2014 BR57 Goldstone Radar Observations Planning
Sequence of images with a resolution of 3.75 meters x 0.06 Hz. Time delay (range) increases down and Doppler frequency increases to the right, so the rotation is counterclockwise. Each image is a weighted sum of 15 individual transmit-receive cycles. The images were obtained during an interval of 4.2 hours on February 18 when the asteroid was 0.018 AU (7 lunar dsitances) from Earth. The images indicate that 2014 BR57 is a rounded object and suggest that it's roughly 80 meters in diameter. Radar-bright spots appear in two locations and persist over a range of rotation phases. The spots appear in frames 5, 6, 7 at the trailing edge of the echo and in frames 11, 12, and 13 near the two o'clock position. The spots are more conspicuous in the movie (a link is provided below). The images suggest that the rotation period is a few hours. Radar astrometry obtained on Feb. 18 permits reliable orbit estimation for 261 years and has prevented this object from being lost. The encounter in 2014 was the closest for the forseeable future. Although there have been problems recently with one of the klystrons, we were fortunate with these observations that both klystrons were operational and that we were able to transmit 440 kW.
An animation showing 2014 BR57 rotating is available here.
2014 BR57 was discovered by the Mt. Lemmon Survey (Arizona) on January 28, 2014. It has an absolute magnitude of 23.9 suggesting a diameter within a factor of two of 60 meters, but nothing else is known about its physical properties. 2014 BR57 will approach within 0.011 AU (4.3 lunar distances) on February 20. We have time scheduled on Feb. 18 to observe this asteroid. Due to the klystron problem, we will be running at 200 kW. The SNRs probably won't be strong but we are cautiously optimistic that we'll still get a detection. Arecibo is offline due to damage experienced during an earthquake on January 13, so Goldstone provides our only chance to observe this asteroid with radar.
Orbital and Physical Characteristics orbit type Apollo semimajor axis 1.357 AU eccentricity 0.398 inclination 3.8 deg perihelion distance 0.817 AU aphelion distance 1.896 AU absolute magnitude (H) 23.9 diameter 60 m (+/- a factor of two) rotation period unknown pole direction unknown lightcurve amplitude unknown spectral class unknown Last update: 2014 February 19
M.P.E.C. 2014-B80 Issued 2014 Jan. 30, 20:13 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 2014 BR57 Observations: K14B57R* C2014 01 28.37791 09 51 28.06 +28 38 58.4 20.3 VqEB080G96 K14B57R C2014 01 28.38733 09 51 28.15 +28 39 06.4 21.1 VqEB080G96 K14B57R C2014 01 28.39200 09 51 28.21 +28 39 10.2 21.0 VqEB080G96 K14B57R C2014 01 28.45897 09 51 28.75 +28 40 04.8 20.9 VqEB080G96 K14B57R C2014 01 28.46349 09 51 28.74 +28 40 08.6 20.5 VqEB080G96 K14B57R C2014 01 28.46804 09 51 28.83 +28 40 12.0 20.9 VqEB080G96 K14B57R C2014 01 28.47257 09 51 28.86 +28 40 15.2 19.5 VqEB080G96 K14B57R KC2014 01 30.26509 09 52 25.09 +29 08 03.7 20.3 RoEB080291 K14B57R KC2014 01 30.26950 09 52 25.10 +29 08 08.4 20.7 RoEB080291 K14B57R KC2014 01 30.27390 09 52 25.14 +29 08 13.2 20.5 RoEB080291 K14B57R C2014 01 30.44949 09 52 25.88 +29 11 08.5 20.7 RoEB080926 K14B57R C2014 01 30.46503 09 52 25.99 +29 11 22.8 21.1 RoEB080926 K14B57R C2014 01 30.47934 09 52 26.11 +29 11 35.6 21.0 RoEB080926 Observer details: 291 LPL/Spacewatch II. Observer R. A. Mastaler. 1.8-m f/2.7 reflector + CCD. 926 Tenagra II Observatory. Observers M. Schwartz, P. R. Holvorcem. 0.41-m f/3.75 astrograph + CCD, 0.81-m f/7 Ritchey-Chretien + CCD. G96 Mt. Lemmon Survey. Observer A. R. Gibbs. Measurers E. J. Christensen, A. R. Gibbs, A. D. Grauer, R. E. Hill, J. A. Johnson, R. A. Kowalski, S. M. Larson, F. C. Shelly. 1.5-m reflector + CCD. Orbital elements: 2014 BR57 Earth MOID = 0.0115 AU Epoch 2013 Nov. 4.0 TT = JDT 2456600.5 MPC M 262.25657 (2000.0) P Q n 0.62268309 Peri. 236.99938 -0.78259773 +0.62217413 a 1.3581821 Node 341.44810 -0.54690236 -0.70323540 e 0.3989325 Incl. 3.78081 -0.29738629 -0.34403390 P 1.58 H 23.8 G 0.15 U 9 Residuals in seconds of arc 140128 G96 0.7- 0.2+ 140128 G96 0.4+ 0.0 140130 926 0.0 0.1- 140128 G96 0.3- 0.2+ 140128 G96 0.1+ 0.4- 140130 926 0.1- 0.1+ 140128 G96 0.2+ 0.0 140130 291 0.2+ 0.0 140130 926 0.2- 0.0 140128 G96 0.5+ 0.1- 140130 291 0.1- 0.0 140128 G96 0.2- 0.1+ 140130 291 0.0 0.0 Ephemeris: 2014 BR57 a,e,i = 1.36, 0.40, 4 q = 0.8164 Date TT R. A. (2000) Decl. Delta r Elong. Phase V 2013 12 31 09 31 10.2 +25 15 22 0.3912 1.3112 141.1 28.1 23.6 ... 2014 01 15 09 43 49.9 +26 25 04 0.2574 1.2179 152.6 21.8 22.3 ... 2014 01 23 09 48 44.2 +27 32 55 0.1942 1.1668 158.2 18.3 21.5 ... 2014 01 29 09 51 46.4 +28 48 13 0.1502 1.1283 161.3 16.2 20.8 2014 01 30 09 52 15.1 +29 03 51 0.1431 1.1219 161.7 16.0 20.7 2014 01 31 09 52 43.9 +29 20 38 0.1361 1.1154 162.0 15.9 20.6 ... 2014 02 06 09 56 01.8 +31 37 35 0.09539 1.0771 161.9 16.6 19.7 ... 2014 02 14 10 07 47.3 +39 38 50 0.04408 1.0270 153.2 25.7 18.3 ... 2014 03 01 21 36 28.1 -14 09 17 0.05424 0.9395 18.3 160.6 28.5 A. U. Tomatic (C) Copyright 2014 MPC M.P.E.C. 2014-B80
2014 BR57 D = 60 meters P = 0.5 h (an educated guess) OC albedo = 0.1 (a relatively conservative lower bound) w DOY start date window RA, dec dist runs SNR/day SNR/run 8 48 2014 Feb 17 01:45-15:40 159, +52 0.024 1040 27 1 8 49 2014 Feb 18 01:31-17:23 166, +61 0.018 1488 81 2 Scheduled 8 50 2014 Feb 19-20 01:03-02:10 198, +74 0.014 2870 300 6 Visible continuously for more than 24 hours 8 51 2014 Feb 20-21 07:07-00:44 297, +59 0.011 2391 590 13 8 52 2014 Feb 21-22 12:21-00:07 312, +31 0.013 1580 270 7 8 53 2014 Feb 22 13:39-23:40 317, +13 0.017 1032 84 3 8 54 2014 Feb 23 14:19-23:19 320, +3 0.023 715 27 1 Goldstone SNRs assume Ptx = 200 kW Arecibo SNRs ...Arecibo is still offline...
Goldstone tracks: 049 0005 0135 0715 0745 DSS-14 GSSR AST 2014 BR57 UT UT PST Duration Round-trip SNR/ DOY Date TX Window TX Window hh:mm time (sec) Run --- ---- --------- --------- --------- --------- ---- 049 Feb 18 0100-0715 1700-2315 Feb 17 6:15 18 2 Assumes Ptx = 200 kW Arecibo tracks: ...none...
From Jon Giorgini, 2014 Feb 17: New optical measurements have been reported for 2014 BR57. Based on 51 observations (Jan 28-Feb 15),2014 BR57 orbit solution #14 was estimated. OSOD and nominal predicts have been updated on aardvark. Formal 3-sigma X-band uncertainties for 2014 BR57: Date__(UT)__HR:MN POS_3sigma DOP_X_3sig RT_delay_3sig 2014-Feb-18 00:00 6.051 1531.87 0.061122 2014-Feb-18 01:00 6.415 1524.84 0.060487 2014-Feb-18 02:00 6.787 1517.57 0.059854 2014-Feb-18 03:00 7.160 1510.05 0.059224 2014-Feb-18 04:00 7.526 1502.27 0.058597 2014-Feb-18 05:00 7.881 1494.22 0.057974 2014-Feb-18 06:00 8.218 1485.90 0.057354 2014-Feb-18 07:00 8.537 1477.31 0.056738 2014-Feb-18 08:00 8.834 1468.42 0.056125 - - - - - - - - - - - - - - - - - - - - From Jon Giorgini, 2014 Feb 14: Based on 44 optical maeasurements (Jan 28-Feb 13), 2014 BR57 orbit solution #10 was estimated. OSOD with nominal predicts was established on aardvark. Formal 3-sigma X-band uncertainties for (s10): Date__(UT)__HR:MN POS_3sigma DOP_X_3sig RT_delay_3sig 2014-Feb-18 01:00 35.795 3168.41 0.130534 2014-Feb-18 02:00 37.442 3154.96 0.129219 2014-Feb-18 03:00 39.097 3140.93 0.127910 2014-Feb-18 04:00 40.737 3126.30 0.126607 2014-Feb-18 05:00 42.342 3111.08 0.125310 2014-Feb-18 06:00 43.896 3095.29 0.124019 2014-Feb-18 07:00 45.391 3078.92 0.122735 2014-Feb-18 08:00 46.824 3062.03 0.121458 Will be updated Monday or sooner if more data is reported. =================================================================== 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-Feb-14 00:00 152.16497 39.56855 0.04400640969560 18.37 153.2282 /L 31.5/ 98.9 2014-Feb-15 00:00 153.18388 41.93981 0.03787696842908 18.11 150.5483 /L 33.9/ 99.8 2014-Feb-16 00:00 154.71754 45.17646 0.03185847581595 17.83 146.9474 /L 40.6/ 98.9 2014-Feb-17 00:00 157.28526 49.82407 0.02601348472379 17.52 141.8375 /L 50.3/ 96.2 2014-Feb-18 00:00 162.43341 56.89253 0.02047696717722 17.21 134.0443 /L 62.2/ 91.6 2014-Feb-19 00:00 177.30093 67.89939 0.01556859965321 16.97 121.1443 /L 76.0/ 85.3 2014-Feb-20 00:00 249.74862 75.57929 0.01207101138938 17.11 99.0743 /L 90.4/ 77.4 2014-Feb-21 00:00 302.52413 51.91563 0.01136838652227 18.40 68.2891 /L 97.3/ 68.2 2014-Feb-22 00:00 313.63855 26.48887 0.01389459615210 21. 42.3395 /L 89.9/ 57.9 2014-Feb-23 00:00 317.95137 10.79814 0.01836791190535 24. 27.5290 /L 76.2/ 47.0 2014-Feb-24 00:00 320.22733 1.64619 0.02371847341311 26. 20.2123 /L 61.4/ 35.9 2014-Feb-25 00:00 321.63823 -4.04906 0.02948124444768 28. 17.0985 /L 46.5/ 25.3
We don't know anything about the spin state, but if it's similar to other tiny asteroids, it could have a rapid rotation period in the realm of only ten minutes. If so, then the bandwidth could be roughly 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
OSOD and predicts are aardvark: Monostatic with the new waveform generator: /export/data3/osod/ops/2014br57/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...
2014 BR57 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/2014BR57/2014BR57_planning.html