Goldstone Radar Observations Planning: 2008 CD6


Background


2008 CD6
2008 CD6 will approach within 0.01 au (4 lunar distances) on September 13, 2021.
This object was discovered in February of 2008 by the Mt. Lemmon Survey, tracked for a few days, 
and then not observed again until late August of 2021.  

The absolute magnitude of 23.6 suggests a diameter within a factor of two of
about 60 meters, but otherwise nothing is known about its physical properties.

Due to the close approach and our rough estimate of its size, the radar SNRs may be 
strong enough for detailed delay-Doppler imaging.

2008 CD6 will brighten to 16th magnitude during the close approach when it could be 
a good target for photometry and spectroscopy, although sky motion will be rather rapid.


Goldstone Radar Echo from Asteroid 2008 CD6


Echo power spectrum obtained on September 13.


Orbital and Physical Characteristics  
Name                     2008 CD6
Asteroid number          not numbered   
Discoverer               Mt. Lemmon Survey
Discovery date           2008 Feb  7
Orbit type               Apollo         
Close approach distance  0.0103 au       
Close approach distance  4.01 LD         
Close approach date      2021 Sep 13

semimajor axis           1.976 au       
eccentricity             0.595         
inclination              1.1 deg        
Orbital period           2.78 y
perihelion distance      0.7996 au       
aphelion distance        3.152 au
MOID                     0.00236 au      

absolute magnitude (H)   23.7          
diameter                ~0.06 km       
optical albedo           unknown
rotation period          unknown       
lightcurve amplitude     unknown       
spectral class           unknown       
PHA?                     No           

Last update: 2021 September 12


Discovery M.P.E.C.


2008 CD6
https://www.minorplanetcenter.net/mpec/K08/K08C44.html


SNR Calculations

Goldstone SNRs
2008 CD6
2008 CD6:  D = 0.06 km,  P = 0.5 h,  OC albedo = 0.1

DOY start date    window       RA, dec   dist  runs SNR/day SNR/run
253 2021 Sep 10  03:29-12:51   355,  +6  0.028   591    26      1
254 2021 Sep 11  03:38-13:35     2, +11  0.021   851    93      3
255 2021 Sep 12  04:04-15:22    18, +20  0.014  1385   480     14 
256 2021 Sep 13  05:41-19:30    63, +35  0.010  2087  1600     39  Scheduled 0700-1030 UT.  
257 2021 Sep 14  09:25-21:45   113, +30  0.014  1476   470     13 
258 2021 Sep 15  11:17-22:22   131, +23  0.021   933    93      3
259 2021 Sep 16  12:02-22:35   139, +18  0.029   659    26      1

The asteroid will enter the beam about 10 minutes after we start precal.
High elevations won't be a problem during the track.


Track Assignments


DOY    BOA   BOT   EOT   EOA
256    0530  0700  1030  1100  GSSR Ast 2008 CD6

Goldstone tracks:
     UT         UT         PDT               Duration Round-trip     
DOY  Date       TX Window  TX Window         hh:mm    time (sec)  SNR/run  
256  Sep 13     0700-1030  0000-0330 Sep 13   3:30       10        39



Uncertainties

2008 CD6
JPL/Horizons solution 19, # obs: 137 (2008-2021)
2021 Sep 12
 Date__(UT)__HR:MN     R.A._(a-appar)_DEC.            delta POS_3sigma  DOP_X_3sig  RT_delay_3sig
 2021-Sep-11 00:00 *m  358.65761   8.47671 0.02325043350284      1.435        3.73       0.000749
 2021-Sep-12 00:00 *m    9.84561  15.76194 0.01624128069610      4.109        7.30       0.000743
 2021-Sep-13 00:00 *m   36.96133  28.87088 0.01117044650706     12.173 *     42.99       0.000545
 2021-Sep-14 00:00 *m   88.53390  35.02802 0.01109903553909     16.658       63.27       0.000101
 2021-Sep-15 00:00 *m  120.90358  27.15406 0.01608925197735     10.326       29.11       0.000500

Solution 19 Uncertainties at hourly intervals:
 Date__(UT)__HR:MN     R.A._(a-appar)_DEC.            delta POS_3sigma  DOP_X_3sig  RT_delay_3sig
 2021-Sep-13 06:00      48.65873  32.38475 0.01052700936617     14.813       55.45       0.000425
 2021-Sep-13 07:00      50.76849  32.90011 0.01045527332245     15.201       57.09       0.000402
 2021-Sep-13 08:00      52.91440  33.38330 0.01039516912999     15.564       58.58       0.000379
 2021-Sep-13 09:00      55.09264  33.82992 0.01034713999852     15.899       59.93       0.000355
 2021-Sep-13 10:00      57.29930  34.23592 0.01031154733091     16.203       61.15       0.000331
 2021-Sep-13 11:00      59.53035  34.59778 0.01028866094175     16.473       62.24       0.000306



JPL/Horizons solution 17, # obs: 120 (2008-2021)
2021 Sep 9
 Date__(UT)__HR:MN     R.A._(a-appar)_DEC.            delta POS_3sigma  DOP_X_3sig  RT_delay_3sig
 2021-Sep-11 00:00 *m  358.65767   8.47678 0.02325030072319      4.425        5.59       0.001532
 2021-Sep-12 00:00 *m    9.84579  15.76210 0.01624115343485     10.664       22.28       0.001452
 2021-Sep-13 00:00 *m   36.96197  28.87118 0.01117036132841     27.042 *     97.99       0.000952
 2021-Sep-14 00:00 *m   88.53487  35.02800 0.01109905909476     33.083      126.04       0.000365
 2021-Sep-15 00:00 *m  120.90407  27.15393 0.01608934981532     18.982       53.10       0.001168

JPL/Horizons solution 15,  # obs: 93 (2008-2021)
2021 Sep 7
 Date__(UT)__HR:MN     R.A._(a-appar)_DEC.            delta POS_3sigma  DOP_X_3sig  RT_delay_3sig
 2021-Sep-11 00:00 *m  358.65707   8.47626 0.02325106189730     16.817       21.00       0.004606
 2021-Sep-12 00:00 *m    9.84433  15.76104 0.01624183639794     37.279       84.99       0.004211
 2021-Sep-13 00:00 *m   36.95783  28.86948 0.01117073573358     86.416 *    318.64       0.002475
 2021-Sep-14 00:00 *m   88.52958  35.02827 0.01109878467628     97.338      372.14       0.001523
 2021-Sep-15 00:00 *m  120.90173  27.15465 0.01608869072868     52.117      145.13       0.003867


Apparent Magnitudes, Solar Elongations, Lunar Elongations, and Lunar Illumination: 2008 CD6 Optical Circumstances: Date__(UT)__HR:MN R.A._(a-appar)_DEC. delta APmag S-brt S-O-T /r T-O-M/MN_Illu% 2021-Sep-08 00:00 347.43117 0.58879 0.04695555131688 17.646 n.a. 173.6828 /L 166.2/ 1.3469 2021-Sep-09 00:00 349.61772 2.17622 0.03885237205754 17.284 n.a. 172.2504 /L 156.9/ 5.0489 2021-Sep-10 00:00 352.95089 4.57504 0.03090223108606 16.884 n.a. 169.5106 /L 147.4/ 11.1816 2021-Sep-11 00:00 358.58633 8.54352 0.02323483071655 16.448 n.a. 164.0253 /L 140.2/ 19.4359 2021-Sep-12 00:00 9.75490 15.86838 0.01622467599613 16.019 n.a. 152.2195 /L 138.9/ 29.3390 2021-Sep-13 00:00 36.89354 29.06193 0.01115375989985 15.945 n.a. 125.2541 /L 151.8/ 40.3091 * 2021-Sep-14 00:00 88.64698 35.21945 0.01108887563627 17.404 n.a. 82.6937 /L 168.4/ 51.7148 2021-Sep-15 00:00 121.02662 27.25759 0.01608621193344 20. n.a. 55.1812 /L 159.4/ 62.9279 2021-Sep-16 00:00 134.08144 21.19063 0.02306368488925 22. n.a. 42.9429 /L 160.6/ 73.3642 Prospects look excellent for additional astrometry: it's bright, getting brighter, near opposition until after the Goldstone track, and well away from the Moon.

Setups





CW setup:
---------------------------------------------------------------------------
TX polarization           RCP
RCV polarization          LCP & RCP
Frequency hops:           no hopping
Bandwidth:               5000 Hz 
TXoffset                 +500 Hz
FFT                      2500 for 2.0 Hz resolution 

Ranging setups:
---------------------------------------------------------------------------
10-usec
baud             10 usec
code            127
PRP            1270 usec
ncoh              1 
bandwidth       787 Hz   
FFT             128
resolution       6.15 Hz
TXoffset       +100 Hz  (echo in column 80)
---------------------------------------------------------------------------
11-usec 
baud             11 usec
code            127
PRP            1397 usec
ncoh              1 
bandwidth       716 Hz   
FFT             128
resolution      5.6 Hz
TXoffset     +100 Hz  (echo in column 82) 
-------------------------------------------------------------------------
1-usec 
baud              1 usec
code            255
ncoh              8
bandwidth       490 Hz   
FFT             128
resolution        3.8 Hz
TXoffset        +50 Hz  (echo in column 77)
---------------------------------------------------------------------

Possible chirp setups:

chirp at 20 MHz, sample clock at 80 MHz, prp 50 us, offset +50 Hz
downsample     PRP         resolution       range bin count    FFT    ncoh   delta_f
8              50 usec     0.050 usec            1000          256      80    0.98 Hz

chirp at 40 MHz, sample clock at 80 MHz, prp 25 us, offset +50 Hz 
downsample     PRP         resolution       range bin count    FFT    ncoh   delta_f
4              25 usec     0.025  usec           1000          256     160    0.98 Hz



Instructions

NOTE: Data should be moved to the appropriate subdirectories in aardvark:/export/data0/2008cd6/raw/

POINTING:

  OSOD and predicts are on aardvark:



POINTING  

...Not yet available...

Transmit offsets are given in millidegrees.  


PRDX.OUT.14f-14-14.s?? TRANSMITTER: STATION #14, RECEIVER: STATION #14 RECEIVER U.T. RANGE DOPPLER LHA DEC RA EL

2008 CD6 GOLDSTONE MASTERLOG

============================================================================== ----------------------------------------------------- ...Not yet available... -----------------------------------------------------
Dr. Lance A. M. Benner | PHONE: (818) 354-7412 Mail Stop 183-601 | FAX: (818) 393-4445 Jet Propulsion Laboratory | email: lance.benner@jpl.nasa.gov California Institute of Technology | Plan: To live long and prosper Pasadena, CA 91109-8099 https://echo.jpl.nasa.gov/asteroids/2008CD6/2008CD6.2021.goldstone.planning.html

Asteroid Radar Astronomy
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