2006 AM4 Planning
Background
2006 AM4 was discovered by the Mount Lemmon Survey (University of Arizona) on January 8, 2006.
It will approach within 0.013 AU (5 lunar distances) on February 1. Its physical properties
are unknown, but its absolute magnitude of 21.8 suggests a diameter within a factor of two of
140 meters.
Update on January 29: Photometry reported by Carl Hergenrother and Mike Hicks indicate that
2006 AM4 is an extremely rapid rotator with a period of about 5 minutes or 12 minutes.
It is among the most rapidly rotating near-Earth asteroids we have ever tried to observe
with radar. In addition, photometric colors reported by Hicks indicate a Q-type taxonomic class.
Goldstone observations are scheduled on January 31.
Mike Nolan and Lynn Carter observed 2006 AM4 at Arecibo on January 29 and are trying to schedule
more observations on other days. The Arecibo echoes suggest that the Goldstone bandwidth will be
about 180 Hz. Nolan and Carter obtained stronger SNRs than expected so this object
should be strong enough to detect at Goldstone even with the rapid rotation.
Due to the proximity of its orbit to Earth and its diameter, 2006 AM4 has been classified as a
"Potentially Hazardous Asteroid" by the Minor Planet Center.
Orbital and Physical Characteristics
orbit type Aten
semimajor axis 0.982 AU
eccentricity 0.649
inclination 21.9°
perihelion distance 0.345 AU
aphelion distance 1.620 AU
absolute magnitude (H) 21.8
diameter 140 m +- a factor of two
rotation period ~5 minutes or perhaps ~12 minutes
pole direction unknown
lightcurve amplitude ~1 magnitude
spectral class Q
Last updated: 2007 January 29
Discovery
M.P.E.C. 2006-A48 Issued 2006 Jan. 9, 12:55 UT
The Minor Planet Electronic Circulars contain information on unusual
minor planets and routine data on comets. They are published
on behalf of Commission 20 of the International Astronomical Union by the
Minor Planet Center, Smithsonian Astrophysical Observatory,
Cambridge, MA 02138, U.S.A.
Supported in part by the Brinson Foundation
Supported in part by the TABASGO Foundation
Prepared using the Tamkin Foundation Computer Network
MPC@CFA.HARVARD.EDU
URL http://cfa-www.harvard.edu/iau/mpc.html ISSN 1523-6714
2006 AM4
Observations:
K06A04M* C2006 01 08.38574 08 47 07.33 +14 56 21.8 20.8 V EA048G96
K06A04M C2006 01 08.39275 08 47 06.00 +14 56 28.1 20.8 V EA048G96
K06A04M C2006 01 08.39976 08 47 04.66 +14 56 34.4 20.8 V EA048G96
K06A04M C2006 01 08.40677 08 47 03.30 +14 56 40.5 20.4 V EA048G96
K06A04M C2006 01 08.47738 08 46 49.66 +14 57 43.6 20.9 V EA048G96
K06A04M C2006 01 08.48640 08 46 47.91 +14 57 51.7 21.0 V EA048G96
K06A04M C2006 01 09.29294 08 44 16.03 +15 10 29.5 EA048291
K06A04M C2006 01 09.29727 08 44 15.13 +15 10 33.5 EA048291
K06A04M C2006 01 09.30129 08 44 14.31 +15 10 37.4 EA048291
Observer details:
291 LPL/Spacewatch II. Observer A. S. Descour. 1.8-m f/2.7 reflector + CCD.
G96 Mt. Lemmon Survey. Observer E. J. Christensen. Measurers E. C. Beshore,
E. J. Christensen, G. J. Garradd, A. D. Grauer, R. E. Hill, R. A. Kowalski,
S. M. Larson, R. H. McNaught. 1.5-m reflector + CCD.
Orbital elements:
2006 AM4 PHA, Earth MOID = 0.0107 AU
Epoch 2006 Mar. 6.0 TT = JDT 2453800.5 MPC
M 327.86646 (2000.0) P Q
n 1.03759155 Peri. 139.13164 -0.12472207 +0.99059961
a 0.9663144 Node 123.63194 -0.92697985 -0.09614694
e 0.6214473 Incl. 3.86931 -0.35376936 -0.09730453
P 0.95 H 21.9 G 0.15 U 9
Residuals in seconds of arc
060108 G96 0.3- 0.1+ 060108 G96 0.2+ 0.2- 060109 291 0.0 0.2+
060108 G96 0.0 0.0 060108 G96 0.1+ 0.1- 060109 291 0.1- 0.1-
060108 G96 0.2+ 0.0 060108 G96 0.1- 0.1+ 060109 291 0.1+ 0.1-
Ephemeris:
2006 AM4 a,e,i = 0.97, 0.62, 4 q = 0.3658
Date TT R. A. (2000) Decl. Delta r Elong. Phase V
2006 01 05 08 56.11 +14 11.5 0.349 1.302 151.8 20.9 21.2
2006 01 15 08 20.39 +17 02.7 0.249 1.230 170.9 7.3 19.9
2006 01 25 07 00.71 +21 51.0 0.173 1.148 159.3 17.7 19.3
2006 02 04 04 34.36 +24 11.4 0.142 1.055 115.6 57.5 19.9
2006 02 14 02 13.75 +18 17.2 0.166 0.950 72.3 98.1 21.4
Timothy B. Spahr (C) Copyright 2006 MPC M.P.E.C. 2006-A48
SNR Calculation
Target Name: 2006 AM4
HMag: 21.8
Diameter: 0.14 km
Period: 0.085 h
------------GOLDSTONE---------- -------------ARECIBO-----------
Max Max
Dat Run UTC Dat Run UTC
Date RA Decl Delta Runs SNR SNR Window Runs SNR SNR Window
2007 1 27 163 14 0.067 257 1 0 5:24-15:11 66 41 5 5:42- 8:18
2007 1 28 165 15 0.055 310 2 0 5:24-15:24 80 98 11 5:42- 8:24
2007 1 29 169 17 0.043 388 7 0 5:30-15:35 100 260 26 5:54- 8:35
2007 1 30 175 21 0.031 514 91 4 5:42-16:11 129 900 79 6:12- 8:54
2007 1 31 189 28 0.021 700 529 20 6:12-17:23 160 4200 330 7:12- 9:41
2007 2 1 230 36 0.014 700 2011 76 8:30-20:23 117 12000 1100 10:30-11:41
2007 2 2 285 25 0.016 700 1164 44 12:35-23:23 202 12000 830 13:24-16:00
2007 2 3 307 12 0.025 567 190 8 14:35-24:23 144 2100 180 14:48-17:18
2007 2 4 316 6 0.036 405 80 4 15:24-24:36 90 460 49 15:35-17:36
2007 2 5 320 3 0.048 311 4 0 15:41-24:41 58 140 18 16:00-17:36
2007 2 6 323 1 0.060 252 2 0 16:00-24:41 37 43 7 16:23-17:30
Arecibo SNRs reflect results from observations on January 29 (Ptx = 670 kW, OCxsec = 7700 m^2).
Goldstone SNRs have been adjusted to include a radar albedo of 0.4 suggested by Arecibo
observations.
Track Assignments
2006 AM4 Goldstone Schedule
UT UT PST AST Duration Round-trip time
DOY Date TX Window TX Window TX Window hh:mm (seconds)
--- ---- --------- --------- --------- ------- ---------
031 Jan 31 0630-1130 2230-0330 Jan 30-31 0230-0730 Jan 31 05:00 18
Uncertainties
From Horizons, 2007 January 10. Solution #12, # obs: 62 (24 days)
Date__(UT)__HR:MN R.A._(J2000.0)_DEC. delta POS_3sigma DOP_S-sig DOP_X-sig RT_delay-sig
2007-Jan-30 00:00 175.33338 20.86481 .031317041987618 57087.8791 2294.55 8206.89 0.261389
2007-Jan-31 00:00 189.71883 27.59885 .020864089818451 85927.6100 1858.93 6648.83 1.053984
2007-Feb-01 00:00 229.79105 35.93534 .013932556241785 117223.514 218.70 782.21 3.923241
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
From Jon Giorgini, 2007 January 10:
The data you forwarded from G96 is consistent with recovery of 2006 AM4.
For new solution #15, with 66 optical measurements spanning 2006-Jan-8
to 2007-Jan-10, formal 3-sigma X-band uncertainties are as shown below:
Date__(UT)__HR:MN POS_3sigma DOP_X-sig RT_delay-sig
2007-Jan-30 00:00 25.7743491 40.17 0.002005
2007-Jan-31 00:00 39.9160728 36.23 0.002325
2007-Feb-01 00:00 65.2857721 18.58 0.002266
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
From Horizons, 2007 January 17, Solution 19 # obs: 79 (2006-2007)
2007-Jan-30 00:00 175.10937 20.94661 .031320978218304 15.1557839 9.87 35.31 0.001909
2007-Jan-31 00:00 189.38015 27.75570 .020849473871107 24.8301261 8.91 31.88 0.002087
2007-Feb-01 00:00 229.48653 36.32790 .013877308859756 46.8498148 4.59 16.42 0.001657
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
From Jon Giorgini, 2007 January 26:
With 103 usuable optical measurements (2006-Jan-8 to 2007-Jan-25),
2006 AM4 solution #25 formal 3-sigma X-band uncertainties were
computed as shown below.
OSOD and nominal predicts have been set-up on stealth. Will
update them if new astrometry significantly changes predicts
prior to the start of the experiment.
Date__(UT)__HR:MN POS_3sigma DOP_X-sig RT_delay-sig
2007-Jan-29 00:00 3.35432270 22.67 0.001547
2007-Jan-30 00:00 5.51287384 22.22 0.001670
2007-Jan-31 00:00 11.8370887 20.22 0.001671
2007-Feb-01 00:00 29.9869351 10.73 0.001005
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
From Jon Giorgini, 2007 January 29:
With 141 optical measurements (2006-Jan-8 to 2007-Jan-28) and the Arecibo
4us delay, new 2006 AM4 solution #29 was computed. Formal 3-sigma S/X-band
uncertainties are as shown below.
Date__(UT)__HR:MN POS_3sigma DOP_S-sig DOP_X-sig RT_delay-sig
2007-Jan-28 00:00 .691769130 3.39 12.12 0.000157
2007-Jan-29 00:00 .963552260 3.38 12.09 0.000034
2007-Jan-30 00:00 1.44584715 3.33 11.91 0.000094
2007-Jan-31 00:00 2.47087129 3.07 10.98 0.000209
Setups
Plans for the January 31 track
-------------------------------
We will start with solution ??.
This object has a very rapid rotation period of only about 5 minutes, so we're going try
a different CW setup from the ones we normally use. The goal is to see a detection
quickly and to resolve the echo.
Possible CW setup
-----------------
TX polarization RCP
RCV polarization LCP
Frequencies: 2
Dwell: 10 seconds
Bandwidth: 20000 Hz
Sampling interval: 500 x 0.1 usec
VME FFT for PSD files: 1024 for 19.53-Hz resolution
The round-trip time during the track will be only about 18 seconds, so this setup will provide one
dwell per run. We will do at least ten minutes of CW. After that what we do depends in part on
the ephemeris. If Arecibo gets more ranging data then we'll go right to 1/8 usec imaging; otherwise
we'll do 10 usec and 11 usec ranging and then imaging.
Possible ranging setups:
---------------------------------------------------------------------------
127 x 64 10-usec single sample
baud 10 usec
code 127
gates 127
PRP 1270 usec
FFT 32 <-- NOTE THE FFT!
CLT ?
ncoh 1
bandwidth 787.4 Hz
resolution 24.6 Hz
TXOFF +200 Hz -> echo will be centered at +8 bins or in bin 32 + 8 = 40
---------------------------------------------------------------------------
127 x 64 11-usec single sample
baud 11 usec
code 127
gates 127
PRP 1397 usec
FFT 32 <-- NOTE THE FFT!
CLT ?
ncoh 1
bandwidth 715.8 Hz
resolution 22.4 Hz
TXOFF +200 Hz --> echo will be centered at +9 bins or in bin 32 + 9 = 41
-------------------------------------------------------------------------
127 x 64 7-usec single sample
------------------------------
baud 7 usec
code 127
gates 127
PRP 889
FFT 64
CLT ??
ncoh 1
bandwidth 1124.9 Hz
resolution 17.6 Hz
TXOFF +60 -> echo would be centered at +3.4 bins w/perfect ephemeris
-------------------------------------------------------------------------
127 x 64 1-usec single sample
------------------------------
baud 1 usec
code 127
gates 127
PRP 127
FFT 64
CLT 4
ncoh 15
bandwidth 525 Hz
resolution 8.2 Hz
TXOFF +100 -> echo would be centered at +12.2 bins or in bin 32 + 12.2 = 44
-------------------------------------------------------------------------------
0.125-usec ranging (left over from the 1992 UY4 observations in August, 2005)
------------------
setup JX1XS001 revised
baud 0.125 usec
code 127
gates 127
FFT 64
ncoh 984
bandwidth 64.016384 Hz
resolution 1.000256 Hz
TXOFF We used 10 Hz, placing COM in cell 32+10=42
Henceforth use 15 Hz, to put COM in 32+15=47
incoh sums 4 looks=> 8 sec/record => expect records per run ~ RTT/8
PFS CLT gate 21
_____________________________________________________________________
POSSIBLE RANGING SETUPS: (code=127, FFT=64, single-pol'n)
These are from JX, w/ max-band (min-acc) options from Ray Jurgens.
Currently configured for 5-sec records.
_______________________________________________________________________
Setup Baud RP 1-acc 1-acc
usec m usec band res acc band res
_______________________________________________________________________
JX1XS110 11.000 1650 1397.0 715.8 11.2 2 358 5.6
JX1XS070 7.000 1050 889.0 1124.9 17.6 3 375 5.9
JX1XS020 2.000 300 254.0 3937.0 61.5 12 328 5.1
4 984 15.4
JX1XS010 1.000 150 127.0 7874.0 123.0 41 192 3.0
8 984 15.4
JX1XS005 0.500 75 63.5 15748.0 246.1 123 128 2.0
15 1050 16.4
JX1XS002 0.250 37.5 31.75 31496.1 492.1 492 64 1.0
30 1050 16.4
JX1XS001 0.125 18.75 15.875 62992.1 984.3 1970 32 0.5
60 1050 16.4
____________________________________________________________________
Instructions
NOTE: Data should be moved to the appropriate subdirectories in
stealth:/export/data0/rosema/2006AM4/raw/
2006 AM4 POINTING:
OSOD and predicts are at Goldstone on stealth:
/export/data3/osod/ops/2006am4/PRDX.OUT.s29
/PUNCH.OUT.s29
/EPH.OUT.s29
and have been copied to:
/export/data0/rosema/2006AM4/support/
POINTING
TX Offsets
Date (UTC) DOY hhmmss RA Dec Macro LHA Dec RTT OSOD
2007 01 31 31 060000 196.0314 30.1541 A 18.5 29
2007 01 31 070000 197.2911 30.5883 A -0.0065 0.0022 18.2
2007 01 31 080000 198.6041 31.0261 AB 17.8
2007 01 31 090000 199.9733 31.4655 B -0.0068 0.0022 17.5
2007 01 31 100000 201.4024 31.9041 BC 17.1
2007 01 31 110000 202.8952 32.3394 C -0.0071 0.0021 16.8
2007 01 31 120000 204.4559 32.7685 C 16.5
PRDX.OUT.s29
TRANSMITTER: STATION #14, RECEIVER: STATION #14
RECEIVER U.T. RANGE DOPPLER LHA DEC RA EL
2007 JAN 31 06:30 18.3475075107 853768.453 274.0614 30.3706 196.655 20.051
2007 JAN 31 06:40 18.2877728249 850651.962 276.3576 30.4430 196.865 21.808
2007 JAN 31 06:50 18.2282585526 847479.278 278.6524 30.5156 197.078 23.574
2007 JAN 31 07:00 18.1689686328 844250.477 280.9456 30.5883 197.291 25.351
2007 JAN 31 07:10 18.1099069939 840965.675 283.2374 30.6611 197.506 27.136
2007 JAN 31 07:20 18.0510775545 837625.033 285.5277 30.7339 197.723 28.930
2007 JAN 31 07:30 17.9924842259 834228.751 287.8165 30.8069 197.941 30.731
2007 JAN 31 07:40 17.9341308959 830777.070 290.1038 30.8799 198.160 32.540
2007 JAN 31 07:50 17.8760214396 827270.268 292.3896 30.9530 198.381 34.355
2007 JAN 31 08:00 17.8181597080 823708.663 294.6738 31.0261 198.604 36.176
2007 JAN 31 08:10 17.7605495336 820092.606 296.9564 31.0993 198.828 38.003
2007 JAN 31 08:20 17.7031947181 816422.486 299.2375 31.1725 199.054 39.835
2007 JAN 31 08:30 17.6460990353 812698.724 301.5169 31.2458 199.281 41.671
2007 JAN 31 08:40 17.5892662307 808921.773 303.7948 31.3190 199.510 43.512
2007 JAN 31 08:50 17.5327000158 805092.119 306.0710 31.3923 199.741 45.356
2007 JAN 31 09:00 17.4764040671 801210.275 308.3456 31.4655 199.973 47.204
2007 JAN 31 09:10 17.4203820224 797276.782 310.6185 31.5388 200.207 49.054
2007 JAN 31 09:20 17.3646374822 793292.210 312.8897 31.6119 200.443 50.908
2007 JAN 31 09:30 17.3091740095 789257.150 315.1593 31.6851 200.680 52.763
2007 JAN 31 09:40 17.2539951169 785172.219 317.4271 31.7582 200.919 54.620
2007 JAN 31 09:50 17.1991042812 781038.054 319.6932 31.8312 201.160 56.478
2007 JAN 31 10:00 17.1445049306 776855.311 321.9576 31.9041 201.402 58.337
2007 JAN 31 10:10 17.0902004432 772624.666 324.2201 31.9770 201.647 60.196
2007 JAN 31 10:20 17.0361941560 768346.812 326.4809 32.0497 201.893 62.056
2007 JAN 31 10:30 16.9824893534 764022.452 328.7399 32.1223 202.141 63.916
2007 JAN 31 10:40 16.9290892666 759652.309 330.9971 32.1948 202.390 65.774
2007 JAN 31 10:50 16.8759970828 755237.112 333.2524 32.2672 202.642 67.631
2007 JAN 31 11:00 16.8232159307 750777.601 335.5058 32.3393 202.895 69.486
2007 JAN 31 11:10 16.7707488938 746274.525 337.7574 32.4114 203.151 71.339
2007 JAN 31 11:20 16.7185989975 741728.638 340.0070 32.4832 203.408 73.187
2007 JAN 31 11:30 16.6667692163 737140.700 342.2548 32.5548 203.667 75.031
2006 AM4 GOLDSTONE MASTERLOG
==============================================================================
RCV TX
setup runs start -stop osod OFFSET Poln Notes
------------------------------------------------------------------------------
January 31
CW 20 kHz, 2 hops, 10 s dwell 20 064610-065827 29 None RCP VME & PFS 512 FFT w/PSD file
10 usec, 127 code ncoh=1 5 071441-071728 29 +200 RCP VME FFT = 32; PFS problem
11 usec, 127 code ncoh=1 10 073815-074433 29 +200 RCP VME FFT = 32; PFS problem
1/8 usec, 127 code ncoh=120 40 081020-083521 31 +100 RCP VME FFT = 64
10 usec, 127 code ncoh=1 4 084447-084656 31 +200 RCP VME FFT = 32; PFS problem
1 usec, 127 code ncoh=15 4 090155-090406 31 +100 RCP VME FFT = 64
1/8 usec, 127 code ncoh=120 15 091357-092305 31 +100 RCP VME FFT = 64
1/8 usec, 127 code nc0h=120 42 092721-095338 33 +100 RCP VME FFT = 128
1/8 usec, 127 code ncoh=120 146 095714-113022 35 +100 RCP VME FFT = 128
==============================================================================
RADAR ASTROMETRY
2007 01 31 07:30:00 R 17.992434 10.0 8560.D6 -14 Benner, L.A.M.
Correction of -50 usec to soln 29 from 10 and 11 usec ranging.
2007 01 31 09:00:00 R 17.476350 1.0 8560.D6 -14 Benner, L.A.M.
Corr'n of -5 us to soln 31 from 10 us and 1 us ranging. 1 usec
echo is one row deep.
2007 01 31 09:30:00 R 17.309119367 0.375 8560.D6 -14 Benner, L.A.M.
Corr'n of -7/8 usec to soln 33 from 1/8 usec imaging. Placed
COM at TE of echo, which is 3 gates deep.
==============================================================================
Dr. Lance A. M. Benner | PHONE: (818) 354-7412
Mail Stop 300-233 | FAX: (818) 354-9476
Jet Propulsion Laboratory | email: lance@reason.jpl.nasa.gov
Pasadena, CA 91109-8099 | Plan: To live long and prosper
http://echo.jpl.nasa.gov/asteroids/2006AM4/html/2006AM4_planning.html
Asteroid Radar Astronomy