IOTA/IOTA-ES occultation update for (954) Li / HIP 42471 event on 2012 Oct 18, 23:28 UT Visible from SW Asia Summary ------- On 2012 Oct 18 UT, the 53 km diameter asteroid (954) Li will occult a 8.2 mag star in the constellation Cancer for observers along a path across SW Asia. In the case of an occultation, the combined light of the asteroid and the star will drop by 8.2 mag to 16.4 mag (the magnitude of the asteroid) for at most 2.7 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: . The event at a glimpse ---------------------- * Rank: 64 * date and approx. time of event: 2012 Oct 18, 23:23 - 2012 Oct 18, 23:27 UT * geocentric midpoint of event [JD]: 2456219.47825417 * magnitude of target star: 8.2 * magnitude drop [mag]: 8.2 * estimated maximum duration [s]: 2.7 * Moon: 17 % sunlit, 126° distance * Sun: 78° distance * rough path description: SW Asia The occultation path -------------------- * approximate projected width [km]: 55 * 1 sigma uncertainty interval [path widths]: +/- 0.94 * 1 sigma uncertainty interval [seconds]: +/- 3.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .026 +/- .019) * 1 sigma uncertainty ellipse (major, minor, PA): ( .026", .019", 95° ) * approx speed of asteroid's shadow [km/s]: 19.2304 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 42471 by 954 Li on 2012 Oct 18 Centre Star Star Sun Path Limits Error Limits E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4 o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " Latitude Latitude Latitude Latitude 12 0 0 27 41 50 23 23 19 0 70 -71 .. .. .. 27 57 34 .. .. .. 28 27 11 13 0 0 28 0 52 23 23 19 1 71 -71 27 45 10 28 16 34 27 15 44 28 46 9 14 0 0 28 19 35 23 23 20 2 71 -70 28 3 55 28 35 16 27 34 31 29 4 48 15 0 0 28 38 0 23 23 20 3 72 -69 28 22 22 28 53 40 27 53 1 29 23 9 16 0 0 28 56 7 23 23 20 4 72 -69 28 40 30 29 11 45 28 11 12 29 41 11 17 0 0 29 13 55 23 23 21 5 73 -68 28 58 19 29 29 31 28 29 4 29 58 55 18 0 0 29 31 24 23 23 21 6 73 -67 29 15 50 29 46 59 28 46 37 30 16 20 19 0 0 29 48 34 23 23 22 7 74 -67 29 33 1 30 4 7 29 3 51 30 33 25 20 0 0 30 5 24 23 23 22 7 74 -66 29 49 53 30 20 56 29 20 46 30 50 12 21 0 0 30 21 56 23 23 23 8 75 -65 30 6 26 30 37 26 29 37 22 31 6 39 22 0 0 30 38 7 23 23 24 9 75 -64 30 22 39 30 53 36 29 53 38 31 22 46 23 0 0 30 53 59 23 23 25 10 76 -64 30 38 33 31 9 27 30 9 34 31 38 34 24 0 0 31 9 32 23 23 26 11 76 -63 30 54 7 31 24 58 30 25 10 31 54 1 25 0 0 31 24 44 23 23 27 12 77 -62 31 9 20 31 40 8 30 40 27 32 9 9 26 0 0 31 39 36 23 23 28 13 77 -61 31 24 14 31 54 59 30 55 23 32 23 57 27 0 0 31 54 8 23 23 29 14 78 -60 31 38 47 32 9 29 31 9 59 32 38 25 28 0 0 32 8 19 23 23 31 15 78 -60 31 53 0 32 23 40 31 24 15 32 52 32 29 0 0 32 22 11 23 23 32 15 79 -59 32 6 53 32 37 29 31 38 11 33 6 19 30 0 0 32 35 42 23 23 33 16 79 -58 32 20 25 32 50 59 31 51 46 33 19 46 31 0 0 32 48 52 23 23 35 17 80 -57 32 33 37 33 4 8 32 5 0 33 32 52 32 0 0 33 1 42 23 23 36 18 81 -56 32 46 28 33 16 56 32 17 54 33 45 38 33 0 0 33 14 11 23 23 38 19 81 -56 32 58 59 33 29 24 32 30 27 33 58 3 34 0 0 33 26 19 23 23 40 20 82 -55 33 11 9 33 41 31 32 42 39 34 10 8 35 0 0 33 38 7 23 23 42 21 82 -54 33 22 58 33 53 18 32 54 31 34 21 52 36 0 0 33 49 34 23 23 43 22 83 -53 33 34 26 34 4 43 33 6 2 34 33 15 37 0 0 34 0 40 23 23 45 22 83 -52 33 45 34 34 15 48 33 17 12 34 44 17 38 0 0 34 11 26 23 23 47 23 84 -52 33 56 20 34 26 32 33 28 1 34 54 59 39 0 0 34 21 50 23 23 49 24 85 -51 34 6 46 34 36 55 33 38 29 35 5 20 40 0 0 34 31 54 23 23 52 25 85 -50 34 16 51 34 46 58 33 48 36 35 15 20 41 0 0 34 41 36 23 23 54 26 86 -49 34 26 35 34 56 39 33 58 22 35 24 59 42 0 0 34 50 58 23 23 56 27 87 -48 34 35 58 35 6 0 34 7 47 35 34 17 43 0 0 34 59 59 23 23 58 27 87 -48 34 44 59 35 14 59 34 16 51 35 43 15 44 0 0 35 8 39 23 24 1 28 88 -47 34 53 40 35 23 38 34 25 34 35 51 52 45 0 0 35 16 58 23 24 3 29 88 -46 35 2 0 35 31 56 34 33 56 36 0 8 46 0 0 35 24 56 23 24 5 30 89 -45 35 9 59 35 39 53 34 41 56 36 8 3 47 0 0 35 32 33 23 24 8 31 90 -44 35 17 37 35 47 29 34 49 36 36 15 37 48 0 0 35 39 49 23 24 10 32 90 -44 35 24 54 35 54 44 34 56 55 36 22 50 49 0 0 35 46 44 23 24 13 32 91 -43 35 31 50 36 1 38 35 3 53 36 29 42 50 0 0 35 53 18 23 24 16 33 92 -42 35 38 25 36 8 11 35 10 29 36 36 14 51 0 0 35 59 31 23 24 19 34 92 -41 35 44 39 36 14 24 35 16 45 36 42 25 52 0 0 36 5 23 23 24 21 35 93 -40 35 50 32 36 20 15 35 22 39 36 48 14 53 0 0 36 10 54 23 24 24 36 94 -40 35 56 4 36 25 45 35 28 12 36 53 43 54 0 0 36 16 4 23 24 27 36 94 -39 36 1 14 36 30 55 35 33 24 36 58 51 55 0 0 36 20 53 23 24 30 37 95 -38 36 6 4 36 35 43 35 38 15 37 3 39 56 0 0 36 25 22 23 24 33 38 96 -37 36 10 33 36 40 11 35 42 45 37 8 5 57 0 0 36 29 29 23 24 36 39 97 -36 36 14 41 36 44 17 35 46 54 37 12 11 58 0 0 36 33 15 23 24 39 40 97 -36 36 18 28 36 48 3 35 50 42 37 15 56 59 0 0 36 36 40 23 24 42 40 98 -35 36 21 54 36 51 28 35 54 9 37 19 20 60 0 0 36 39 45 23 24 45 41 99 -34 36 24 58 36 54 32 35 57 14 37 22 23 61 0 0 36 42 28 23 24 49 42 100 -33 36 27 42 36 57 15 35 59 59 37 25 5 62 0 0 36 44 51 23 24 52 43 100 -32 36 30 5 36 59 37 36 2 22 37 27 26 63 0 0 36 46 52 23 24 55 44 101 -32 36 32 7 37 1 38 36 4 25 37 29 27 64 0 0 36 48 33 23 24 59 44 102 -31 36 33 47 37 3 19 36 6 6 37 31 7 65 0 0 36 49 52 23 25 2 45 103 -30 36 35 7 37 4 38 36 7 26 37 32 26 66 0 0 36 50 51 23 25 5 46 104 -29 36 36 6 37 5 36 36 8 25 37 33 24 67 0 0 36 51 28 23 25 9 47 104 -28 36 36 44 37 6 14 36 9 3 37 34 1 68 0 0 36 51 45 23 25 13 48 105 -27 36 37 0 37 6 30 36 9 19 37 34 17 69 0 0 36 51 40 23 25 16 48 106 -27 36 36 56 37 6 26 36 9 15 37 34 13 70 0 0 36 51 15 23 25 20 49 107 -26 36 36 30 37 6 0 36 8 49 37 33 48 71 0 0 36 50 28 23 25 23 50 108 -25 36 35 44 37 5 14 36 8 3 37 33 1 72 0 0 36 49 21 23 25 27 51 109 -24 36 34 36 37 4 6 36 6 55 37 31 54 73 0 0 36 47 52 23 25 31 51 110 -23 36 33 7 37 2 38 36 5 25 37 30 26 74 0 0 36 46 2 23 25 35 52 111 -23 36 31 17 37 0 48 36 3 35 37 28 37 75 0 0 36 43 51 23 25 39 53 111 -22 36 29 6 36 58 38 36 1 23 37 26 27 76 0 0 36 41 19 23 25 43 54 112 -21 36 26 34 36 56 6 35 58 50 37 23 56 77 0 0 36 38 26 23 25 47 55 113 -20 36 23 40 36 53 13 35 55 56 37 21 4 78 0 0 36 35 12 23 25 51 55 114 -19 36 20 25 36 50 0 35 52 41 37 17 51 79 0 0 36 31 37 23 25 55 56 115 -19 36 16 49 36 46 25 35 49 4 37 14 17 80 0 0 36 27 40 23 25 59 57 117 -18 36 12 52 36 42 28 35 45 6 37 10 21 81 0 0 36 23 22 23 26 3 58 118 -17 36 8 34 36 38 11 35 40 46 37 6 5 82 0 0 36 18 43 23 26 7 58 119 -16 36 3 54 36 33 32 35 36 5 37 1 28 83 0 0 36 13 42 23 26 11 59 120 -15 35 58 53 36 28 33 35 31 3 36 56 29 84 0 0 36 8 20 23 26 15 60 121 -14 35 53 30 36 23 12 35 25 39 36 51 9 85 0 0 36 2 37 23 26 20 61 122 -14 35 47 46 36 17 29 35 19 54 36 45 28 86 0 0 35 56 33 23 26 24 61 124 -13 35 41 41 36 11 25 35 13 47 36 39 26 87 0 0 35 50 7 23 26 28 62 125 -12 35 35 14 36 5 0 35 7 19 36 33 3 88 0 0 35 43 19 23 26 33 63 126 -11 35 28 26 35 58 14 35 0 29 36 26 18 89 0 0 35 36 11 23 26 37 64 128 -10 35 21 16 35 51 6 34 53 17 36 19 12 90 0 0 35 28 40 23 26 42 64 129 -9 35 13 45 35 43 37 34 45 44 36 11 44 91 0 0 35 20 49 23 26 46 65 131 -9 35 5 52 35 35 46 34 37 50 36 3 55 92 0 0 35 12 35 23 26 51 66 132 -8 34 57 38 35 27 33 34 29 33 35 55 45 93 0 0 35 4 0 23 26 55 66 134 -7 34 49 2 35 19 0 34 20 55 35 47 13 94 0 0 34 55 4 23 27 0 67 135 -6 34 40 4 35 10 4 34 11 56 35 38 20 95 0 0 34 45 46 23 27 5 68 137 -5 34 30 45 35 0 47 34 2 34 35 29 5 96 0 0 34 36 6 23 27 10 69 139 -4 34 21 4 34 51 9 33 52 51 35 19 29 97 0 0 34 26 5 23 27 14 69 141 -4 34 11 2 34 41 9 33 42 47 35 9 31 98 0 0 34 15 42 23 27 19 70 143 -3 34 0 38 34 30 48 33 32 20 34 59 12 99 0 0 34 4 58 23 27 24 70 145 -2 33 49 52 34 20 4 33 21 32 34 48 31 100 0 0 33 53 52 23 27 29 71 148 -1 33 38 45 34 9 0 33 10 22 34 37 29 101 0 0 33 42 24 23 27 34 72 150 0 33 27 16 33 57 33 32 58 51 34 26 5 Uncertainty in time = +/- 4 secs Prediction of 2012 Jul 10.0 Data for the target star ------------------------ * name: HIP 42471 * constellation : Cancer * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 08 39 31.4913 DE: +17 28 41.177 * position source: mpos:HIP2 pm:HIP2 plx:HIP2 * standard error: RA,DE ["]: ( .021, .013 ) * V mag [mag]: 8.2 * B mag [mag]: 8.7 * Apparent position with proper motion RA(deg): 130.0648059033 DE(deg): 17.4307531612 * Equation of equinoxes (radians) : 0.000059770812996 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (954) Li approx. diameter [km]: 53 approx. diameter ["]: .020 distance from Earth [AU]: 3.68000 * orbital information: orbit source: Preston date of fit: 2012 Jul 10 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1564 number of rejected observations: 107 time covered by the observations: 1905 Oct 26 - 2012 Apr 01 1 sigma uncertainty ellipse (major, minor, PA): 0.016, 0.013, 103° remarks: * orbital elements for (954) Li : Mean anomaly = 148.28563607 deg Arg. of pericenter = 151.80767819 deg Long. of node = 163.25216973 deg Inclination = 1.16889587 deg Eccentricity = 0.17125379 Semimajor axis = 3.13115147 AU Perihelion dist = 2.59492992 AU Mag: H = 10.07, G = 0.15 Epoch of elements : MJD 56218.97800000 TDT (2012 Oct 18.978) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Oct 18 954 Li 23h 28.7m UT 8.2 8 39 31.491 17 28 41.18HIP 42471 8.7 16.4 53 2.7 3.680 1.747 -6.89 109.8586 17.480 -175.92 -10.04 23.4781 0.06097 0.22630 10.46384 -2.88454 -0.00566 0.00147 2000 146.68855320121010.00000151.807678163.252170 1.1688960.17125379 3.1311515 2.5949299 9.9 5.00.15 RATE 1.7788850 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.026 0.019 95 1.94 0.019 0 0 3-3 056118.0020121018__42471 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Aug 26, 04:36 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org