2011 MD Goldstone Radar Observations Planning
2011 MD was discovered on June 22, 2011 by LINEAR. It will make one of the closest flybys to Earth known on June 27 when it approaches within 0.000125 AU. That's only about 1.9 Earth radii above Earth's surface. 2011 MD has an absolute magnitude of 27.7, suggesting a diameter within a factor of two of 10 meters. Shortly after its discovery, this object appeared on the NASA Near-Earth Object Program risk page and had a cumulative impact probability after 2020 of about 5%. Subsequent astrometry reduced the impact probability by close to a factor of ten and it is very likely that additional astrometry will reduce it even more. This object cannot hit Earth in 2011; even if it did, it would disintegrate harmlessly in the atmosphere. The close approach is attracting media attention: articles have appeared online on skyandtelescope.com, space.com, astronomy.com, spaceweather.com, and on the NASA Near-Earth Object Program website (neo.jpl.nasa.gov). Nothing is known about the physical properties of this asteroid, but it's possible that lightcurves and spectroscopy during June 25-29 will provide its rotation period and spectral class. We have one 5.5 hour track on June 26 to observe this asteroid. The round-trip time will be only two seconds so the observations will be bistatic with reception of echoes at DSS-13. The maser is not available so we will use the HEMT, which has a system temperature of about 80 K. Due to the very short notice, we did not have time to obtain radiation clearance, so we will transmit about 110 kW instead of the usual 450 kW. Even with the lower transmitter power and warm system temperature, this object will be so close that we should still get echoes. We're going to start with CW observations with two hops. What we do next depends on how things go and whether or not we have any equipment problems.
Orbital and Physical Characteristics orbit type Apollo semimajor axis 1.030 AU eccentricity 0.023 inclination 3.2 deg perihelion distance 1.006 AU aphelion distance 1.054 AU absolute magnitude (H) 28.0 diameter ~10 meters +- a factor of two rotation period unknown pole direction unknown lightcurve amplitude unknown spectral class unknown Last update: 2011 Jun 25
M.P.E.C. 2011-M23 Issued 2011 June 23, 11:04 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
2011 MD
Observations:
K11M00D* C2011 06 22.26489 16 52 05.99 +40 34 17.5 18.9 cEM023704
K11M00D C2011 06 22.27521 16 51 58.24 +40 33 54.6 19.2 cEM023704
K11M00D C2011 06 22.29608 16 51 42.63 +40 32 58.8 19.4 cEM023704
K11M00D C2011 06 22.30667 16 51 34.94 +40 32 28.1 19.3 cEM023704
K11M00D KC2011 06 23.07075 16 49 19.28 +39 58 56.4 uEM023J95
K11M00D KC2011 06 23.07233 16 49 18.43 +39 58 48.3 uEM023J95
K11M00D KC2011 06 23.07752 16 49 15.43 +39 58 22.8 18.3 RuEM023J95
K11M00D KC2011 06 23.19989216 50 03.62 +40 02 28.8 18.5 RuEM023H36
K11M00D KC2011 06 23.20205516 50 01.78 +40 02 24.9 18.4 RuEM023H36
K11M00D KC2011 06 23.20428016 49 59.86 +40 02 20.5 18.4 RuEM023H36
K11M00D KC2011 06 23.20646216 49 57.97 +40 02 16.3 18.6 RuEM023H36
K11M00D |C2011 06 23.21662 16 50 09.20 +40 04 30.0 cEM023H06
K11M00D |C2011 06 23.21791 16 50 08.04 +40 04 28.0 cEM023H06
K11M00D |C2011 06 23.21919 16 50 06.85 +40 04 25.5 17.9 RcEM023H06
K11M00D C2011 06 23.26779 16 49 32.80 +40 02 54.0 19.1 RcEM023854
K11M00D C2011 06 23.27072 16 49 30.10 +40 02 47.4 18.7 RcEM023854
K11M00D C2011 06 23.27366 16 49 27.23 +40 02 35.8 19.1 RcEM023854
Observer details:
704 Lincoln Laboratory ETS, New Mexico. Observers M. Blythe, G. Spitz,
R. Brungard, J. Paige, P. Festler, T. McVey, A. Valdivia. 1.0-m f/2.15
reflector + CCD.
854 Sabino Canyon Observatory, Tucson. Observer J. E. McGaha. 0.36-m f/10.0
Schmidt-Cassegrain + CCD.
H06 RAS Observatory, Mayhill. Observer H. Sato. 0.25-m f/3.4 reflector + CCD.
H36 Sandlot Observatory, Scranton. Observer G. Hug. 0.56-m reflector + CCD.
J95 Great Shefford. Observer P. Birtwhistle. 0.40-m f/6.0 Schmidt-Cassegrain
+ CCD.
Orbital elements:
2011 MD Earth MOID = 0.0006 AU
Epoch 2011 Aug. 27.0 TT = JDT 2455800.5 MPC
M 51.54504 (2000.0) P Q
n 0.90091518 Peri. 6.12962 +0.15113548 +0.98754135
a 1.0617284 Node 272.56906 -0.90879587 +0.12137078
e 0.0431456 Incl. 2.51400 -0.38890632 +0.10015593
P 1.09 H 27.7 G 0.15 U 3
Residuals in seconds of arc
110622 704 0.4+ 0.3+ 110623 J95 0.1- 0.0 110623 H06 (0.4+ 3.8+)
110622 704 0.4+ 0.2- 110623 H36 0.7- 0.4+ 110623 H06 (0.1+ 3.2+)
110622 704 0.8- 0.8- 110623 H36 0.5- 0.5+ 110623 854 0.3+ 0.3+
110622 704 0.3- 1.3+ 110623 H36 0.5- 0.4+ 110623 854 0.8+ 1.8+
110623 J95 0.1+ 0.1- 110623 H36 0.6- 0.6+ 110623 854 0.6- 1.3-
110623 J95 0.7+ 0.4- 110623 H06 (0.3+ 4.0+)
Ephemeris:
2011 MD a,e,i = 1.06, 0.04, 3 q = 1.0159
Date TT R. A. (2000) Decl. Delta r Elong. Phase V
...
2011 06 23 16 50 26.8 +40 09 21 0.0057611.0187 114.1 65.6 18.9
2011 06 24.00 16 47 04.1 +39 25 25 0.0046941.0183 114.3 65.4 18.4
2011 06 24.20 16 46 12.3 +39 13 52 0.0044771.0183 114.4 65.4 18.3
2011 06 24.40 16 45 15.3 +39 01 03 0.0042581.0182 114.5 65.3 18.2
2011 06 24.60 16 44 12.4 +38 46 44 0.0040371.0181 114.6 65.2 18.1
2011 06 24.80 16 43 02.6 +38 30 39 0.0038141.0180 114.7 65.1 17.9
2011 06 25.00 16 41 44.5 +38 12 26 0.0035881.0180 114.8 65.0 17.8
2011 06 25.20 16 40 16.6 +37 51 37 0.0033601.0179 114.9 64.9 17.7
2011 06 25.40 16 38 36.7 +37 27 36 0.0031291.0178 115.1 64.8 17.5
2011 06 25.60 16 36 42.0 +36 59 33 0.0028951.0177 115.3 64.6 17.3
2011 06 25.80 16 34 28.6 +36 26 16 0.0026571.0177 115.5 64.3 17.1
2011 06 26.00 16 31 50.9 +35 46 05 0.0024141.0176 115.8 64.1 16.9
2011 06 26.20 16 28 41.1 +34 56 24 0.0021661.0175 116.2 63.7 16.7
2011 06 26.40 16 24 46.6 +33 53 08 0.0019111.0174 116.7 63.2 16.4
2011 06 26.60 16 19 47.1 +32 29 11 0.0016471.0173 117.3 62.7 16.0
2011 06 26.80 16 13 05.4 +30 31 05 0.0013731.0172 118.1 61.9 15.6
2011 06 27.00 16 03 25.0 +27 29 10 0.0010831.0171 119.3 60.7 15.1
2011 06 27.20 15 47 25.7 +21 59 27 0.0007691.0170 121.1 58.9 14.3
2011 06 27.40 15 10 41.5 +07 23 40 0.0004131.0168 123.9 56.1 12.9
2011 06 27.60 03 44 48.2 -21 01 03 0.0001581.0165 58.9 121.1 13.7
2011 06 27.80 01 25 20.1 +33 03 02 0.0005471.0164 65.3 114.7 15.9
2011 06 28.00 00 49 25.3 +41 46 35 0.0008851.0163 70.4 109.5 16.6
2011 06 28.20 00 29 28.3 +45 32 37 0.0011891.0163 73.1 106.9 17.1
2011 06 28.40 00 16 10.6 +47 41 47 0.0014731.0162 74.7 105.2 17.5
2011 06 28.60 00 06 28.7 +49 06 25 0.0017431.0162 76.0 104.0 17.8
2011 06 28.80 23 59 00.2 +50 06 39 0.0020031.0162 76.9 103.0 18.0
2011 06 29.00 23 53 00.9 +50 51 56 0.0022551.0162 77.6 102.3 18.2
2011 06 29.20 23 48 05.0 +51 27 22 0.0025011.0161 78.2 101.6 18.4
...
Gareth V. Williams (C) Copyright 2011 MPC M.P.E.C. 2011-M23
Target Name: 2011 MD
HMag: 27.6
Diameter: 10 meters an educated guess
Period: 0.5 hours an educated guess
# max
2011MD: D = 0.01 km, P = 0.5000 hr, OC albedo = 0.100
Goldstone: G = 0.94 K/Jy, Tsys = 18.0 K, P = 450 kW, elev >= 20.00 deg, unhopped
t_down = 0 s, t_switch = 0 s
# max
start date window RA, dec dist runs SNR SNR/RTT
2011 Jun 25 00:17-12:12 250, +38 0.003 6548 150 2
2011 Jun 26 00:12-11:43 247, +35 0.002 9725 810 9
2011 Jun 27 00:07-09:58 239, +25 0.001 20000 26000 200
2011 Jun 27 17:56-20:16 36, -3 0.000 20000 47000000 38000
2011 Jun 28 07:35-19:57 3, +49 0.001 16766 4800 40
2011 Jun 29 06:18-19:43 354, +53 0.003 9474 430 5
2011 Jun 30 05:46-19:33 351, +54 0.004 6786 110 1
Goldstone SNRs assume Ptx = 115 kW, reception at DSS-13, and Tsys = 80 K
Goldstone track:
UT UT PST Duration Round-trip
DOY Date TX Window TX Window hh:mm time (sec) SNR/Run
--- ---- --------- --------- --------- ------- -------
177 Jun 26 0530-1100 2230-0400 Jun 25-26 5:30 2 9
From Jon Giorgini, 2011 Jun 26
Solution 6
With 137 optical measurements (2011-Jun-22 to 2011-Jun-25),
including 10 measurements from Michael Hicks at Table Mountain
after the DOU (and clean-up of site-biased outlier data),
2011 MD orbit solution #6 was estimated.
Formal 3-sigma uncertainties are shown below. Pointing knowledge
is secure for the radar experiment.
Date__(UT)__HR:MN POS_3sigma DOP_X_3sig RT_delay_3sig
2011-Jun-26 05:30 6.521 61.51 0.001350
2011-Jun-26 06:00 6.932 61.51 0.001351
2011-Jun-26 06:30 7.382 61.53 0.001352
2011-Jun-26 07:00 7.870 61.55 0.001353
2011-Jun-26 07:30 8.394 61.58 0.001355
2011-Jun-26 08:00 8.952 61.61 0.001357
2011-Jun-26 08:30 9.541 61.66 0.001358
2011-Jun-26 09:00 10.158 61.72 0.001360
2011-Jun-26 09:30 10.799 61.79 0.001363
2011-Jun-26 10:00 11.463 61.87 0.001365
2011-Jun-26 10:30 12.145 61.97 0.001368
2011-Jun-26 11:00 12.844 62.09 0.001371
Differencing predictions for orbit solution #6 with the prior solution #2 ...
(at the start of the DSS-14 -> 13 bistatic experiment)
TRANSMITTER: STATION #14, RECEIVER: STATION #13
RECEIVER U.T. RANGE DOPPLER LHA DEC RA EL
s6: 2011 JUN 26 05:30 2.2277441286 122173.137 352.0759 35.1119 247.631 83.524
s2: 2011 JUN 26 05:30 2.2281117647 122152.050 352.0750 35.1127 247.632 83.523
------------ ---------- ------- -------
-0.000367636 s 21.087 Hz RSS of 4.6"
... so there was a +0.2-sigma shift in pointing, a +0.2-sigma shift in Doppler,
and a -0.15-sigma shift in round-trip time, relative to the prior solution.
So orbit s6 is well within the uncertainties of prior orbit solution #2
and, while they aren't totally independent results, indicate statistics
for s6 should be reliable and that we would have been "OK" going with
predictions based on orbit s2.
- - - - - - - - - - - - - - - - -
From Jon Giorgini, 2011 June 24:
With 56 measurements (2011-Jun-22 to 2011-Jun-24), 3-sigma
uncertainties are:
Date__(UT)__HR:MN POS_3sigma DOP_S_3sig DOP_X_3sig RT_delay_3sig
2011-Jun-25 00:00 7.442 76.96 275.28 0.004680
2011-Jun-25 12:00 23.064 79.01 282.61 0.005617
2011-Jun-26 00:00 44.493 84.47 302.14 0.006804
2011-Jun-26 12:00 129.561 99.21 354.85 0.008226
2011-Jun-27 00:00 351.339 155.33 555.57 0.010206
2011-Jun-27 12:00 3416.609 792.35 2833.98 0.013692
2011-Jun-28 00:00 1943.678 423.56 1514.93 0.013759
2011-Jun-28 12:00 589.193 66.27 237.04 0.011918
2011-Jun-29 00:00 540.301 45.96 164.37 0.011751
Differencing s2-s1:
TRANSMITTER: STATION #14, RECEIVER: STATION #14
RECEIVER U.T. RANGE DOPPLER LHA DEC RA EL
s2: 2011 JUN 26 04:10 2.2981224810 127402.057 331.3577 35.2852 248.200 66.722
s1: 2011 JUN 26 04:10 2.1494378465 132398.396 331.6348 34.9606 247.923 66.895
------------ ---------- ------- -------
0.148685 -4996.34 0.3246 0.277
(-2.75 sigma doppler, 3-sigma delay, 3-sigmas pointing)
Considering the short s1 arc (17 measurements, 1 day) with some
outlier measurements now obviously off more than their assigned
uncertainty (measurement bias/error), the shift seems OK and
will be less in the future.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
From Jon Giorgini, 2011 June 23:
Solution 1 uncertainties:
Uncertainties are high (12-hour output below); more
astrometry is needed to support pointing:
Date__(UT)__HR:MN POS_3sigma DOP_S_3sig DOP_X_3sig RT_delay_3sig
2011-Jun-25 00:00 246.989 1196.07 4277.97 0.092523
2011-Jun-25 12:00 633.243 1265.54 4526.45 0.114443
2011-Jun-26 00:00 1169.394 1423.79 5092.46 0.138354
2011-Jun-26 12:00 3331.609 1839.74 6580.18 0.165629
2011-Jun-27 00:00 10201.984 3595.82 12861.14 0.206386
2011-Jun-27 12:00 328858.072 85309.63 305126.21 0.246211
2011-Jun-28 00:00 15132.431 3511.71 12560.31 0.237290
2011-Jun-28 12:00 1625.939 428.59 1532.94 0.217070
2011-Jun-29 00:00 2639.231 303.15 1084.27 0.216485
We don't know the rotation period but there are preliminary indications that
the rotation period may be only minutes. The CW setup below is a standard
placeholder; we'll update it if the asteroid's rotation period becomes available
before the track.
The Doppler uncertainties are already small enough that a bandwidth of 4 kHz
will be fine.
CW setup:
---------------------------------------------------------------------------
TX polarization RCP
RCV polarization LCP (the HEMT at DSS-13 cannot receive both channels)
Frequency hops: 2
Dwell 30 seconds
Bandwidth: 4000 Hz
Sampling interval: 2500 x 0.1 usec
VME FFT for PSD files: 4096 for 0.98-Hz resolution
Ranging setups:
---------------------------------------------------------------------------
127 x 64 10-usec single sample
baud 10 usec
code 127
gates 127
PRP 1270 usec
FFT 64
CLT VME ?
PFS ?
ncoh 4
bandwidth 196.9 Hz
resolution 3.1 Hz
TXOFF +50 Hz -> echo will be centered at +16 bins or in bin 32 + 16 = 48
---------------------------------------------------------------------------
127 x 64 11-usec single sample
baud 11 usec
code 127
gates 127
PRP 1397 usec
FFT 64
CLT VME ?
PFS ?
ncoh 4
bandwidth 179.0 Hz
resolution 2.8 Hz
TXOFF +50 Hz --> echo will be centered at +18 bins or in bin 32 + 18 = 50
-------------------------------------------------------------------------
1-usec single sample
baud 1 usec
code 127
ncoh 20
bandwidth 393.7 Hz
FFT 128
dfreq 3.1 Hz
TXoff +50 Hz (echo in bin 64+16 =80)
-------------------------------------------------------------------------------
0.25-usec imaging
baud 0.25 usec
code 127
FFT 128
ncoh 246
bandwidth 128 Hz
resolution 1.00 Hz
TXOFF +20 Hz, echo is in bin 64+20=84
--------------------------------------------------------------------------
0.125-usec
------------
baud 0.125 usec
code 255
FFT 256
ncoh 122
bandwidth 257.15 Hz
resolution 1.0045 Hz
TXOFF +30 Hz to put echo at 128 + 30 = bin 158
_____________________________________________________________________
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
____________________________________________________________________
OSOD and predicts are on aardvark:
/export/data3/osod/ops/2011MD/PRDX.OUT.14v-13-13.bist.s2
/PUNCH.OUT.14v-13-13.bist.s2
/EPH.OUT.s2
POINTING
TX Offsets
Date (UTC) DOY hhmmss RA Dec Macro LHA Dec RTT OSOD
2011 06 26 177 050000 247.8546 35.1838 A 2.25 2
2011 06 26 060000 247.4059 35.0237 A 0.3 -0.1 2.20
2011 06 26 070000 246.9378 34.8179 AB 2.15
2011 06 26 080000 246.4713 34.5650 B 0.3 -0.1 2.11
2011 06 26 090000 246.0275 34.2664 BC 2.06
2011 06 26 100000 245.6258 33.9262 C 0.2 -0.2 2.01
2011 06 26 110000 245.2822 33.5509 C 1.97
Macro with Solution 6:
2011 06 26 177 060000 247.4049 35.0228 A 6
2011 06 26 070000 246.9367 34.8169 AB 0.3 -0.1
2011 06 26 080000 246.4701 34.5639 AB 0.3 -0.2
2011 06 26 090000 246.0262 34.2652 BC
2011 06 26 100000 245.6243 33.9249 C 0.2 -0.2
2011 06 26 110000 245.2805 33.5495 C
Transmit offsets are given in millidegrees.
Due to the decreasing round-trip light travel time, the SNR/RTT will increase
by about 60% during the track.
PRDX.OUT.s???
TRANSMITTER: STATION #14, RECEIVER: STATION #13
RECEIVER U.T. RANGE DOPPLER LHA DEC RA EL
...We will post this on June 26 after the orbit solution improves again...
2011 MD 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 300-233 | FAX: (818) 354-9476
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/2011MD/2011MD_planning.html
Asteroid Radar Astronomy