2013 WT44 Goldstone Radar Observations Planning


Goldstone Radar Images of 2013 WT44


Goldstone radar images of 2013 WT44 with a resolution of 18.75 meters x 0.24 Hz.  Time delay (range) 
increases down and Doppler frequency increases to the right, so the rotation is 
counterclockwise.  

Top: March 20
Sum of 26 runs at 1/8 usec x 0.24 Hz resolution.  The bandwidth is about 6 Hz.  The echo shows
two components whose positions changed very little during ~1 h of imaging.  The appearance of
the echo closely resembles numerous binaries imaged previously with radar.   The cone-shaped
echo from the primary is unlike images we've previously seen from other binary systems,
probably because this one was viewed at a high latitude.

Middle: March 21
Sequence of images that consist of weighted sums of 6 runs each. The images reveal two 
separated objects and establish that 2013 WT44
is a binary system.  The bandwidth on March 21 was 10 Hz, or about 4 Hz wider than on March 20, 
probably indicating that the subradar latitude moved toward the equator betweeen the two days
due to the asteroid's ten degrees of sky motion.   The appearnce of the images on March 21
indicates that the view was still at a high latitude.

Bottom: March 22
Collage of images that were created from weighted sums of six individual runs.  The two objects
clearly  move relative to each other in time delay.  The bandwidth of the primary was about 13 Hz,
strongly suggesting that the subradar latitude moved further toward the equator.  Perhaps due to
a view a lower latitudes, the leading edge is less pointed than on March 20 and 21.  More 
structure is visible along the leading edge of the primary.  


Background


2013 WT44 was discovered by the Catalina Sky Survey (Arizona) on November 27, 2013,
several months before its close encounter within 0.033 AU (13 lunar distances) on March 18.

2013 WT44 has an absolute magnitude of 19.6 that would suggest a diameter of roughly
0.4 km, but with this object there are measurements from NASA's WISE spacecraft that 
indicate the asteroid is substantially larger.
Preliminary results reported by Amy Mainzer (JPL) suggest that 2013 WT44 has
a diameter of 0.9 - 1.1 km and that it's a optically dark.  Consequently,
it's going to be a very good target at Goldstone that we hope will provide
SNRs strong enough for high-resolution imaging with the chirp system.
We do not yet know the rotation period, but it may become available in March
because this object will brighten to 14th magnitude so it will be 
an ideal target for lightcurves (and spectroscopy).

2013 WT44 will approach from the south and we have three short tracks scheduled
on March 20, 21, and 22 to observe it at Goldstone.
Four tracks are also scheduled at Arecibo on March 25, 27, 28, and 29.

2013 WT44 has been classified as a "Potentially Hazardous Asteroid" by the 
Minor Planet Center.

Orbital and Physical Characteristics  
 orbit type               Apollo
 semimajor axis           2.259 AU
 eccentricity             0.568
 inclination              12.2 deg
 perihelion distance      0.975 AU
 aphelion distance        3.542 AU
 absolute magnitude (H)   19.6
 diameter                ~1 km                        (estimated by A. K. Mainzer from WISE data)
 rotation period          unknown but probably relatively fast
 pole direction           unknown...but probably less than 20 deg from (RA, dec) = (178, -21) modulo 180 deg 
 lightcurve amplitude     unknown...apparently low
 spectral class           unknown, but clearly it's optically dark

Last update: 2014 Mar 27

Past and Future Close Approaches Date (CT) Body CA Dist MinDist MaxDist Vrel TCA3Sg Nsigs P_i/p ---------------------- ----- ------- ------- ------- ------ ------ ------ ------- A.D. 1665 Mar 11.32584 Earth .060956 .017723 .141435 10.720 21283. 1.73E5 .000000 A.D. 1726 Mar 19.78567 Earth .023832 .016962 .032191 11.731 2070.7 1.41E5 .000000 A.D. 1726 Sep 22.79270 Hebe .039633 .038727 .041578 15.651 410.50 2.13E5 .000000 A.D. 1821 Jun 07.14212 Juno .017483 .013935 .021778 12.502 298.29 66243. .000000 A.D. 1951 Oct 08.19953 Hygie .048352 .044835 .052060 8.935 168.44 1.55E5 .000000 A.D. 1980 Mar 02.85362 Earth .091709 .081290 .102261 9.747 3459.0 3.20E5 .000000 A.D. 1997 Mar 12.52032 Earth .050083 .045508 .054981 10.428 1522.1 4.94E5 .000000 A.D. 2014 Mar 18.29830 Earth .032740 .032739 .032741 11.130 0.01 65053. .000000 A.D. 2020 Apr 06.39556 Psych .043142 .041554 .044734 11.100 36.20 63172. .000000 A.D. 2031 Mar 23.79162 Earth .067349 .061907 .072926 12.069 1013.9 5.10E5 .000000 A.D. 2133 Mar 22.98178 Earth .020188 .013205 .029153 11.947 2006.9 1.85E5 .000000 A.D. 2150 Mar 27.77070 Earth .062025 .012032 .122619 12.757 9929.0 1.80E5 .000000 The encounter in 2014 is the closest since 1726 and until 2133.

Discovery MPEC

M.P.E.C. 2013-W44                                Issued 2013 Nov. 30, 13:38 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.

             Prepared using the Tamkin Foundation Computer Network

                              MPC@CFA.HARVARD.EDU
            URL http://www.minorplanetcenter.net/    ISSN 1523-6714

                                   2013 WT44

Observations:
     K13W44T* C2013 11 27.27261 04 20 28.61 -10 42 36.1          20.1 VqEW044703
     K13W44T  C2013 11 27.28571 04 20 27.79 -10 42 59.2          19.4 VqEW044703
     K13W44T  C2013 11 27.29227 04 20 27.24 -10 43 11.0          19.4 VqEW044703
     K13W44T KC2013 11 27.58613 04 20 08.20 -10 51 32.7          19.4 VqEW044E23
     K13W44T KC2013 11 27.59655 04 20 07.46 -10 51 51.2          19.2 VqEW044E23
     K13W44T KC2013 11 27.60697 04 20 06.76 -10 52 11.1          19.5 VqEW044E23
     K13W44T |C2013 11 28.16606 04 19 30.65 -11 08 45.2          20.1 VuEW044807
     K13W44T |C2013 11 28.16861 04 19 30.47 -11 08 49.7          19.6 VuEW044807
     K13W44T |C2013 11 28.17118 04 19 30.28 -11 08 54.2          20.0 VuEW044807
     K13W44T |C2013 11 28.17379 04 19 30.09 -11 08 58.7          19.8 VuEW044807
     K13W44T |C2013 11 28.17638 04 19 29.90 -11 09 03.4          19.6 VuEW044807
     K13W44T |C2013 11 29.12084 04 18 27.36 -11 36 57.8          19.4 VuEW044807
     K13W44T |C2013 11 29.12335 04 18 27.18 -11 37 02.2          19.6 VuEW044807
     K13W44T |C2013 11 29.12586 04 18 26.99 -11 37 06.7          19.5 VuEW044807
     K13W44T |C2013 11 29.12838 04 18 26.81 -11 37 11.2          19.9 VuEW044807
     K13W44T |C2013 11 29.13090 04 18 26.62 -11 37 15.7          19.7 VuEW044807
     K13W44T  C2013 11 29.27843004 18 16.36 -11 41 55.0          18.6 RtEW044H01
     K13W44T  C2013 11 29.28843204 18 15.62 -11 42 12.8          18.7 RtEW044H01
     K13W44T  C2013 11 29.30776204 18 14.18 -11 42 47.0          18.6 RtEW044H01
     K13W44T |C2013 11 30.22372 04 17 11.20 -12 09 26.6          19.9 VuEW044807
     K13W44T |C2013 11 30.22622 04 17 11.03 -12 09 31.5          19.6 VuEW044807
     K13W44T |C2013 11 30.22871 04 17 10.84 -12 09 35.9          19.9 VuEW044807
     K13W44T |C2013 11 30.23121 04 17 10.64 -12 09 40.3          19.8 VuEW044807
     K13W44T |C2013 11 30.23371 04 17 10.45 -12 09 44.7          19.6 VuEW044807

Observer details:
703 Catalina Sky Survey.  Observer A. Boattini.  Measurers A. Boattini,
    E. J. Christensen, A. R. Gibbs, A. D. Grauer, R. E. Hill, J. A. Johnson,
    R. A. Kowalski, S. M. Larson, F. C. Shelly.  0.68-m Schmidt + CCD.
807 Cerro Tololo.  Observers T. Linder, R. Holmes.  0.41-m f/11
    Ritchey-Chretien + CCD.
E23 Arcadia.  Observer A. Hidas.  0.35-m Schmidt-Cassegrain + CCD.
H01 Magdalena Ridge Observatory, Socorro.  Observer W. H. Ryan.  2.4-m f/8.9
    reflector + CCD.

Orbital elements:
2013 WT44                                           PHA, Earth MOID = 0.0322 AU
Epoch 2013 Nov. 4.0 TT = JDT 2456600.5                  MPC
M 327.39659              (2000.0)            P               Q
n   0.29318303     Peri.  325.65884     -0.85168744     -0.52394867
a   2.2441067      Node   182.80466     +0.51555738     -0.83419519
e   0.5651038      Incl.   12.16415     +0.09396327     -0.17203541
P   3.36           H   19.2           G   0.15           U   8
Residuals in seconds of arc
131127 703  0.0   0.9-    131128 807  0.3-  0.0     131129 H01  0.1+  0.2+
131127 703  1.4+  0.7-    131128 807  0.3-  0.1+    131129 H01  0.1+  0.1+
131127 703  0.1+  0.8-    131128 807  0.4-  0.0     131129 H01  0.1-  0.1+
131127 E23  0.2-  1.4+    131129 807  0.2-  0.0     131130 807  0.0   0.3+
131127 E23  0.2-  1.4+    131129 807  0.1-  0.0     131130 807  0.3+  0.2-
131127 E23  0.3+  0.0     131129 807  0.2-  0.0     131130 807  0.3+  0.2-
131128 807  0.3-  0.1-    131129 807  0.1-  0.0     131130 807  0.1+  0.2-
131128 807  0.2-  0.1-    131129 807  0.2-  0.0     131130 807  0.1+  0.2-

Ephemeris:
2013 WT44                a,e,i = 2.24, 0.57, 12                  q = 0.9760
Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase     V
2013 10 31    04 34 58.3 +01 32 45   0.7464  1.6585   144.6    20.3    20.7
...
2013 11 15    04 30 44.4 -04 45 32   0.5989  1.5409   151.1    18.1    20.0
...
2013 11 23    04 24 42.4 -08 35 54   0.5374  1.4780   150.1    19.4    19.7
...
2013 11 29    04 18 35.1 -11 33 28   0.4990  1.4310   147.0    22.0    19.5
2013 11 30    04 17 27.0 -12 02 57   0.4932  1.4232   146.3    22.6    19.5
2013 12 01    04 16 17.1 -12 32 17   0.4876  1.4154   145.6    23.2    19.5
...
2013 12 07    04 08 48.5 -15 23 52   0.4571  1.3689   140.4    27.3    19.4
...
2013 12 15    03 58 11.6 -18 52 25   0.4240  1.3080   132.4    33.8    19.3
...
2013 12 30    03 40 17.3 -23 49 52   0.3761  1.1996   116.5    47.2    19.3

A. U. Tomatic                (C) Copyright 2013 MPC           M.P.E.C. 2013-W44

SNR Calculation

2013 WT44
D = 0.9 km
P = 12  h       (a lower bound, J. Pollock, pers. comm.))
OC albedo = 0.1 (a relatively conservative lower bound)
Ptx = 200 kW

w  DOY start date     window        RA, dec   dist  runs       SNR/day   SNR/run
12  77 2014 Mar 18  06:14-07:13   158, -34  0.033     53        470        65
12  78 2014 Mar 19  05:13-09:34   169, -28  0.033    229       1000        71
12  79 2014 Mar 20  04:58-10:52   178, -21  0.035    297       1100        66  Scheduled
12  80 2014 Mar 21  04:51-11:47   186, -15  0.038    323        880        54  Scheduled
12  81 2014 Mar 22  04:47-12:26   191, -10  0.042    325        660        40  Scheduled
12  82 2014 Mar 23  04:45-12:55   196,  -5  0.046    315        470        29
13  84 2014 Mar 24  04:43-13:17   199,  -2  0.051    300        330        21
13  85 2014 Mar 25  04:41-13:34   202,  +1  0.056    282        230        15
13  86 2014 Mar 26  04:39-13:46   205,  +4  0.062    264        160        11
13  87 2014 Mar 27  04:38-13:56   207,  +6  0.068    247        110         8
13  88 2014 Mar 28  04:35-14:03   208,  +8  0.074    231         83         6
13  89 2014 Mar 29  04:33-14:09   210,  +9  0.080    217         61         4
13  90 2014 Mar 30  04:31-14:13   211, +10  0.086    204         45         3
14  91 2014 Mar 31  04:28-14:16   212, +11  0.092    192         35         3

Goldstone SNRs assume Ptx = 200 kW due to a klystron problem


Arecibo SNRs
 start date    window        RA, dec   dist    runs     SNR/day   SNR/run
2014 Mar 25  05:06-06:24    202,  +1  0.056     41       2700       460  Scheduled...but cancelled due to equipment problems
2014 Mar 26  04:57-06:44    204,  +4  0.061     51       2600       400
2014 Mar 27  04:53-06:57    206,  +6  0.067     55       2000       300  Scheduled...but cancelled
2014 Mar 28  04:50-07:05    208,  +7  0.073     55       1500       220  Scheduled...but cancelled
2014 Mar 29  04:48-07:11    210,  +9  0.079     53       1200       170  Scheduled 
2014 Mar 30  04:46-07:15    211, +10  0.085     52        890       130
2014 Mar 31  04:45-07:17    212, +11  0.091     49        680       100
2014 Apr 01  04:43-07:18    213, +12  0.097     47        530        81
2014 Apr 02  04:41-07:19    214, +13  0.104     45        420        65  Overlaps time scheduled for NEA radar survey work
2014 Apr 03  04:39-07:18    214, +14  0.110     43        330        53
2014 Apr 04  04:37-07:18    215, +14  0.117     41        270        43
2014 Apr 05  04:35-07:16    215, +15  0.123     39        210        36
2014 Apr 06  04:32-07:15    216, +15  0.130     37        170        30
2014 Apr 07  04:30-07:13    216, +16  0.136     35        140        25  Overlaps time scheduled for 2004 FG11 (another binary)
2014 Apr 08  04:27-07:10    217, +16  0.143     34        120        21  Overlaps 2004 FG11
2014 Apr 09  04:24-07:08    217, +16  0.150     32         99        18  Overlaps 2004 FG11

Arecibo SNRs assume Ptx = 650 kW.  

Track Assignments


Goldstone tracks:
079 0330 0500 0655 0725  DSS-14  GSSR   AST 2013 WT44          
080 0315 0445 0620 0650  DSS-14  GSSR   AST 2013 WT44          
081 0315 0445 0645 0715  DSS-14  GSSR   AST 2013 WT44          

        UT         UT            PDT                Duration   Round-trip   SNR/  
DOY     Date       TX Window     TX Window            hh:mm    time (sec)   Run 
---     ----       ---------     ---------          ---------  ---------    ----
079     Mar 20     0500-0655     2200-2355 Mar 19      1:55      35          66
080     Mar 21     0450-0620     2150-2320 Mar 20      1:30      38          54
081     Mar 22     0445-0645     2145-2345 Mar 21      2:00      42          40


Arecibo tracks:
084     Mar 25     0506-06254    2206-2354 Mar 24      1:48      56         460  Cancelled due to equipment problems
085     Mar 26     ...No track...
086     Mar 27     0453-0657     2153-2357 Mar 26      2:04      67         300  Cancelled
087     Mar 28     0450-0705     2150-0005 Mar 27-28   2:15      73         220  Cancelled
088     Mar 29     0448-0711     2148-0011 Mar 28-29   2:23      79         170 


Uncertainties

From Jon Giorgini, 2014 Mar 19:

For 2013 WT44, 198 optical measurements 2013-Nov-27 to 2014-Mar-18
were used to estimate orbit solution #35. OSOD with nominal predicts
is now on aardvark in the /2013wt44 sub-directory.

Formal 3-sigma X-band uncertainties for s35:

 Date__(UT)__HR:MN  POS_3sigma   DOP_X_3sig  RT_delay_3sig
 2014-Mar-19 00:00       0.434         3.36       0.001116
 2014-Mar-20 00:00       0.592         6.69       0.001164
 2014-Mar-21 00:00       0.732         9.55       0.001242
 2014-Mar-22 00:00       0.819        11.84       0.001345

- - - - - - - - - - 

JPL/Horizons solution 31, #obs =  155 (2013-2014)

 2014-Mar-15 00:00 *   117.93371 -44.85363 0.03899092381860      1.115        3.03       11.00       0.001683
 2014-Mar-16 00:00 *   129.79418 -43.52216 0.03592471912924      1.445        2.52        9.16       0.001588
 2014-Mar-17 00:00 *   142.59438 -40.53941 0.03380130166828      1.950        2.09        7.60       0.001510
 2014-Mar-18 00:00 *   155.13845 -35.79792 0.03281348377563      2.535        1.91        6.94       0.001452
 2014-Mar-19 00:00 *   166.35669 -29.74986 0.03307214490109      3.045        2.02        7.33       0.001419
 2014-Mar-20 00:00 *   175.74677 -23.21630 0.03455780077408      3.353        2.29        8.33       0.001417
 2014-Mar-21 00:00 *   183.32718 -16.95823 0.03713144747943      3.436        2.67        9.69       0.001451
 2014-Mar-22 00:00 *   189.36703 -11.41525 0.04059421515458      3.351        3.10       11.28       0.001521
 2014-Mar-23 00:00 *   194.18314  -6.71966 0.04474736432198      3.174        3.55       12.89       0.001621
 2014-Mar-24 00:00 *   198.05323  -2.82533 0.04942412836998      2.961        3.96       14.38       0.001745
 2014-Mar-25 00:00 *   201.19606   0.38258 0.05449669513626      2.746        4.31       15.66       0.001889
 2014-Mar-26 00:00 *   203.77690   3.02847 0.05987130333082      2.545        4.60       16.73       0.002048
 2014-Mar-27 00:00 *   205.91905   5.22259 0.06548035450153      2.363        4.85       17.63       0.002218

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

Apparent Magnitudes, Solar Elongations, Lunar Elongations, and Lunar Illumination:

 Date__(UT)__HR:MN     R.A._(a-appar)_DEC.            delta  APmag    S-O-T /r  T-O-M/Illu%
 2014-Mar-15 00:00     117.87093 -44.81195 0.03898367055075  14.93 111.0513 /T   60.7/ 97.0
 2014-Mar-16 00:00     129.72252 -43.48324 0.03591381812921  14.53 118.7897 /T   56.3/ 99.4
 2014-Mar-17 00:00     142.51910 -40.50474 0.03378649001770  14.16 127.7933 /T   50.3/ 99.9
 2014-Mar-18 00:00     155.06631 -35.76719 0.03279490138725  13.83 137.6277 /T   44.0/ 98.3
 2014-Mar-19 00:00     166.29252 -29.72125 0.03305041248414  13.59 147.4685 /T   39.6/ 94.7
 2014-Mar-20 00:00     175.69215 -23.18806 0.03453385732317  13.44 156.2640 /T   39.3/ 89.0
 2014-Mar-21 00:00     183.28146 -16.92964 0.03710624844943  13.40 162.9263 /L   44.1/ 81.5
 2014-Mar-22 00:00     189.32873 -11.38652 0.04056851400624  13.48 166.4433 /L   52.5/ 72.4
 2014-Mar-23 00:00     194.15073  -6.69128 0.04472165968799  13.69 166.6514 /L   62.9/ 62.1
 2014-Mar-24 00:00     198.02542  -2.79778 0.04939871109047  13.98 164.9100 /L   74.3/ 51.0
 2014-Mar-25 00:00     201.17184   0.40900 0.05447171716291  14.27 162.6128 /L   86.3/ 39.6
 2014-Mar-26 00:00     203.75550   3.05360 0.05984683335080  14.55 160.3865 /L   98.6/ 28.6
 2014-Mar-27 00:00     205.89989   5.24638 0.06545641461904  14.81 158.4219 /L  111.0/ 18.7
 2014-Mar-28 00:00     207.69726   7.07761 0.07125184440821  15.05 156.7493 /L  123.2/ 10.4
 2014-Mar-29 00:00     209.21703   8.61860 0.07719802411691  15.27 155.3469 /L  134.9/  4.4
 2014-Mar-30 00:00     210.51206   9.92495 0.08326941053902  15.48 154.1794 /L  145.5/  0.9
 2014-Mar-31 00:00     211.62305  11.03990 0.08944724241231  15.67 153.2111 /L  153.4/  0.1
 2014-Apr-01 00:00     212.58174  11.99719 0.09571761736343  15.84 152.4097 /L  156.3/  1.9
 2014-Apr-02 00:00     213.41317  12.82333 0.10207015983121  16.01 151.7481 /L  152.8/  6.0
 2014-Apr-03 00:00     214.13730  13.53931 0.10849709455542  16.16 151.2030 /L  145.2/ 12.1
 2014-Apr-04 00:00     214.77022  14.16187 0.11499259638383  16.31 150.7554 /L  135.9/ 19.6
 2014-Apr-05 00:00     215.32504  14.70453 0.12155232758802  16.44 150.3891 /L  125.9/ 28.1


Setups


There are hints that this object may have a rotation period longer than 12 hours and a
diameter of about 1 km, so we may see a bandwidth of less than 10 Hz.

CW setup:
---------------------------------------------------------------------------
TX polarization           RCP
RCV polarization          LCP & RCP
Frequency hops:           no hops (+0.5 kHz offset)                  
Bandwidth:                4000 Hz 
Sampling interval:        2500 x 0.1 usec 
PFS FFT:                  4000 for 1.0 Hz res 

Ranging setups:
---------------------------------------------------------------------------
10-usec
baud             10 usec
code            127
PRP            1270 usec
FFT             128   
ncoh              1 
bandwidth       787 Hz   
resolution      6.15 Hz
TXOFF          +100Hz  (echo in bin 64+16=80)
---------------------------------------------------------------------------
11-usec 
baud             11 usec
code            127
PRP            1397 usec
FFT             128  
ncoh              1 
bandwidth       716 Hz   
resolution      5.6 Hz
TXOFF          +100 Hz  (echo in bin 64+18=82) 
-------------------------------------------------------------------------
1-usec 
baud            1 usec
code            127
FFT             512
ncoh             128
bandwidth        61.3 Hz   
resolution       0.12 Hz
TXOFF           +8 Hz -> echo would be centered at 256 + 67=323
-------------------------------------------------------------------------------
0.25-usec ranging 
baud            0.25 usec
code            255
FFT             128
ncoh             16
bandwidth       980  Hz     
resolution       7.7 Hz
TXOFF          +80 Hz -> echo would be centered at 64 + 10 = 74
-------------------------------------------------------------------------------
0.125-usec ranging 
baud            0.125 usec
code            255
FFT             128
ncoh             32
bandwidth       980  Hz     
resolution       7.7 Hz
TXOFF          +80 Hz -> echo would be centered at 64 + 10 = 74


Instructions

POINTING:

  OSOD and predicts are aardvark:

Monostatic with the new waveform generator:
/export/data3/osod/ops/2013wt44/PRDX.OUT.14v-14-14.s??
                              /PUNCH.OUT.14v-14-14.s??
                              /EPH.OUT.s??


POINTING 
                                                       TX Offsets    
Date (UTC)   DOY  hhmmss    RA        Dec      Macro   LHA     Dec  RTT    OSOD

...not available yet...

Transmit offsets are given in millidegrees.  


PRDX.OUT.14f-14-14.s?? ...not available yet...

2013 WT44 GOLDSTONE MASTERLOG

============================================================================== Receive TX Setup hops dwell code ncoh FFT runs start -stop OSOD offset Poln Notes ------------------------------------------------------------------------------
Dr. Lance A. M. Benner | PHONE: (818) 354-7412 Mail Stop 183-610 | 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 http://echo.jpl.nasa.gov/asteroids/2013WT44/2013WT44_planning.html

Asteroid Radar Astronomy
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