IOTA/IOTA-ES occultation update for (895) Helio / 2UCAC 40005164 event on 2012 Sep 29, 17:17 UT Visible from Japan, China Summary ------- On 2012 Sep 29 UT, the 128 km diameter asteroid (895) Helio will occult a 12.0 mag star in the constellation Gemini for observers along a path across Japan, China. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.9 mag to 13.7 mag (the magnitude of the asteroid) for at most 6.0 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: UCAC. The event at a glimpse ---------------------- * Rank: 93 * date and approx. time of event: 2012 Sep 29, 17:16 - 2012 Sep 29, 17:20 UT * geocentric midpoint of event [JD]: 2456200.22302083 * magnitude of target star: 12.0 * magnitude drop [mag]: 1.9 * estimated maximum duration [s]: 6.0 * Moon: 100 % sunlit, 102° distance * Sun: 82° distance * rough path description: Japan, China Additional comments ------------------- 12" double star The occultation path -------------------- * approximate projected width [km]: 129 * 1 sigma uncertainty interval [path widths]: +/- 0.48 * 1 sigma uncertainty interval [seconds]: +/- 2.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .027 +/- .032) * 1 sigma uncertainty ellipse (major, minor, PA): ( .032", .027", 3° ) * approx speed of asteroid's shadow [km/s]: 21.2808 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 40005164 by 895 Helio on 2012 Sep 29 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 99 0 0 20 25 20 17 16 12 0 65 -72 .. .. .. 21 3 47 .. .. .. 21 40 39 100 0 0 20 51 22 17 16 12 1 65 -72 20 13 0 21 29 40 19 36 7 22 6 24 101 0 0 21 16 46 17 16 12 2 66 -71 20 38 33 21 54 56 20 1 48 22 31 32 102 0 0 21 41 32 17 16 12 3 66 -71 21 3 27 22 19 34 20 26 51 22 56 2 103 0 0 22 5 41 17 16 12 4 66 -70 21 27 45 22 43 34 20 51 16 23 19 54 104 0 0 22 29 12 17 16 13 5 67 -70 21 51 24 23 6 57 21 15 3 23 43 9 105 0 0 22 52 6 17 16 13 6 67 -69 22 14 25 23 29 43 21 38 13 24 5 47 106 0 0 23 14 21 17 16 14 7 68 -68 22 36 49 23 51 50 22 0 44 24 27 47 107 0 0 23 36 0 17 16 15 8 68 -68 22 58 36 24 13 21 22 22 38 24 49 10 108 0 0 23 57 1 17 16 16 9 68 -67 23 19 44 24 34 14 22 43 54 25 9 56 109 0 0 24 17 24 17 16 16 10 69 -66 23 40 15 24 54 30 23 4 33 25 30 5 110 0 0 24 37 11 17 16 17 11 69 -66 24 0 9 25 14 10 23 24 34 25 49 37 111 0 0 24 56 20 17 16 18 12 70 -65 24 19 26 25 33 12 23 43 57 26 8 32 112 0 0 25 14 53 17 16 19 13 70 -64 24 38 6 25 51 37 24 2 44 26 26 51 113 0 0 25 32 49 17 16 21 14 70 -63 24 56 8 26 9 26 24 20 53 26 44 34 114 0 0 25 50 8 17 16 22 15 71 -63 25 13 34 26 26 39 24 38 25 27 1 40 115 0 0 26 6 51 17 16 23 16 71 -62 25 30 23 26 43 15 24 55 20 27 18 10 116 0 0 26 22 57 17 16 25 17 72 -61 25 46 36 26 59 15 25 11 39 27 34 4 117 0 0 26 38 27 17 16 26 18 72 -60 26 2 12 27 14 39 25 27 21 27 49 22 118 0 0 26 53 21 17 16 28 19 73 -59 26 17 12 27 29 27 25 42 27 28 4 5 119 0 0 27 7 40 17 16 29 20 73 -59 26 31 36 27 43 40 25 56 57 28 18 12 120 0 0 27 21 22 17 16 31 20 74 -58 26 45 24 27 57 17 26 10 50 28 31 44 121 0 0 27 34 29 17 16 33 21 74 -57 26 58 37 28 10 19 26 24 7 28 44 41 122 0 0 27 47 1 17 16 34 22 74 -56 27 11 13 28 22 46 26 36 49 28 57 2 123 0 0 27 58 57 17 16 36 23 75 -56 27 23 15 28 34 37 26 48 55 29 8 49 124 0 0 28 10 19 17 16 38 24 75 -55 27 34 41 28 45 54 27 0 26 29 20 2 125 0 0 28 21 5 17 16 40 25 76 -54 27 45 32 28 56 36 27 11 21 29 30 40 126 0 0 28 31 17 17 16 42 26 76 -53 27 55 48 29 6 44 27 21 41 29 40 43 127 0 0 28 40 54 17 16 44 27 77 -52 28 5 28 29 16 17 27 31 25 29 50 12 128 0 0 28 49 56 17 16 46 28 77 -52 28 14 35 29 25 15 27 40 35 29 59 7 129 0 0 28 58 24 17 16 49 29 78 -51 28 23 6 29 33 40 27 49 10 30 7 28 130 0 0 29 6 18 17 16 51 29 78 -50 28 31 3 29 41 30 27 57 10 30 15 16 131 0 0 29 13 38 17 16 53 30 79 -49 28 38 26 29 48 47 28 4 36 30 22 29 132 0 0 29 20 23 17 16 56 31 79 -48 28 45 14 29 55 29 28 11 27 30 29 9 133 0 0 29 26 35 17 16 58 32 79 -48 28 51 28 30 1 38 28 17 43 30 35 16 134 0 0 29 32 12 17 17 1 33 80 -47 28 57 8 30 7 13 28 23 26 30 40 48 135 0 0 29 37 16 17 17 3 34 80 -46 29 2 14 30 12 15 28 28 33 30 45 48 136 0 0 29 41 46 17 17 6 35 81 -45 29 6 46 30 16 43 28 33 7 30 50 14 137 0 0 29 45 42 17 17 9 36 81 -44 29 10 44 30 20 38 28 37 7 30 54 7 138 0 0 29 49 4 17 17 11 37 82 -44 29 14 8 30 23 59 28 40 32 30 57 27 139 0 0 29 51 53 17 17 14 37 82 -43 29 16 58 30 26 46 28 43 23 31 0 14 140 0 0 29 54 9 17 17 17 38 83 -42 29 19 14 30 29 1 28 45 40 31 2 27 141 0 0 29 55 50 17 17 20 39 83 -41 29 20 56 30 30 42 28 47 23 31 4 7 142 0 0 29 56 58 17 17 23 40 83 -40 29 22 5 30 31 49 28 48 32 31 5 15 143 0 0 29 57 33 17 17 26 41 84 -40 29 22 40 30 32 24 28 49 7 31 5 49 144 0 0 29 57 34 17 17 29 42 84 -39 29 22 41 30 32 25 28 49 8 31 5 50 145 0 0 29 57 1 17 17 32 43 85 -38 29 22 8 30 31 52 28 48 35 31 5 18 146 0 0 29 55 55 17 17 35 44 85 -37 29 21 1 30 30 47 28 47 28 31 4 12 147 0 0 29 54 15 17 17 38 44 85 -36 29 19 20 30 29 7 28 45 46 31 2 34 148 0 0 29 52 1 17 17 42 45 86 -36 29 17 5 30 26 55 28 43 31 31 0 22 149 0 0 29 49 14 17 17 45 46 86 -35 29 14 17 30 24 9 28 40 41 30 57 37 150 0 0 29 45 53 17 17 48 47 87 -34 29 10 54 30 20 49 28 37 16 30 54 19 151 0 0 29 41 57 17 17 52 48 87 -33 29 6 57 30 16 55 28 33 18 30 50 27 152 0 0 29 37 28 17 17 55 49 87 -32 29 2 25 30 12 28 28 28 44 30 46 1 153 0 0 29 32 24 17 17 59 50 88 -32 28 57 20 30 7 26 28 23 36 30 41 2 154 0 0 29 26 46 17 18 2 51 88 -31 28 51 39 30 1 51 28 17 54 30 35 29 155 0 0 29 20 34 17 18 6 51 88 -30 28 45 24 29 55 41 28 11 36 30 29 22 156 0 0 29 13 47 17 18 10 52 89 -29 28 38 35 29 48 58 28 4 43 30 22 41 157 0 0 29 6 26 17 18 14 53 89 -28 28 31 10 29 41 39 27 57 16 30 15 26 158 0 0 28 58 30 17 18 17 54 89 -27 28 23 10 29 33 47 27 49 13 30 7 36 159 0 0 28 49 59 17 18 21 55 90 -27 28 14 35 29 25 19 27 40 34 29 59 12 160 0 0 28 40 52 17 18 25 56 90 -26 28 5 25 29 16 17 27 31 20 29 50 14 161 0 0 28 31 11 17 18 29 57 90 -25 27 55 39 29 6 39 27 21 30 29 40 40 162 0 0 28 20 53 17 18 33 58 90 -24 27 45 18 28 56 26 27 11 4 29 30 31 163 0 0 28 10 0 17 18 37 59 91 -23 27 34 20 28 45 38 27 0 2 29 19 47 164 0 0 27 58 32 17 18 41 59 91 -22 27 22 46 28 34 14 26 48 24 29 8 28 165 0 0 27 46 27 17 18 46 60 91 -21 27 10 36 28 22 14 26 36 9 28 56 33 166 0 0 27 33 45 17 18 50 61 91 -21 26 57 50 28 9 38 26 23 17 28 44 2 167 0 0 27 20 28 17 18 54 62 91 -20 26 44 26 27 56 26 26 9 48 28 30 56 168 0 0 27 6 33 17 18 59 63 91 -19 26 30 26 27 42 37 25 55 42 28 17 12 169 0 0 26 52 2 17 19 3 64 91 -18 26 15 48 27 28 12 25 40 59 28 2 53 170 0 0 26 36 53 17 19 7 65 91 -17 26 0 33 27 13 9 25 25 38 27 47 56 171 0 0 26 21 7 17 19 12 66 91 -16 25 44 41 26 57 30 25 9 39 27 32 23 172 0 0 26 4 43 17 19 17 67 91 -15 25 28 10 26 41 13 24 53 2 27 16 12 173 0 0 25 47 41 17 19 21 68 91 -14 25 11 2 26 24 18 24 35 47 26 59 24 174 0 0 25 30 2 17 19 26 69 90 -14 24 53 15 26 6 45 24 17 53 26 41 58 175 0 0 25 11 43 17 19 31 69 90 -13 24 34 49 25 48 34 23 59 20 26 23 54 176 0 0 24 52 47 17 19 36 70 90 -12 24 15 45 25 29 45 23 40 9 26 5 12 177 0 0 24 33 11 17 19 40 71 89 -11 23 56 2 25 10 18 23 20 18 25 45 52 178 0 0 24 12 57 17 19 45 72 88 -10 23 35 39 24 50 11 22 59 48 25 25 53 179 0 0 23 52 3 17 19 50 73 88 -9 23 14 37 24 29 26 22 38 38 25 5 15 180 0 0 23 30 30 17 19 55 74 87 -8 22 52 56 24 8 1 22 16 49 24 43 59 -179 0 0 23 8 17 17 20 1 75 85 -7 22 30 35 23 45 57 21 54 19 24 22 3 -178 0 0 22 45 25 17 20 6 76 84 -6 22 7 34 23 23 13 21 31 10 23 59 27 -177 0 0 22 21 53 17 20 11 77 82 -5 21 43 53 22 59 50 21 7 20 23 36 12 -176 0 0 21 57 40 17 20 16 78 80 -4 21 19 31 22 35 46 20 42 50 23 12 17 -175 0 0 21 32 48 17 20 22 79 78 -3 20 54 30 22 11 3 20 17 40 22 47 43 -174 0 0 21 7 15 17 20 27 79 75 -2 20 28 47 21 45 39 19 51 48 22 22 28 -173 0 0 20 41 2 17 20 32 80 72 -1 20 2 25 21 19 36 19 25 17 21 56 33 -172 0 0 20 14 8 17 20 38 81 67 0 19 35 22 20 52 52 18 58 4 21 29 59 Uncertainty in time = +/- 3 secs Prediction of 2012 Jul 3.0 Data for the target star ------------------------ * name: 2UCAC 40005164 * constellation : Gemini * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 07 03 33.3484 DE: +23 21 45.311 * position source: mpos:UCAC4 pm:UCAC4 * standard error: RA,DE ["]: ( .018, .031 ) * V mag [mag]: 12.0 * B mag [mag]: 0.0 * Apparent position with proper motion RA(deg): 106.0851570382 DE(deg): 23.3415078204 * Equation of equinoxes (radians) : 0.000063991125268 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (895) Helio approx. diameter [km]: 128 approx. diameter ["]: .066 distance from Earth [AU]: 2.68100 * orbital information: orbit source: Preston date of fit: 2012 Jul 03 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1076 number of rejected observations: 57 time covered by the observations: 1906 Jun 21 - 2012 Feb 22 1 sigma uncertainty ellipse (major, minor, PA): 0.021, 0.010, 124° remarks: * orbital elements for (895) Helio : Mean anomaly = 0.09931955 deg Arg. of pericenter = 178.25514945 deg Long. of node = 264.70380903 deg Inclination = 26.08233353 deg Eccentricity = 0.14737338 Semimajor axis = 3.20385806 AU Perihelion dist = 2.73169468 AU Mag: H = 8.31, G = 0.15 Epoch of elements : MJD 56199.72000000 TDT (2012 Sep 29.720) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 29 895 Helio 17h 21.2m UT 12.0 7 3 33.348 23 21 45.312UCAC 40005164 0.0 13.7 128 6.0 2.681 2.505 -19.04 -163.2714 23.368 -82.76 -2.77 17.3525 -0.05705 -0.10173 10.51644 -5.80351 -0.00559 0.00062 2000 358.4287662012 920.00000178.255149264.703809 26.0823340.14737338 3.2038581 2.7316947 8.3 5.00.15 RATE 1.7186770 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.032 0.027 3 1.48 0.032 0 0 4 1 056111.0020120929_005164 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Aug 05, 23:05 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org