IOTA/IOTA-ES occultation update for (895) Helio / 2UCAC 36098811 event on 2012 Dec 13, 04:20 UT Visible from Canada, USA, Mexico Summary ------- On 2012 Dec 13 UT, the 128 km diameter asteroid (895) Helio will occult a 13.1 mag star in the constellation Canis Minor for observers along a path across Canada, USA, Mexico. In the case of an occultation, the combined light of the asteroid and the star will drop by 0.5 mag to 12.5 mag (the magnitude of the asteroid) for at most 9.1 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC. The event at a glimpse ---------------------- * Rank: 97 * date and approx. time of event: 2012 Dec 13, 04:16 - 2012 Dec 13, 04:25 UT * geocentric midpoint of event [JD]: 2456274.68110417 * magnitude of target star: 13.1 * magnitude drop [mag]: 0.5 * estimated maximum duration [s]: 9.1 * Moon: 0 % sunlit, 149° distance * Sun: 151° distance * rough path description: Canada, USA, Mexico The occultation path -------------------- * approximate projected width [km]: 216 * 1 sigma uncertainty interval [path widths]: +/- 0.39 * 1 sigma uncertainty interval [seconds]: +/- 3.3 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .041 +/- .030) * 1 sigma uncertainty ellipse (major, minor, PA): ( .042", .030", 103° ) * approx speed of asteroid's shadow [km/s]: 14.0926 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 36098811 by 895 Helio on 2012 Dec 13 Centre Star Star Sun Path Limit1 Path Limit2 Error Limit1 Error Limit2 E. Longitude Latitude U.T. Alt Az Alt o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' " Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude 162 40 41 83 16 54 4 16 26 6 20 -19 178 17 3 86 37 11 ... .. .. .. .. .. -150 20 48 88 8 40 ... .. .. .. .. .. -167 19 18 86 4 29 4 16 33 9 50 -22 -127 33 7 87 19 36 171 42 35 83 7 25 - 93 16 21 87 5 21 ... .. .. .. .. .. -125 42 27 86 17 7 4 16 40 12 91 -25 - 94 28 34 85 58 42 -158 8 50 85 17 18 - 78 8 11 85 13 53 -176 30 4 83 24 57 -100 34 12 85 3 0 4 16 46 14 116 -27 - 82 33 27 84 14 44 -125 44 57 85 14 40 - 72 55 21 83 25 53 -147 6 3 84 40 22 - 89 2 22 83 27 57 4 16 53 16 127 -29 - 77 22 28 82 32 55 -105 23 41 84 6 42 - 70 39 9 81 44 58 -121 39 31 84 15 1 - 83 13 48 81 52 5 4 17 0 18 133 -31 - 74 45 44 80 56 30 - 94 32 12 82 39 24 - 69 35 36 80 10 31 -105 51 53 83 5 18 - 79 59 26 80 19 42 4 17 7 19 136 -32 - 73 21 26 79 25 25 - 88 27 19 81 9 15 - 69 8 12 78 41 31 - 96 42 30 81 41 48 - 78 4 18 78 51 30 4 17 14 20 138 -34 - 72 36 13 77 59 3 - 84 48 13 79 40 58 - 69 1 3 77 17 8 - 91 10 45 80 15 49 - 76 54 24 77 27 18 4 17 21 22 139 -35 - 72 14 13 76 36 47 - 82 29 57 78 15 47 - 69 6 12 75 56 40 - 87 39 57 78 51 9 - 76 12 31 76 6 43 4 17 28 23 139 -37 - 72 7 0 75 18 4 - 81 0 15 76 53 54 - 69 19 18 74 39 36 - 85 20 46 77 28 57 - 75 49 1 74 49 21 4 17 35 24 139 -38 - 72 9 41 74 2 27 - 80 1 40 75 35 7 - 69 37 44 73 25 28 - 83 46 44 76 9 32 - 75 38 11 73 34 50 4 17 42 25 139 -39 - 72 19 16 72 49 34 - 79 24 7 74 19 12 - 69 59 54 72 13 55 - 82 42 43 74 52 49 - 75 36 22 72 22 51 4 17 48 26 139 -40 - 72 33 51 71 39 5 - 79 1 20 73 5 53 - 70 24 46 71 4 40 - 81 59 32 73 38 38 - 75 41 14 71 13 9 4 17 55 27 138 -42 - 72 52 8 70 30 46 - 78 49 19 71 54 54 - 70 51 35 69 57 28 - 81 31 21 72 26 48 - 75 51 8 70 5 29 4 18 2 27 138 -43 - 73 13 12 69 24 23 - 78 45 21 70 46 2 - 71 19 52 68 52 6 - 81 14 17 71 17 6 - 76 4 54 68 59 40 4 18 9 28 137 -44 - 73 36 26 68 19 45 - 78 47 34 69 39 5 - 71 49 17 67 48 24 - 81 5 42 70 9 20 - 76 21 44 67 55 31 4 18 16 29 136 -45 - 74 1 23 67 16 42 - 78 54 36 68 33 53 - 72 19 34 66 46 13 - 81 3 41 69 3 21 - 76 41 1 66 52 53 4 18 23 29 136 -46 - 74 27 41 66 15 5 - 79 5 30 67 30 15 - 72 50 33 65 45 25 - 81 6 53 67 59 0 - 77 2 18 65 51 38 4 18 30 30 135 -47 - 74 55 6 65 14 47 - 79 19 30 66 28 4 - 73 22 4 64 45 52 - 81 14 17 66 56 8 - 77 25 14 64 51 39 4 18 37 31 134 -48 - 75 23 25 64 15 42 - 79 36 4 65 27 13 - 73 54 3 63 47 29 - 81 25 7 65 54 37 - 77 49 32 63 52 51 4 18 44 31 133 -49 - 75 52 31 63 17 44 - 79 54 46 64 27 36 - 74 26 25 62 50 11 - 81 38 48 64 54 22 - 78 15 0 62 55 7 4 18 50 32 132 -49 - 76 22 16 62 20 48 - 80 15 16 63 29 6 - 74 59 5 61 53 51 - 81 54 53 63 55 17 - 78 41 28 61 58 24 4 18 57 32 131 -50 - 76 52 35 61 24 49 - 80 37 19 62 31 38 - 75 32 3 60 58 27 - 82 13 0 62 57 15 - 79 8 49 61 2 35 4 19 4 33 130 -51 - 77 23 24 60 29 43 - 81 0 41 61 35 8 - 76 5 15 60 3 54 - 82 32 52 62 0 14 - 79 36 56 60 7 39 4 19 11 33 130 -52 - 77 54 39 59 35 27 - 81 25 13 60 39 32 - 76 38 41 59 10 9 - 82 54 15 61 4 7 - 80 5 44 59 13 30 4 19 18 34 129 -53 - 78 26 18 58 41 56 - 81 50 47 59 44 45 - 77 12 20 58 17 8 - 83 16 59 60 8 51 - 80 35 10 58 20 6 4 19 25 34 128 -53 - 78 58 20 57 49 8 - 82 17 16 58 50 45 - 77 46 11 57 24 48 - 83 40 54 59 14 24 - 81 5 10 57 27 24 4 19 32 34 127 -54 - 79 30 43 56 57 0 - 82 44 36 57 57 28 - 78 20 13 56 33 7 - 84 5 54 58 20 40 - 81 35 41 56 35 20 4 19 39 35 126 -55 - 80 3 25 56 5 29 - 83 12 40 57 4 52 - 78 54 28 55 42 2 - 84 31 52 57 27 38 - 82 6 43 55 43 53 4 19 45 35 125 -55 - 80 36 27 55 14 34 - 83 41 27 56 12 53 - 79 28 54 54 51 31 - 84 58 43 56 35 15 - 82 38 13 54 52 59 4 19 52 35 124 -56 - 81 9 47 54 24 11 - 84 10 54 55 21 30 - 80 3 33 54 1 31 - 85 26 23 55 43 28 - 83 10 10 54 2 38 4 19 59 35 123 -57 - 81 43 26 53 34 18 - 84 40 58 54 30 39 - 80 38 24 53 12 1 - 85 54 50 54 52 15 - 83 42 33 53 12 46 4 20 6 36 122 -57 - 82 17 23 52 44 54 - 85 11 37 53 40 19 - 81 13 28 52 22 59 - 86 24 0 54 1 33 - 84 15 22 52 23 22 4 20 13 36 121 -58 - 82 51 39 51 55 57 - 85 42 50 52 50 28 - 81 48 46 51 34 23 - 86 53 51 53 11 21 - 84 48 37 51 34 24 4 20 20 36 120 -58 - 83 26 14 51 7 25 - 86 14 37 52 1 3 - 82 24 18 50 46 12 - 87 24 22 52 21 36 - 85 22 18 50 45 50 4 20 27 36 119 -59 - 84 1 8 50 19 17 - 86 46 56 51 12 4 - 83 0 4 49 58 23 - 87 55 32 51 32 16 - 85 56 24 49 57 39 4 20 34 36 117 -59 - 84 36 22 49 31 30 - 87 19 47 50 23 28 - 83 36 7 49 10 55 - 88 27 20 50 43 21 - 86 30 55 49 9 48 4 20 41 36 116 -60 - 85 11 56 48 44 4 - 87 53 10 49 35 14 - 84 12 27 48 23 47 - 88 59 45 49 54 48 - 87 5 53 48 22 18 4 20 47 36 115 -60 - 85 47 52 47 56 56 - 88 27 5 48 47 19 - 84 49 4 47 36 58 - 89 32 47 49 6 35 - 87 41 19 47 35 5 4 20 54 36 114 -60 - 86 24 10 47 10 7 - 89 1 32 47 59 44 - 85 26 0 46 50 26 - 90 6 25 48 18 42 - 88 17 11 46 48 10 4 21 1 36 113 -61 - 87 0 51 46 23 33 - 89 36 32 47 12 26 - 86 3 17 46 4 9 - 90 40 41 47 31 6 - 88 53 33 46 1 30 4 21 8 36 112 -61 - 87 37 57 45 37 15 - 90 12 6 46 25 24 - 86 40 54 45 18 8 - 91 15 34 46 43 47 - 89 30 23 45 15 4 4 21 15 36 111 -61 - 88 15 28 44 51 10 - 90 48 13 45 38 37 - 87 18 54 44 32 20 - 91 51 5 45 56 42 - 90 7 45 44 28 51 4 21 22 36 110 -61 - 88 53 25 44 5 19 - 91 24 56 44 52 2 - 87 57 18 43 46 44 - 92 27 15 45 9 51 - 90 45 38 43 42 50 4 21 29 36 109 -61 - 89 31 51 43 19 38 - 92 2 14 44 5 40 - 88 36 7 43 1 19 - 93 4 5 44 23 13 - 91 24 5 42 57 0 4 21 36 35 108 -62 - 90 10 46 42 34 8 - 92 40 11 43 19 29 - 89 15 23 42 16 5 - 93 41 36 43 36 45 - 92 3 8 42 11 19 4 21 42 35 107 -62 - 90 50 13 41 48 47 - 93 18 47 42 33 27 - 89 55 8 41 31 0 - 94 19 50 42 50 27 - 92 42 47 41 25 46 4 21 49 35 106 -62 - 91 30 13 41 3 35 - 93 58 3 41 47 34 - 90 35 24 40 46 2 - 94 58 49 42 4 17 - 93 23 4 40 40 20 4 21 56 35 105 -62 - 92 10 49 40 18 29 - 94 38 3 41 1 48 - 91 16 12 40 1 11 - 95 38 33 41 18 14 - 94 4 3 39 55 0 4 22 3 34 104 -62 - 92 52 1 39 33 29 - 95 18 48 40 16 7 - 91 57 35 39 16 27 - 96 19 7 40 32 17 - 94 45 46 39 9 45 4 22 10 34 103 -61 - 93 33 53 38 48 33 - 96 0 20 39 30 31 - 92 39 35 38 31 46 - 97 0 32 39 46 25 - 95 28 14 38 24 33 4 22 17 34 102 -61 - 94 16 28 38 3 41 - 96 42 43 38 44 59 - 93 22 14 37 47 10 - 97 42 51 39 0 35 - 96 11 32 37 39 23 4 22 24 33 101 -61 - 94 59 48 37 18 52 - 97 25 59 37 59 28 - 94 5 36 37 2 35 - 98 26 7 38 14 48 - 96 55 41 36 54 14 4 22 31 33 100 -61 - 95 43 55 36 34 3 - 98 10 12 37 13 58 - 94 49 43 36 18 2 - 99 10 23 37 29 0 - 97 40 47 36 9 4 4 22 38 32 99 -61 - 96 28 55 35 49 14 - 98 55 26 36 28 26 - 95 34 38 35 33 29 - 99 55 45 36 43 11 - 98 26 53 35 23 53 4 22 44 32 98 -60 - 97 14 49 35 4 24 - 99 41 45 35 42 53 - 96 20 25 34 48 54 -100 42 16 35 57 20 - 99 14 2 34 38 38 4 22 51 31 97 -60 - 98 1 43 34 19 30 -100 29 14 34 57 15 - 97 7 9 34 4 17 -101 30 2 35 11 23 -100 2 22 33 53 17 4 22 58 31 96 -59 - 98 49 41 33 34 32 -101 17 58 34 11 31 - 97 54 53 33 19 35 -102 19 9 34 25 20 -100 51 56 33 7 50 4 23 5 30 95 -59 - 99 38 49 32 49 28 -102 8 3 33 25 40 - 98 43 42 32 34 48 -103 9 43 33 39 9 -101 42 52 32 22 15 4 23 12 30 94 -58 -100 29 11 32 4 16 -102 59 38 32 39 39 - 99 33 42 31 49 53 -104 1 53 32 52 46 -102 35 16 31 36 28 4 23 19 29 93 -58 -101 20 56 31 18 54 -103 52 50 31 53 25 -100 24 59 31 4 50 -104 55 47 32 6 10 -103 29 18 30 50 28 4 23 26 28 93 -57 -102 14 10 30 33 21 -104 47 48 31 6 57 -101 17 40 30 19 35 -105 51 36 31 19 18 -104 25 8 30 4 12 4 23 33 28 92 -56 -103 9 2 29 47 33 -105 44 45 30 20 11 -102 11 53 29 34 8 -106 49 33 30 32 7 -105 22 56 29 17 38 4 23 39 27 91 -55 -104 5 42 29 1 28 -106 43 52 29 33 4 -103 7 47 28 48 24 -107 49 53 29 44 32 -106 22 56 28 30 41 4 23 46 26 90 -55 -105 4 23 28 15 3 -107 45 27 28 45 32 -104 5 33 28 2 22 -108 52 54 28 56 29 -107 25 26 27 43 19 4 23 53 25 89 -54 -106 5 17 27 28 15 -108 49 48 27 57 30 -105 5 23 27 15 59 -109 58 59 28 7 53 -108 30 44 26 55 25 4 24 0 24 88 -53 -107 8 43 26 41 0 -109 57 20 27 8 53 -106 7 33 26 29 10 -111 8 35 27 18 38 -109 39 15 26 6 54 4 24 7 23 87 -52 -108 15 0 25 53 12 -111 8 33 26 19 34 -107 12 21 25 41 52 -112 22 18 26 28 35 -110 51 30 25 17 40 4 24 14 22 87 -51 -109 24 35 25 4 45 -112 24 5 25 29 23 -108 20 9 24 53 59 -113 40 57 25 37 32 -112 8 10 24 27 32 4 24 21 21 86 -49 -110 37 58 24 15 33 -113 44 48 24 38 9 -109 31 24 24 5 25 -115 5 36 24 45 16 -113 30 7 23 36 19 4 24 28 20 85 -48 -111 55 53 23 25 26 -115 11 54 23 45 36 -110 46 42 23 16 1 -116 37 48 23 51 26 -114 58 35 22 43 45 4 24 35 18 84 -46 -113 19 13 22 34 11 -116 47 4 22 51 21 -112 6 48 22 25 38 -118 19 50 22 55 32 -116 35 22 21 49 25 4 24 41 17 83 -45 -114 49 17 21 41 31 -118 32 58 21 54 50 -113 32 44 21 34 1 -120 15 36 21 56 42 -118 23 12 20 52 44 4 24 48 15 83 -43 -116 27 57 20 47 1 -120 34 3 20 55 3 -115 5 57 20 40 51 -122 32 17 20 53 22 -120 26 50 19 52 38 4 24 55 13 82 -41 -118 18 10 19 50 2 -122 59 13 19 50 5 -116 48 38 19 45 40 -125 27 20 19 41 45 -122 55 48 18 47 4 4 25 2 10 81 -38 -120 25 2 18 49 28 -126 12 4 18 34 49 -118 44 17 18 47 40 -130 26 51 18 3 20 -126 16 29 17 30 20 4 25 9 7 80 -35 -122 59 6 17 43 0 ... .. .. .. .. .. -120 59 16 17 45 30 ... .. .. .. .. .. Uncertainty in time = +/- 4 secs Prediction of 2012 Dec 3.0 Data for the target star ------------------------ * name: 2UCAC 36098811 * constellation : Canis Minor * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 07 13 39.8283 DE: +12 02 30.580 * position source: mpos:UCAC4 pm:UCAC4 * standard error: RA,DE ["]: ( .033, .027 ) * V mag [mag]: 13.1 * B mag [mag]: 0.0 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (895) Helio approx. diameter [km]: 128 approx. diameter ["]: .096 distance from Earth [AU]: 1.84300 * orbital information: orbit source: Preston date of fit: 2012 Nov 29 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 1034 number of rejected observations: 56 time covered by the observations: 1906 Jun 21 - 2012 Nov 28 1 sigma uncertainty ellipse (major, minor, PA): 0.027, 0.014, 121° remarks: * orbital elements for (895) Helio : Mean anomaly = 12.95113571 deg Arg. of pericenter = 178.19154918 deg Long. of node = 264.70458265 deg Inclination = 26.08546963 deg Eccentricity = 0.14706729 Semimajor axis = 3.20265130 AU Perihelion dist = 2.73164604 AU Mag: H = 8.31, G = 0.15 Epoch of elements : MJD 56274.18100000 TDT (2012 Dec 13.181) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Dec 13 895 Helio 4h 20.8m UT 13.1 7 13 39.828 12 2 30.582UCAC 36098811 0.0 12.5 128 9.1 1.843 -2.040 -23.35 -39.0432 12.049 113.37 -23.17 4.3465 -0.49649 0.63528 -6.26942 -4.89537 -0.00256 0.00128 2000 12.232151201212 9.00000178.191549264.704583 26.0854700.14706729 3.2026513 2.7316461 8.3 5.00.15 RATE 1.7196480 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.042 0.030 103 1.39 0.037 0 0 3 0 056264.0020121213_098811 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Nov 29, 23:15 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org