1983 Jun 4769 Castalia 1989 Aug 2064 Bacchus 1996 Mar 4486 Mithra 2000 Jul-Aug 2000 YF29 2001 Jan 2002 FC 2002 Jun 2002 NY40 2002 Aug 141593 2002 HK12 2002 Aug 52387 1993 OM7 2003 Jan 68346 2001 KZ66 2003 Oct 11066 Sigurd 2004 Sep 2005 CR37 2005 Feb 2004 RF84 2005 Feb 2004 XL14 2006 Dec 2007 VD12 2007 Nov 2007 TU24 2008 Jan-Feb 2002 TD66 2008 Feb 4450 Pan 2008 Feb Abundance: ~11% among NEAs > 200 m in diameter
What can we estimate for each? ObjectShape? Class Oljato No S Castalia Available Bacchus Available Q Mithra Maybe 2000 YF29 No S 2002 FC No 2002 NY40 Maybe S 2002 HK12 Maybe X 1993 OM7 No 2001 KZ66 Yes S Sigurd Yes S 2005 CR37 No C? 2004 RF84 No 2004 XL14 Not yet C Returns in December 2007 VD12 No S 2007 TU24 No S 2002 TD66 No S Pan No S
(141593) 2002 HK12Arecibo, Aug. 2002 Aug. 25 Aug. 23
(52387) 1993 OM7Arecibo-Green Bank 2003 Jan 13 2003 Jan 14
(4450) PanArecibo, Feb. 2008 Feb. 13 Feb. 12 Feb. 14
Upcoming Radar Opportunities: 55319 1999 JM8 May-June A 2008 BT18 July A, G 90403 2003 YE45 July A, G 2005 RC34 July A, G 35107 1991 VH August A, G 2000 DP107 September A, G 8567 1996 HW1 September A 137032 1998 UO1 September A 164400 2005 GN59 October A, G 85774 1998 UT18 November A 2004 XL14 December A 2008 EV5 December A, G 2004 LV3 December A 136849 1998 CS1 January A, G
NEA Radar Detection History 40th anniversary of the 1st asteroid radar detection is in June: 1566 Icarus by Dick Goldstein at Goldstone