IOTA/IOTA-ES occultation update for (94) Aurora / UCAC2 18780862 event on 2012 Sep 13, 15:06 UT Visible from China, SE Asia Summary ------- On 2012 Sep 13 UT, the 218 km diameter asteroid (94) Aurora will occult a 11.3 mag star in the constellation Sagittarius for observers along a path across China, SE Asia. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.2 mag to 13.3 mag (the magnitude of the asteroid) for at most 34.6 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC. The event at a glimpse ---------------------- * Rank: 86 * date and approx. time of event: 2012 Sep 13, 14:58 - 2012 Sep 13, 15:23 UT * geocentric midpoint of event [JD]: 2456184.12931667 * magnitude of target star: 11.3 * magnitude drop [mag]: 2.2 * estimated maximum duration [s]: 34.6 * Moon: 7 % sunlit, 141° distance * Sun: 111° distance * rough path description: China, SE Asia The occultation path -------------------- * approximate projected width [km]: 218 * 1 sigma uncertainty interval [path widths]: +/- 0.58 * 1 sigma uncertainty interval [seconds]: +/- 18.6 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .062 +/- .062) * 1 sigma uncertainty ellipse (major, minor, PA): ( .062", .062", 90° ) * approx speed of asteroid's shadow [km/s]: 6.2962 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC2 18780862 by 94 Aurora on 2012 Sep 13 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 ' " Longitude Longitude Longitude Longitude 120 6 0 39 0 0 15 23 4 1 227 -47 ... .. .. 118 16 0 ... .. .. 116 11 25 118 44 57 38 0 0 15 23 3 2 226 -48 120 34 6 116 58 14 122 44 7 114 57 10 117 27 32 37 0 0 15 23 2 4 226 -48 119 13 27 115 43 48 121 19 22 113 45 57 116 13 24 36 0 0 15 23 0 5 225 -49 117 56 22 114 32 24 119 58 35 112 37 30 115 2 16 35 0 0 15 22 57 7 224 -50 116 42 33 113 23 47 118 41 23 111 31 36 113 53 53 34 0 0 15 22 54 8 224 -50 115 31 42 112 17 43 117 27 27 110 28 2 112 48 2 33 0 0 15 22 50 9 223 -51 114 23 34 111 14 0 116 16 30 109 26 39 111 44 31 32 0 0 15 22 46 11 222 -51 113 17 57 110 12 28 115 8 16 108 27 16 110 43 9 31 0 0 15 22 42 12 222 -52 112 14 39 109 12 56 114 2 33 107 29 44 109 43 46 30 0 0 15 22 37 13 221 -52 111 13 28 108 15 16 112 59 9 106 33 56 108 46 15 29 0 0 15 22 31 15 221 -53 110 14 17 107 19 20 111 57 53 105 39 45 107 50 27 28 0 0 15 22 25 16 220 -53 109 16 55 106 25 0 110 58 37 104 47 3 106 56 15 27 0 0 15 22 18 17 220 -53 108 21 16 105 32 11 110 1 11 103 55 45 106 3 33 26 0 0 15 22 11 19 220 -54 107 27 12 104 40 46 109 5 27 103 5 45 105 12 14 25 0 0 15 22 4 20 219 -54 106 34 37 103 50 39 108 11 20 102 16 58 104 22 12 24 0 0 15 21 56 21 219 -54 105 43 25 103 1 45 107 18 41 101 29 19 103 33 24 23 0 0 15 21 48 22 219 -54 104 53 31 102 14 0 106 27 26 100 42 44 102 45 44 22 0 0 15 21 39 24 218 -54 104 4 49 101 27 19 105 37 28 99 57 8 101 59 8 21 0 0 15 21 30 25 218 -54 103 17 15 100 41 38 104 48 43 99 12 28 101 13 31 20 0 0 15 21 21 26 218 -54 102 30 44 99 56 53 104 1 7 98 28 40 100 28 50 19 0 0 15 21 11 27 217 -54 101 45 12 99 13 0 103 14 33 97 45 41 99 45 1 18 0 0 15 21 1 29 217 -54 101 0 36 98 29 57 102 29 0 97 3 27 99 2 1 17 0 0 15 20 50 30 217 -54 100 16 52 97 47 38 101 44 22 96 21 55 98 19 46 16 0 0 15 20 39 31 217 -54 99 33 57 97 6 3 101 0 37 95 41 3 97 38 14 15 0 0 15 20 28 32 217 -54 98 51 47 96 25 7 100 17 40 95 0 47 96 57 22 14 0 0 15 20 16 34 216 -54 98 10 19 95 44 49 99 35 30 94 21 6 96 17 7 13 0 0 15 20 4 35 216 -54 97 29 31 95 5 5 98 54 1 93 41 56 95 37 26 12 0 0 15 19 51 36 216 -53 96 49 20 94 25 53 98 13 13 93 3 16 94 58 17 11 0 0 15 19 39 37 216 -53 96 9 43 93 47 10 97 33 2 92 25 2 94 19 37 10 0 0 15 19 26 38 216 -53 95 30 38 93 8 54 96 53 25 91 47 13 93 41 24 9 0 0 15 19 12 40 216 -53 94 52 2 92 31 4 96 14 21 91 9 46 93 3 37 8 0 0 15 18 58 41 216 -52 94 13 53 91 53 36 95 35 46 90 32 40 92 26 12 7 0 0 15 18 44 42 216 -52 93 36 9 91 16 29 94 57 39 89 55 52 91 49 7 6 0 0 15 18 30 43 216 -51 92 58 48 90 39 40 94 19 56 89 19 20 91 12 22 5 0 0 15 18 15 44 216 -51 92 21 47 90 3 8 93 42 37 88 43 3 90 35 53 4 0 0 15 18 0 46 216 -50 91 45 5 89 26 51 93 5 39 88 6 58 89 59 38 3 0 0 15 17 45 47 216 -50 91 8 40 88 50 47 92 28 59 87 31 4 89 23 37 2 0 0 15 17 30 48 216 -49 90 32 30 88 14 53 91 52 37 86 55 19 88 47 46 1 0 0 15 17 14 49 216 -49 89 56 32 87 39 9 91 16 29 86 19 40 88 12 5 0 0 0 15 16 58 50 216 -48 89 20 45 87 3 31 90 40 35 85 44 6 87 36 30 - 1 0 0 15 16 41 52 216 -48 88 45 7 86 27 59 90 4 52 85 8 36 Latitude Latitude Latitude Latitude 86 0 0 - 3 43 22 15 15 55 55 216 -46 - 5 39 51 - 1 47 20 - 7 55 39 0 26 50 85 0 0 - 5 25 2 15 15 26 57 216 -45 - 7 21 35 - 3 28 53 - 9 37 26 - 1 14 32 84 0 0 - 7 6 28 15 14 55 59 216 -44 - 9 2 57 - 5 10 21 -11 18 40 - 2 55 59 83 0 0 - 8 47 25 15 14 25 61 217 -43 -10 43 41 - 6 51 28 -12 59 6 - 4 37 14 82 0 0 -10 27 37 15 13 53 63 217 -41 -12 23 32 - 8 31 59 -14 38 29 - 6 18 4 81 0 0 -12 6 50 15 13 22 65 218 -40 -14 2 16 -10 11 39 -16 16 34 - 7 58 12 80 0 0 -13 44 51 15 12 50 67 218 -39 -15 39 39 -11 50 15 -17 53 10 - 9 37 26 79 0 0 -15 21 26 15 12 18 69 219 -38 -17 15 29 -13 27 32 -19 28 4 -11 15 30 78 0 0 -16 56 24 15 11 47 71 219 -36 -18 49 34 -15 3 20 -21 1 5 -12 52 12 77 0 0 -18 29 34 15 11 15 72 220 -35 -20 21 45 -16 37 26 -22 32 5 -14 27 21 76 0 0 -20 0 47 15 10 44 74 221 -34 -21 51 54 -18 9 41 -24 0 56 -16 0 46 75 0 0 -21 29 54 15 10 13 76 222 -32 -23 19 52 -19 39 56 -25 27 32 -17 32 17 74 0 0 -22 56 51 15 9 42 78 224 -31 -24 45 35 -21 8 5 -26 51 47 -19 1 46 73 0 0 -24 21 30 15 9 12 80 225 -30 -26 8 58 -22 34 0 -28 13 38 -20 29 8 72 0 0 -25 43 49 15 8 42 81 228 -29 -27 29 57 -23 57 38 -29 33 2 -21 54 15 71 0 0 -27 3 45 15 8 13 83 231 -27 -28 48 30 -25 18 54 -30 49 59 -23 17 5 70 0 0 -28 21 15 15 7 44 84 235 -26 -30 4 36 -26 37 48 -32 4 27 -24 37 34 69 0 0 -29 36 20 15 7 16 85 242 -25 -31 18 16 -27 54 17 -33 16 27 -25 55 40 68 0 0 -30 48 59 15 6 49 86 257 -24 -32 29 29 -29 8 21 -34 26 0 -27 11 22 67 0 0 -31 59 13 15 6 22 87 291 -23 -33 38 18 -30 20 0 -35 33 8 -28 24 40 66 0 0 -33 7 4 15 5 57 87 340 -22 -34 44 43 -31 29 17 -36 37 54 -29 35 35 65 0 0 -34 12 34 15 5 31 86 6 -20 -35 48 48 -32 36 11 -37 40 20 -30 44 7 64 0 0 -35 15 45 15 5 7 85 18 -19 -36 50 35 -33 40 46 -38 40 30 -31 50 20 63 0 0 -36 16 41 15 4 43 84 24 -18 -37 50 8 -34 43 5 -39 38 26 -32 54 15 62 0 0 -37 15 24 15 4 20 83 29 -17 -38 47 30 -35 43 10 -40 34 13 -33 55 55 61 0 0 -38 11 58 15 3 58 82 31 -16 -39 42 44 -36 41 4 -41 27 55 -34 55 23 60 0 0 -39 6 27 15 3 36 80 34 -15 -40 35 54 -37 36 52 -42 19 34 -35 52 42 59 0 0 -39 58 54 15 3 15 79 36 -14 -41 27 5 -38 30 35 -43 9 16 -36 47 55 58 0 0 -40 49 23 15 2 54 78 37 -13 -42 16 19 -39 22 20 -43 57 4 -37 41 7 57 0 0 -41 37 58 15 2 34 77 39 -13 -43 3 41 -40 12 8 -44 43 2 -38 32 21 56 0 0 -42 24 43 15 2 15 76 40 -12 -43 49 15 -41 0 4 -45 27 14 -39 21 39 55 0 0 -43 9 41 15 1 56 75 41 -11 -44 33 4 -41 46 11 -46 9 43 -40 9 7 54 0 0 -43 52 56 15 1 38 74 42 -10 -45 15 12 -42 30 33 -46 50 34 -40 54 48 53 0 0 -44 34 31 15 1 21 73 43 -9 -45 55 43 -43 13 14 -47 29 50 -41 38 45 52 0 0 -45 14 31 15 1 4 72 44 -8 -46 34 40 -43 54 17 -48 7 34 -42 21 2 51 0 0 -45 52 58 15 0 47 71 45 -8 -47 12 6 -44 33 45 -48 43 50 -43 1 42 50 0 0 -46 29 57 15 0 31 70 46 -7 -47 48 5 -45 11 43 -49 18 42 -43 40 49 49 0 0 -47 5 29 15 0 16 69 47 -6 -48 22 41 -45 48 12 -49 52 11 -44 18 25 48 0 0 -47 39 38 15 0 0 68 48 -5 -48 55 55 -46 23 17 -50 24 22 -44 54 35 47 0 0 -48 12 28 14 59 46 67 49 -5 -49 27 52 -46 57 1 -50 55 17 -45 29 21 46 0 0 -48 44 1 14 59 31 66 50 -4 -49 58 33 -47 29 25 -51 24 59 -46 2 45 45 0 0 -49 14 19 14 59 18 65 51 -3 -50 28 2 -48 0 33 -51 53 31 -46 34 52 44 0 0 -49 43 26 14 59 4 65 52 -3 -50 56 21 -48 30 28 -52 20 55 -47 5 43 43 0 0 -50 11 24 14 58 51 64 53 -2 -51 23 33 -48 59 12 -52 47 14 -47 35 22 42 0 0 -50 38 15 14 58 38 63 54 -1 -51 49 40 -49 26 48 -53 12 29 -48 3 50 41 0 0 -51 4 2 14 58 26 62 55 -1 -52 14 44 -49 53 18 -53 36 44 -48 31 10 Uncertainty in time = +/- 20 secs Prediction of 2012 Sep 8.0 Data for the target star ------------------------ * name: UCAC2 18780862 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 58 12.9309 DE: -31 13 51.442 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .062, .062 ) * V mag [mag]: 11.3 * B mag [mag]: 0.0 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (94) Aurora approx. diameter [km]: 218 approx. diameter ["]: .107 distance from Earth [AU]: 2.79700 * orbital information: orbit source: Preston date of fit: 2012 Sep 07 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1115 number of rejected observations: 97 time covered by the observations: 1901 Oct 14 - 2012 Sep 01 1 sigma uncertainty ellipse (major, minor, PA): 0.010, 0.008, 83° remarks: * orbital elements for (94) Aurora : Mean anomaly = 244.85375997 deg Arg. of pericenter = 60.22400060 deg Long. of node = 2.66803687 deg Inclination = 7.96456439 deg Eccentricity = 0.08920382 Semimajor axis = 3.15907730 AU Perihelion dist = 2.87727554 AU Mag: H = 7.53, G = 0.15 Epoch of elements : MJD 56183.62900000 TDT (2012 Sep 13.629) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 13 94 Aurora 15h 6.2m UT 11.3 18 58 12.931-31 13 51.44UCAC2 18780862 0.0 13.3 218 34.6 2.797 0.565 8.51 64.9895 -31.233 -47.62 3.48 15.1036 0.02116 -0.01788 2.30200 2.70736 0.00534 0.00086 2000 244.2167442012 910.00000 60.224001 2.668037 7.9645640.08920382 3.1590773 2.8772755 7.6 5.00.15 RATE 1.7553490 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.062 0.062 90 1.58 0.062 0 0-1-2 056178.0020120913_780862 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Sep 07, 22:48 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org