BINARY NEAR-EARTH ASTEROIDS DETECTED BY RADAR

http://echo.jpl.nasa.gov/~lance/binary.neas.html


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 (needs confirmation)
  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         2002 CE26           2.233   0.559   47.4   16.5   3.481  0.984  Aug 2004   Arecibo              Radar
 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

"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.  

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:" 22/28 = 78.6%


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
185851 2000 DP107      1.365     0.377      8.7    18.2    1.880   0.850  PHA   1   Sep 2000  Goldstone & 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 CE26       2.233     0.559     47.4    16.5    3.481   0.984       15   Aug 2004  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
175706 1996 FG3
       1994 AW1
 
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 

ALL BINARY AND TRIPLE NEAS RANKED BY ABSOLUTE MAGNITUDE 

(This includes objects not yet detected by radar and some probable binaries 
 have not yet been confirmed.)

Number of confirmed NEA binaries (or triples):  37

                                       Spectral Dprim  
   Asteroid                      H      Class    (km)                   
  1866  Sisyphus   1972 XA      13.0       S     ~8     RADAR DISCOVERY

137170             1999 HF1     14.4       X      
  
164121             2003 YT1     16.2       V      1.0   RADAR DISCOVERY
  1862  Apollo     1932 HA      16.3       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
 35107             1991 VH      16.6       S
                   2006 VV2     16.6       S      1.8   RADAR DISCOVERY
  7088  Ishtar     1992 AA      16.7       
 35107             1991 VH      16.7       S            RADAR
                   2002 CE26    16.8       C      3.5   RADAR DISCOVERY
153591             2001 SN263   16.9       B            RADAR DISCOVERY

                   1994 AW1     17.0       S
 31345             1998 PG      17.1       Q
 88710             2001 SL9     17.4       Q
 69230  Hermes     1937 UB      17.5       S      0.6   RADAR DISCOVERY
                  (2000 PJ5     17.5                    Possible binary; Polishook and Brosch 2008, Icarus 194, 111-124)
                   2005 AB      17.5       C            RADAR 
136617             1994 CC      17.7              0.7   RADAR DISCOVERY

 65803  Didymos    1996 GT      18.0       XM     0.8   RADAR
 66063             1998 RO1     18.0       S      0.6   RADAR
185851             2000 DP107   18.0       X      0.8   RADAR DISCOVERY
                   2004 DC      18.0              0.3   RADAR DISCOVERY
175706             1996 FG3     18.2       C
                   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     18.7       S      0.5   RADAR DISCOVERY

                   2000 CO101   19.0       Xk     0.7   RADAR DISCOVERY
                  (2004 RZ164   19.0                    Possible binary; Kwiatkowski et al. 2007, A&A 462, 341-344)
                   1994 XD      19.1              0.6   RADAR DISCOVERY
162000             1990 OS      19.3              0.3   RADAR DISCOVERY
                   2007 DT103   19.5       S     ~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     20.5              0.5   RADAR DISCOVERY

                   2003 SS84    21.8              0.12  RADAR DISCOVERY

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.  Dprim = diameter of the primary,
as estimated from radar observations and/or shape modeling.

The Figures below need to be updated: do not yet include 1991 VH, 1994 CC, or 2000 CO101

  
  


THE TABLE BELOW NEEDS TO BE UPDATED (2005 NB7, 2008 BT18, 1991 VH, 1994 CC, and several non-binaries are not yet included)
(not updated since April, 2008)   Also need to include 2000 CO101.

                   Radar  Radar
    H range        NEAs   binaries  % binaries
    -------        -----  --------  ----------
13.0 <= H < 14.0     3     1          33   (or 0% if we don't count Sisyphus)
14.0 <= H < 15.0     7     0           0
15.0 <= H < 16.0    13     0           0
16.0 <= H < 17.0    21     7          33
17.0 <= H < 18.0    28     2           7
18.0 <= H < 19.0    27     6          22
19.0 <= H < 20.0    26     4          15
20.0 <= H < 21.0    25     3          12
21.0 <= H < 22.0    14     1           7
H >= 22.0           35     0           0

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 

DELTA-V RANKINGS
================

Delta-v rankings for _all_ NEA binaries observed by radar and photometrically.

These lists 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).

Number of NEAs in the MPC database = 6495

RADAR BINARY = Binary 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)
====  ========== =============             ===========  =======   ======== ====   ======= ======  ===   ======
 281   95.67      (65803) Didymos           1996 GT      5.102    0.850   0.810    18.0   1.645  0.384    3.4  RADAR BINARY
 451   93.06     (136617)                   1994 CC      5.379    0.896   0.854    17.7   1.638  0.417    4.7  RADAR BINARY
 708   89.10     (162000)                   1990 OS      5.685    0.947   0.902    19.3   1.678  0.463    1.1  RADAR BINARY
 967   85.11     (153591)                   2001 SN263   5.966    0.994   0.947    16.5   1.988  0.478    6.7  RADAR BINARY
 973   85.02     (185851)                   2000 DP107   5.969    0.995   0.947    18.2   1.365  0.377    8.7  RADAR BINARY
1066   83.59      (85938)                   1999 DJ4     6.041    1.007   0.959    18.6   1.853  0.483    9.2  RADAR BINARY
1539   76.31                                2007 DT103   6.343    1.057   1.007    19.2   2.209  0.573    5.4  RADAR BINARY
1578   75.71      (35107)                   1991 VH      6.364    1.061   1.010    16.9   1.137  0.144   13.9  RADAR BINARY
1841   71.66                                2005 NB7     6.517    1.086   1.034    18.7   2.044  0.518   12.7  RADAR BINARY
2025   68.83     (175706)                   1996 FG3     6.609    1.102   1.049    18.2   1.054  0.350    2.0        BINARY
2052   68.41                                2003 SS84    6.623    1.104   1.051    21.8   1.931  0.570    5.5  RADAR BINARY
2127   67.26      (31345)                   1998 PG      6.656    1.109   1.056    17.3   2.015  0.392    6.5        BINARY
2163   66.70       (7088) Ishtar            1992 AA      6.681    1.114   1.060    16.7   1.980  0.391    8.3        BINARY
2271   65.04                                2002 BM26    6.735    1.123   1.069    20.1   1.832  0.445   16.2  RADAR BINARY
2296   64.66       (3671) Dionysus          1984 KD      6.747    1.125   1.071    16.3   2.198  0.542   13.5        BINARY
2310   64.44                                2008 BT18    6.754    1.126   1.072    18.3   2.217  0.597    8.1  RADAR BINARY
2558   60.62                                2000 UG11    6.877    1.146   1.092    20.4   1.928  0.573    8.9  RADAR BINARY
3043   53.16                                2004 DC      7.140    1.190   1.133    18.1   1.634  0.399   19.4  RADAR BINARY
3152   51.48                                2000 CO101   7.218    1.203   1.146    19.0   1.076  0.090   15.3  RADAR BINARY
3474   46.52                                2005 AB      7.471    1.245   1.186    17.5   3.220  0.655    8.2  RADAR BINARY
3475   46.51       (1862) Apollo            1932 HA      7.471    1.245   1.186    16.2   1.470  0.560    6.4  RADAR BINARY
3818   41.23      (69230) Hermes            1937 UB      7.775    1.296   1.234    17.5   1.656  0.624    6.1  RADAR BINARY
4059   37.52                                1994 XD      8.056    1.343   1.279    19.1   2.350  0.733    4.3  RADAR BINARY
4373   32.68                                2002 KK8     8.489    1.415   1.347    21.0   1.954  0.465   24.5  RADAR BINARY
4491   30.87                                2006 VV2     8.639    1.440   1.371    16.8   2.388  0.605   23.7  RADAR BINARY
4915   24.34      (88710)                   2001 SL9     9.322    1.554   1.480    17.6   1.061  0.270   21.9        BINARY
5192   20.07                                2006 GY2     9.873    1.645   1.567    18.8   1.858  0.495   30.6  RADAR BINARY
5346   17.70                                1994 AW1    10.252    1.709   1.627    17.6   1.105  0.075   24.1        BINARY
5972    8.07       (1866) Sisyphus          1972 XA     12.834    2.139   2.037    13.0   1.894  0.539   41.2  RADAR BINARY
5977    7.99                                1998 ST27   12.905    2.151   2.048    19.5   0.819  0.530   21.1  RADAR BINARY
6000    7.64     (137170)                   1999 HF1    13.032    2.172   2.069    14.5   0.819  0.462   25.7        BINARY
6144    5.42                                2002 CE26   14.082    2.347   2.235    16.8   2.233  0.559   47.3  RADAR BINARY
6350    2.25     (164121)                   2003 YT1    16.470    2.745   2.614    16.2   1.110  0.292   44.1  RADAR BINARY
6432    0.99       (5381) Sekhmet           1991 JY     18.892    3.149   2.999    16.5   0.947  0.296   49.0  RADAR BINARY
6445    0.79      (66063)                   1998 RO1    19.402    3.234   3.080    18.1   0.991  0.720   22.7  RADAR BINARY
6474    0.34      (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)
====  ========== ========================  ===========   ======= =====   =====  =====   =====
 176    97.29   (175706)                   1996 FG3     4.020    18.2   1.054  0.350    2.0         BINARY
 629    90.32    (35107)                   1991 VH      4.499    16.9   1.137  0.144   13.9   RADAR BINARY
 648    90.02                              2000 CO101   4.514    19.0   1.076  0.090   15.3   RADAR BINARY
 961    85.21   (185851)                   2000 DP107   4.774    18.2   1.365  0.377    8.7   RADAR BINARY
1222    81.19    (65803) Didymos           1996 GT      5.000    18.0   1.645  0.384    3.4   RADAR BINARY
1333    79.48   (136617)                   1994 CC      5.080    17.7   1.638  0.417    4.7   RADAR BINARY
1398    78.48     (1862) Apollo            1932 HA      5.113    16.2   1.470  0.560    6.4   RADAR BINARY
1447    77.72   (162000)                   1990 OS      5.145    19.3   1.678  0.463    1.1   RADAR BINARY
1835    71.75    (88710)                   2001 SL9     5.400    17.6   1.061  0.270   21.9         BINARY
1980    69.52    (69230) Hermes            1937 UB      5.482    17.5   1.656  0.624    6.1   RADAR BINARY
2068    68.17                              1994 AW1     5.526    17.6   1.105  0.075   24.1         BINARY
2225    65.75    (31345)                   1998 PG      5.600    17.3   2.015  0.392    6.5         BINARY
2307    64.49     (7088) Ishtar            1992 AA      5.642    16.7   1.980  0.391    8.3         BINARY
2401    63.04    (85938)                   1999 DJ4     5.687    18.6   1.853  0.483    9.2   RADAR BINARY
2470    61.98   (153591)                   2001 SN263   5.720    16.5   1.988  0.478    6.7   RADAR BINARY
2535    60.98                              2003 SS84    5.748    21.8   1.931  0.570    5.5   RADAR BINARY
2952    54.56                              2000 UG11    5.906    20.4   1.928  0.573    8.9   RADAR BINARY
3386    47.88                              2007 DT103   6.066    19.2   2.209  0.573    5.4   RADAR BINARY
3602    44.55                              2004 DC      6.153    18.1   1.634  0.399   19.4   RADAR BINARY
3606    44.49                              2002 BM26    6.154    20.1   1.832  0.445   16.2   RADAR BINARY
3751    42.26                              2005 NB7     6.218    18.7   2.044  0.518   12.7   RADAR BINARY
3771    41.95                              2008 BT18    6.225    18.3   2.217  0.597    8.1   RADAR BINARY
4141    36.25                              1994 XD      6.392    19.1   2.350  0.733    4.3   RADAR BINARY
4326    33.41     (3671) Dionysus          1984 KD      6.489    16.3   2.198  0.542   13.5         BINARY
4926    24.17   (137170)                   1999 HF1     6.886    14.5   0.819  0.462   25.7         BINARY
5110    21.34                              2005 AB      7.101    17.5   3.220  0.655    8.2   RADAR BINARY
5181    20.24                              1998 ST27    7.180    19.5   0.819  0.530   21.1   RADAR BINARY
5303    18.37                              2002 KK8     7.332    21.0   1.954  0.465   24.5   RADAR BINARY
5602    13.76    (66391)                   1999 KW4     7.877    16.5   0.642  0.688   38.9   RADAR BINARY
5609    13.65                              2006 VV2     7.884    16.8   2.388  0.605   23.7   RADAR BINARY
5762    11.30                              2006 GY2     8.184    18.8   1.858  0.495   30.6   RADAR BINARY
6063     6.67   (164121)                   2003 YT1     9.168    16.2   1.110  0.292   44.1   RADAR BINARY
6244     3.88     (1866) Sisyphus          1972 XA     10.189    13.0   1.894  0.539   41.2   RADAR BINARY
6310     2.86     (5381) Sekhmet           1991 JY     10.775    16.5   0.947  0.296   49.0   RADAR BINARY
6373     1.89                              2002 CE26   11.803    16.8   2.233  0.559   47.3   RADAR BINARY
6494     0.03    (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)
====  ========== =============             ===========  =========   ======= ======   =     ======= ====== ======
 146   97.75                                2005 AB      2.792      17.5     3.220  0.655    8.2    5.329   1.111   RADAR BINARY
 604   90.70                                2002 CE26    3.067      16.8     2.233  0.559   47.3    3.481   0.985   RADAR BINARY
 790   87.84                                1994 XD      3.126      19.1     2.350  0.733    4.3    4.073   0.627   RADAR BINARY
 914   85.93                                2006 VV2     3.167      16.8     2.388  0.605   23.7    3.833   0.943   RADAR BINARY
1644   74.69                                2008 BT18    3.384      18.3     2.217  0.597    8.1    3.541   0.893   RADAR BINARY
1786   72.51                                2007 DT103   3.419      19.2     2.209  0.573    5.4    3.475   0.943   RADAR BINARY
1813   72.09       (3671) Dionysus          1984 KD      3.429      16.3     2.198  0.542   13.5    3.389   1.007         BINARY
2100   67.67       (1866) Sisyphus          1972 XA      3.512      13.0     1.894  0.539   41.2    2.915   0.873   RADAR BINARY
2414   62.84                                2005 NB7     3.591      18.7     2.044  0.518   12.7    3.103   0.985   RADAR BINARY
2580   60.28                                2002 KK8     3.650      21.0     1.954  0.465   24.5    2.863   1.045   RADAR BINARY
2685   58.67                                2000 UG11    3.684      20.4     1.928  0.573    8.9    3.033   0.823   RADAR BINARY
2711   58.27                                2003 SS84    3.691      21.8     1.931  0.570    5.5    3.032   0.830   RADAR BINARY
2720   58.13                                2006 GY2     3.694      18.8     1.858  0.495   30.6    2.778   0.938   RADAR BINARY
2721   58.11     (153591)                   2001 SN263   3.696      16.5     1.988  0.478    6.7    2.938   1.038   RADAR BINARY
2784   57.14      (31345)                   1998 PG      3.720      17.3     2.015  0.392    6.5    2.805   1.225         BINARY
2854   56.07       (7088) Ishtar            1992 AA      3.751      16.7     1.980  0.391    8.3    2.754   1.206         BINARY
3051   53.03      (85938)                   1999 DJ4     3.839      18.6     1.853  0.483    9.2    2.748   0.958   RADAR BINARY
3111   52.11                                2002 BM26    3.860      20.1     1.832  0.445   16.2    2.647   1.017   RADAR BINARY
3500   46.12      (69230) Hermes            1937 UB      4.018      17.5     1.656  0.624    6.1    2.689   0.623   RADAR BINARY
3692   43.17     (162000)                   1990 OS      4.107      19.3     1.678  0.463    1.1    2.455   0.901   RADAR BINARY
3775   41.89                                2004 DC      4.153      18.1     1.634  0.399   19.4    2.286   0.982   RADAR BINARY
3851   40.72     (136617)                   1994 CC      4.193      17.7     1.638  0.417    4.7    2.321   0.955   RADAR BINARY
3865   40.50      (65803) Didymos           1996 GT      4.199      18.0     1.645  0.384    3.4    2.277   1.013   RADAR BINARY
4232   34.85       (1862) Apollo            1932 HA      4.414      16.2     1.470  0.560    6.4    2.293   0.647   RADAR BINARY
4821   25.79     (185851)                   2000 DP107   4.749      18.2     1.365  0.377    8.7    1.880   0.850   RADAR BINARY
5503   15.29     (164121)                   2003 YT1     5.322      16.2     1.110  0.292   44.1    1.434   0.786   RADAR BINARY
5619   13.50      (35107)                   1991 VH      5.474      16.9     1.137  0.144   13.9    1.301   0.973   RADAR BINARY
5682   12.53                                1994 AW1     5.547      17.6     1.105  0.075   24.1    1.188   1.022         BINARY
5802   10.68                                2000 CO101   5.709      19.0     1.076  0.090   15.3    1.173   0.979   RADAR BINARY
5805   10.64      (88710)                   2001 SL9     5.710      17.6     1.061  0.270   21.9    1.347   0.775         BINARY
5846   10.01     (175706)                   1996 FG3     5.779      18.2     1.054  0.350    2.0    1.423   0.685         BINARY
5865    9.71      (66063)                   1998 RO1     5.809      18.1     0.991  0.720   22.7    1.705   0.277   RADAR BINARY
5982    7.91       (5381) Sekhmet           1991 JY      6.028      16.5     0.947  0.296   49.0    1.227   0.667   RADAR BINARY
6361    2.08                                1998 ST27    6.980      19.5     0.819  0.530   21.1    1.253   0.385   RADAR BINARY
6363    2.05     (137170)                   1999 HF1     6.987      14.5     0.819  0.462   25.7    1.197   0.441         BINARY
6488    0.12      (66391)                   1999 KW4     8.501      16.5     0.642  0.688   38.9    1.084   0.200   RADAR BINARY

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 

NEA binaries with H < 22.0 (diameters > ~200 meters) detected since January 1, 1999: 27/159 = 17.0%
This does not include 2003 SS84, which is probably < 200 m in diameter.

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 discovered by radar:                    24/36 =  66.7%  (includes Sisyphus)
Percentage of all NEA binaries discovered photometrically:             12/36 =  33.3% 

Percentage of all NEA binaries detected by radar:                      29/36 =  80.6%  (includes Sisyphus)
Percentage of all NEA binaries 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 discovered at Arecibo:                  19/36 =  52.8%  (includes Sisyphus)
Percentage of all NEA binaries discovered at Goldstone:                 5/36 =  13.9%

Percentage of all NEA radar binaries detected at Arecibo:              28/29 =  96.6%  (includes Sisyphus)
Percentage of all NEA radar binaries detected at Goldstone:            13/29 =  44.8%   

Percentage of all NEA binaries since January 1999 discovered by radar: 23/29 =  79.3%  
Percentage of all NEA binaries since January 1999 detected by radar:   27/29 =  93.1%  

Percentage of NEA radar binaries that are "Potentially Hazardous:"     23/29 =  79.3%

Percentage of NEA binaries discovered by radar (including Sisyphus) that were targets-of-opportunity: 12/24 = 50.0% 

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

                    Date       Distance (AU)
  1862 Apollo       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      NONE

  7088 Ishtar       NONE

 31345 1998 PG      NONE

 35107 1991 VH      2025 Aug    0.0781
                    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
1998 RO1 makes many close approaches to Mercury, including one within 0.0054 AU in 2065.

 66391 1999 KW4     2018 May    0.0782
                    2019 May    0.0346
                    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     NONE

136617 1994 CC      2053 Jul    0.0729
                    2074 Jun    0.0170
                    2095 Jun    0.0335 

137170 1999 HF1     NONE

153591 2001 SN263   NONE

162000 1990 OS      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     2016 Oct    0.0348
                    2023 Nov    0.0594
                    2066 Apr    0.0675
                    2073 Apr    0.0113
                    2085 Nov    0.0401

175706 1996 FG3     2022 May    0.0783
                    2050 Nov    0.0565
                    2063 Nov    0.0617
                    2086 Apr    0.0570
                    2099 May    0.0661

186851 2000 DP107   2067 Sep    0.0424
                    2075 Sep    0.0457

       1994 AW1     2015 Jul    0.0650
                    2058 Jul    0.0650
                    2094 Jul    0.0825

       1994 XD      2012 Nov    0.0518
                    2023 Jun    0.0211
                    2041 Jun    0.0153

       1998 ST27    2024 Oct    0.0238 1998 ST27 also makes frequent close approaches to Mercury.
                    2047 Oct    0.0752
                    2050 Oct    0.0920
                    2073 Oct    0.0338
                    2096 Oct    0.0444

       2000 CO101   2009 Sep    0.0458
                    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 CE26    NONE 

       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     NONE
The next time that 2006 VV2 might be detectable with radar is in 2092 (0.14 AU). 
The next approach within 0.1 AU will occur in March, 2177 at 0.032 AU.

       2007 DT103   2089 Jul    0.0664

       2008 BT18    2008 Jul    0.0151
                    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
136617 1994 CC     Yes          Yes             Yes         ?       Brozovic/Nolan
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
185851 2000 DP107  Yes          Yes             Yes         X       Margot                   PUBLISHED (2000 data)
       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
       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   13
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)

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)

======================================================================

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
       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., submitted for publication
       2002 FC      0.7          days         Ostro et al., unpublished
       2004 RF84    2.4          weeks        Benner et al., unpublished

======================================================================

Last update: 2009 November 11