Very Small Radar-Detected Near-Earth Asteroids: D < 200 m


Last modified: 2008 April 16

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

Objects with H > 21 (diameters less than about 200 meters):

                Absolute 
	        magnitude       2x vis rng  Diameter (m)  Rotation
      Asteroid  Horizons  MPC   extent (m) pv=0.05 pv=0.2 Period (h) SC/OC       Reference
      --------  --------  ---   ---------- ------- ------ ---------- -----       ---------
      1998 BY7    21.5    21.5      NA       300     150    <1.3      0.4 +/-0.04   9
      1998 KY26   25.5    25.5      30*       48      24     0.178    0.5 +/-0.1    3
      1999 FN19   22.4    22.5     110       190      95   <11        0.22+/-0.01   5
      1999 MN     21.6                                                              7
      1999 NW2    23.1    23.1      NA       150      72    <4.2      0.35+/-0.02   5
      1999 TN13   23.6    23.6      NA       120      57    <1.3                    5
      1999 TY2    23.3    23.3      NA       130      66     0.121                  4, 8 
      2000 EH26   21.2    21.8     120       260     130   <33                      1
      2000 EW70   21.1    21.1     360       360     180   <33                      7
      2000 LF3    21.6    21.6      NA       300     150    <1.0     <0.2           8
54509 YORP        22.3    22.6     120       170      90     0.288    0.29+/-0.02   7, 10
      2000 UK11   25.0    25.3     <60        52      26    ~0.05                   2
      2000 YA     23.7    23.6     120       110      52    <1.3                    1
      2001 AV43   24.3    24.7      NA        72      36                            8
      2001 BF10   22.3    22.6      NA       170      83    <0.4                    6
      2001 CP36   23.7    23.7      90       110      55    slow?    ~1.0           8
      2001 EC16   22.2    22.3     150       200     100    slow     ~0.2           7
      2001 FR85   24.5    24.8       ?        79      40                            8
      2001 JV1    21.3    21.3       ?       320     160   <29                      9
      2001 SP263  25.6    25.8                42      21                            8
      2001 UP     25.7    25.7                44      22                            8
      2001 WM15   25.0    25.0                60      30                            8
      2001 XX4    21.9    22.1               250     130                            8
      2001 YP3    21.9    22.2               250     130                            8
      2002 AA29   24.1    24.3                                        0.25+/-0.08  12
      2002 AV     20.7    21.0               380     190                            9
      2002 FD6    22.3    21.6     110       210     110   ~1 h                     5
      2002 TS69   24.4    24.6                80      40                            8
      2002 TZ66   25.9    25.7                40      20   <1.1       0.0+/-0.16    5
      2003 EP4    23.7    23.9                                                      8
      2003 HM     21.7    22.2                                                      8
      2003 HN16   22.0    22.5                                                      8
      2003 MS2    21.3    21.3     380       330     170   ~6?       ~0.5           5
      2003 QB30   26.3    26.3                33      17                           11
      2003 RU11   25.6    25.6                46      23   fast                     8
      2003 SR84   25.2    26.0                                                      5 
      2003 SS84   21.7    21.8               275     138                            8, 13 BINARY
      2003 TH2    22.8    22.8                                                      6
      2004 AD     24.3    24.3                                                      6
      2004 FY31   21.9    21.9               251     126   very fast                5
      2004 HX53   23.0    23.5                                                      8
      2004 XL14   21.4    21.4                                                     14
      2005 EU2    22.8    23.1    ~300                                              6,5
      2005 FA     25.2    25.2                                                      8
      2005 HB4    24.4    24.4                                                      8
      2005 TD49   26.4    26.5                                                      8
      2005 TU50   21.5    21.5                                                      8
      2005 WA1    21.6    21.5                                                      8
      2005 WK56   22.6    22.6                                                      8
      2005 XA     26.1    26.1                                                      8
      2006 AM4    21.8    21.9                                                      8, 13
      2006 QV89   25.2    25.3                                                      8
      2006 WB     22.8    22.8     150                                             14
      2006 UQ17   21.9    21.9                                                      8
      2007 EH     27.6    27.7                                                      8
      2007 FY20   24.8                                                              6
      6R10DB9     30.2                                                              5
     
N = 57 (57/222) = 25.7% of all radar-detected NEAs)

Percentage of small radar-detected NEAs that are binaries: 1/57 = 2%

Note: NEA satellites < 200 m in diameter are not included.

NA = visible range extent is not available (was not measured).

* = 3-D shape model diameter was used (1998 KY26 only).

Diameters are listed assuming C-type (0.05) and S-type (0.20) optical geometric albedos,
except for 1998 K26, for which a 3-D shape model is available. 

In the rotation period estimates, if rotation periods have not been reported in
the peer-reviewed literature or in personal communications, in most cases 
an optical albedo of 0.05 was assumed and was used to estimate an upper bound 
on the diameter.  That upper bound and the bandwidth were used to estimate 
upper bounds on the rotation periods.  With 1999 NW2, M. Hicks (pers. comm.) 
obtained photometric colors indicating an SQ-type composition, so an optical 
albedo of 0.2 was assumed to estimate the diameter and to constrain the 
rotation period.

The upper bound on the rotation period of 2000 YA from radar observations is
consistent with the periods estimated from photometry by P. Pravec.  Pravec's
period is ambiguous by a factor of two (1.3 h or 0.65 h).

2000 EW70 is included because it has H > 21.0 even though it has a visible range 
extent of about 180 meters.



REFERENCES
----------

1. Benner, L. A. M., M. C. Nolan, J.-L. Margot, J. D. Giorgini, R. S. Hudson, R. F. Jurgens,
     and S. J. Ostro 2001.  Recent radar observations of four near-Earth asteroids.  
     Bull. Am. Astron. Soc. 33, 918. [Abstract]

2. Nolan, M. C., J.-L. Margot, E. S. Howell, L. A. M. Benner, S. J. Ostro, R. F. Jurgens, 
     J. D. Giorgini, and D. B. Campbell 2001.  Radar observations of near-Earth asteroids
     2000 UG11 and 2000 UK11.  Lunar Planet Sci. XXXII, #2055. [Abstract]

3. Ostro, S. J., P. Pravec, L. A. M. Benner, R. S. Hudson, L. Sarounova, M. D. Hicks, D. L. Rabinowitz,
     J. V. Scotti, D. J. Tholen, M. Wolf, R. F. Jurgens, M. L. Thomas, J. D. Giorgini, P. W. Chodas,
     D. K. Yeomans, R. Rose, R. Frye, K. D. Rosema, R. Winkler, and M. A. Slade 1999.  Radar and
     optical observations of asteroid 1998 KY26.  Science 285, 557-559.

4. Pravec, P., C. Hergenrother, R. Whiteley, L. Sarounova, P. Kusnirak, and M. Wolf 2000.
     Fast rotating asteroids 1999 TY2, 1999 SF10, and 1998 WB2.  Icarus 147, 477-486.

5. Benner, L. A. M, et al., unpublished.

6. Howell, E. S., et al., unpublished.

7. Margot, J.-L., et al., unpublished.

8. Nolan, M. C., et al., unpublished.

9. Ostro, S. J., et al., unpublished.

10.Sarounova, L., et al., unpublished.

11.Shepard, M. K., et al., unpublished.

12.Ostro, S. J., J. D. Giorgini, L. A. M. Benner, A. A. Hine, M. C. Nolan, J. L. Margot, P. W.
     Chodas, and C. Veillet 2003.  Radar detection of asteroid 2002 AA29.  Icarus, in press.

13.Nolan, M. C., A. A. Hine, E. S. Howell, L. A. M. Benner 2003 2003 SS84. IAU Circ. No. 8220.

14. Busch, M. W., et al., unpublished.


Lance Benner
Last modified: Thu Dec 14 13:24:39 PST 2006