IOTA/IOTA-ES occultation update for (138) Tolosa / TYC 6836-00415-1 event on 2012 Sep 20, 13:04 UT Visible from SE Australia Summary ------- On 2012 Sep 20 UT, the 52 km diameter asteroid (138) Tolosa will occult a 11.3 mag star in the constellation Sagittarius for observers along a path across SE Australia. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.8 mag to 12.9 mag (the magnitude of the asteroid) for at most 2.6 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: 75 * date and approx. time of event: 2012 Sep 20, 13:04 - 2012 Sep 20, 13:08 UT * geocentric midpoint of event [JD]: 2456191.04446667 * magnitude of target star: 11.3 * magnitude drop [mag]: 1.8 * estimated maximum duration [s]: 2.6 * Moon: 24 % sunlit, 31° distance * Sun: 89° distance * rough path description: SE Australia The occultation path -------------------- * approximate projected width [km]: 57 * 1 sigma uncertainty interval [path widths]: +/- 0.75 * 1 sigma uncertainty interval [seconds]: +/- 1.8 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .030 +/- .029) * 1 sigma uncertainty ellipse (major, minor, PA): ( .030", .029", 91° ) * approx speed of asteroid's shadow [km/s]: 19.7176 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6836-00415-1 by 138 Tolosa on 2012 Sep 20 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 72 0 0 -50 26 31 13 4 4 66 358 0 -50 41 51 -50 11 12 -51 4 56 -49 48 17 73 0 0 -50 26 1 13 4 8 66 356 -1 -50 41 22 -50 10 42 -51 4 27 -49 47 47 74 0 0 -50 25 11 13 4 11 66 354 -2 -50 40 32 -50 9 52 -51 3 37 -49 46 56 75 0 0 -50 24 1 13 4 15 66 352 -2 -50 39 22 -50 8 42 -51 2 28 -49 45 46 76 0 0 -50 22 31 13 4 19 66 349 -3 -50 37 52 -50 7 11 -51 0 58 -49 44 14 77 0 0 -50 20 40 13 4 22 66 347 -4 -50 36 2 -50 5 20 -50 59 8 -49 42 23 78 0 0 -50 18 29 13 4 26 66 345 -4 -50 33 51 -50 3 8 -50 56 58 -49 40 10 79 0 0 -50 15 57 13 4 30 66 343 -5 -50 31 20 -50 0 36 -50 54 28 -49 37 37 80 0 0 -50 13 5 13 4 33 65 341 -6 -50 28 29 -49 57 44 -50 51 38 -49 34 44 81 0 0 -50 9 53 13 4 37 65 338 -6 -50 25 17 -49 54 30 -50 48 27 -49 31 30 82 0 0 -50 6 20 13 4 41 65 336 -7 -50 21 45 -49 50 57 -50 44 56 -49 27 55 83 0 0 -50 2 27 13 4 44 65 334 -8 -50 17 52 -49 47 2 -50 41 5 -49 23 59 84 0 0 -49 58 12 13 4 48 65 332 -8 -50 13 39 -49 42 47 -50 36 53 -49 19 43 85 0 0 -49 53 37 13 4 52 64 330 -9 -50 9 5 -49 38 11 -50 32 20 -49 15 6 86 0 0 -49 48 42 13 4 55 64 328 -10 -50 4 11 -49 33 15 -50 27 27 -49 10 7 87 0 0 -49 43 25 13 4 59 64 326 -10 -49 58 55 -49 27 57 -50 22 14 -49 4 48 88 0 0 -49 37 48 13 5 3 63 324 -11 -49 53 19 -49 22 18 -50 16 39 -48 59 8 89 0 0 -49 31 49 13 5 7 63 322 -12 -49 47 22 -49 16 19 -50 10 44 -48 53 6 90 0 0 -49 25 30 13 5 10 63 320 -12 -49 41 3 -49 9 58 -50 4 28 -48 46 43 91 0 0 -49 18 49 13 5 14 62 318 -13 -49 34 24 -49 3 16 -49 57 50 -48 39 59 92 0 0 -49 11 47 13 5 18 62 316 -14 -49 27 23 -48 56 12 -49 50 52 -48 32 54 93 0 0 -49 4 23 13 5 21 62 314 -14 -49 20 1 -48 48 47 -49 43 32 -48 25 26 94 0 0 -48 56 38 13 5 25 61 313 -15 -49 12 18 -48 41 1 -49 35 51 -48 17 37 95 0 0 -48 48 32 13 5 29 61 311 -16 -49 4 13 -48 32 52 -49 27 49 -48 9 27 96 0 0 -48 40 4 13 5 32 61 309 -16 -48 55 47 -48 24 23 -49 19 25 -48 0 54 97 0 0 -48 31 14 13 5 36 60 307 -17 -48 46 58 -48 15 31 -49 10 39 -47 52 0 98 0 0 -48 22 2 13 5 40 60 306 -18 -48 37 48 -48 6 17 -49 1 32 -47 42 43 99 0 0 -48 12 27 13 5 43 59 304 -18 -48 28 16 -47 56 41 -48 52 2 -47 33 5 100 0 0 -48 2 31 13 5 47 59 303 -19 -48 18 22 -47 46 43 -48 42 11 -47 23 4 101 0 0 -47 52 13 13 5 51 58 301 -20 -48 8 5 -47 36 22 -48 31 57 -47 12 40 102 0 0 -47 41 32 13 5 55 58 299 -20 -47 57 26 -47 25 40 -48 21 22 -47 1 55 103 0 0 -47 30 29 13 5 58 57 298 -21 -47 46 25 -47 14 34 -48 10 23 -46 50 46 104 0 0 -47 19 3 13 6 2 57 296 -22 -47 35 1 -47 3 6 -47 59 3 -46 39 15 105 0 0 -47 7 14 13 6 6 56 295 -23 -47 23 15 -46 51 15 -47 47 19 -46 27 21 106 0 0 -46 55 2 13 6 9 56 293 -23 -47 11 5 -46 39 1 -47 35 14 -46 15 4 107 0 0 -46 42 28 13 6 13 55 292 -24 -46 58 33 -46 26 25 -47 22 45 -46 2 24 108 0 0 -46 29 30 13 6 17 54 291 -25 -46 45 38 -46 13 25 -47 9 53 -45 49 20 109 0 0 -46 16 9 13 6 20 54 289 -25 -46 32 19 -46 0 2 -46 56 38 -45 35 54 110 0 0 -46 2 25 13 6 24 53 288 -26 -46 18 38 -45 46 15 -46 43 0 -45 22 4 111 0 0 -45 48 18 13 6 28 53 287 -27 -46 4 33 -45 32 5 -46 28 59 -45 7 50 112 0 0 -45 33 47 13 6 31 52 285 -28 -45 50 4 -45 17 32 -46 14 34 -44 53 13 113 0 0 -45 18 53 13 6 35 51 284 -28 -45 35 12 -45 2 35 -45 59 46 -44 38 13 114 0 0 -45 3 35 13 6 39 51 283 -29 -45 19 57 -44 47 15 -45 44 34 -44 22 49 115 0 0 -44 47 53 13 6 42 50 282 -30 -45 4 17 -44 31 30 -45 28 59 -44 7 1 116 0 0 -44 31 47 13 6 46 50 281 -31 -44 48 14 -44 15 22 -45 12 59 -43 50 49 117 0 0 -44 15 18 13 6 50 49 279 -31 -44 31 48 -43 58 50 -44 56 36 -43 34 13 118 0 0 -43 58 25 13 6 53 48 278 -32 -44 14 57 -43 41 55 -44 39 50 -43 17 14 119 0 0 -43 41 8 13 6 57 48 277 -33 -43 57 42 -43 24 35 -44 22 39 -42 59 50 120 0 0 -43 23 26 13 7 1 47 276 -34 -43 40 4 -43 6 51 -44 5 4 -42 42 2 121 0 0 -43 5 21 13 7 4 46 275 -34 -43 22 1 -42 48 43 -43 47 6 -42 23 51 122 0 0 -42 46 52 13 7 8 45 274 -35 -43 3 35 -42 30 12 -43 28 43 -42 5 15 123 0 0 -42 27 59 13 7 11 45 273 -36 -42 44 44 -42 11 16 -43 9 57 -41 46 16 124 0 0 -42 8 42 13 7 15 44 272 -37 -42 25 30 -41 51 57 -42 50 46 -41 26 53 125 0 0 -41 49 1 13 7 18 43 271 -38 -42 5 52 -41 32 13 -42 31 12 -41 7 5 126 0 0 -41 28 57 13 7 22 42 270 -38 -41 45 50 -41 12 6 -42 11 14 -40 46 54 127 0 0 -41 8 28 13 7 25 42 269 -39 -41 25 24 -40 51 35 -41 50 51 -40 26 19 128 0 0 -40 47 36 13 7 29 41 268 -40 -41 4 34 -40 30 40 -41 30 6 -40 5 21 129 0 0 -40 26 20 13 7 32 40 267 -41 -40 43 21 -40 9 22 -41 8 56 -39 43 59 130 0 0 -40 4 41 13 7 35 39 266 -42 -40 21 44 -39 47 40 -40 47 23 -39 22 14 131 0 0 -39 42 39 13 7 39 39 265 -42 -39 59 44 -39 25 36 -40 25 27 -39 0 5 132 0 0 -39 20 13 13 7 42 38 264 -43 -39 37 21 -39 3 8 -40 3 7 -38 37 34 133 0 0 -38 57 25 13 7 45 37 263 -44 -39 14 35 -38 40 17 -39 40 25 -38 14 40 134 0 0 -38 34 13 13 7 49 36 263 -45 -38 51 26 -38 17 3 -39 17 19 -37 51 23 135 0 0 -38 10 40 13 7 52 35 262 -46 -38 27 55 -37 53 27 -38 53 52 -37 27 43 136 0 0 -37 46 44 13 7 55 34 261 -46 -38 4 1 -37 29 29 -38 30 1 -37 3 42 137 0 0 -37 22 26 13 7 58 34 260 -47 -37 39 45 -37 5 9 -38 5 49 -36 39 19 138 0 0 -36 57 47 13 8 1 33 259 -48 -37 15 8 -36 40 28 -37 41 15 -36 14 34 139 0 0 -36 32 46 13 8 4 32 259 -49 -36 50 9 -36 15 25 -37 16 19 -35 49 29 140 0 0 -36 7 24 13 8 7 31 258 -50 -36 24 50 -35 50 2 -36 51 3 -35 24 2 141 0 0 -35 41 42 13 8 10 30 257 -50 -35 59 10 -35 24 18 -36 25 25 -34 58 16 142 0 0 -35 15 40 13 8 13 29 256 -51 -35 33 9 -34 58 14 -35 59 28 -34 32 9 143 0 0 -34 49 19 13 8 16 28 256 -52 -35 6 49 -34 31 50 -35 33 10 -34 5 43 144 0 0 -34 22 38 13 8 18 27 255 -53 -34 40 10 -34 5 8 -35 6 34 -33 38 58 145 0 0 -33 55 38 13 8 21 26 254 -54 -34 13 12 -33 38 7 -34 39 38 -33 11 55 146 0 0 -33 28 20 13 8 23 25 254 -54 -33 45 56 -33 10 48 -34 12 24 -32 44 33 147 0 0 -33 0 45 13 8 26 24 253 -55 -33 18 22 -32 43 11 -33 44 52 -32 16 55 148 0 0 -32 32 53 13 8 28 24 252 -56 -32 50 31 -32 15 18 -33 17 3 -31 48 59 149 0 0 -32 4 44 13 8 31 23 252 -57 -32 22 24 -31 47 8 -32 48 58 -31 20 48 150 0 0 -31 36 20 13 8 33 22 251 -58 -31 54 0 -31 18 42 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24 35 164 0 0 -24 38 0 13 8 55 7 244 -66 -24 55 45 -24 20 19 -25 22 27 -23 53 51 165 0 0 -24 7 12 13 8 56 6 244 -66 -24 24 56 -23 49 31 -24 51 37 -23 23 4 166 0 0 -23 36 21 13 8 57 5 243 -67 -23 54 4 -23 18 40 -24 20 44 -22 52 15 167 0 0 -23 5 28 13 8 57 4 243 -67 -23 23 10 -22 47 48 -23 49 49 -22 21 23 168 0 0 -22 34 34 13 8 58 3 242 -67 -22 52 15 -22 16 55 -23 18 53 -21 50 32 169 0 0 -22 3 40 13 8 58 2 242 -67 -22 21 20 -21 46 2 -22 47 57 -21 19 40 170 0 0 -21 32 47 13 8 58 1 242 -68 -21 50 27 -21 15 10 -22 17 1 -20 48 50 171 0 0 -21 1 56 13 8 58 0 241 -68 -21 19 35 .. .. .. -21 46 7 .. .. .. Uncertainty in time = +/- 2 secs Prediction of 2012 Sep 8.0 Data for the target star ------------------------ * name: TYC 6836-00415-1 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 17 47 44.2060 DE: -26 36 57.786 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .027, .028 ) * V mag [mag]: 11.3 * B mag [mag]: 11.6 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (138) Tolosa approx. diameter [km]: 52 approx. diameter ["]: .039 distance from Earth [AU]: 1.81600 * orbital information: orbit source: Preston date of fit: 2012 Sep 07 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 1348 number of rejected observations: 113 time covered by the observations: 1905 Nov 30 - 2012 Aug 21 1 sigma uncertainty ellipse (major, minor, PA): 0.013, 0.009, 95° remarks: * orbital elements for (138) Tolosa : Mean anomaly = 346.85920645 deg Arg. of pericenter = 259.85088199 deg Long. of node = 54.90750094 deg Inclination = 3.20682344 deg Eccentricity = 0.16175753 Semimajor axis = 2.44890660 AU Perihelion dist = 2.05277752 AU Mag: H = 8.69, G = 0.15 Epoch of elements : MJD 56190.54500000 TDT (2012 Sep 20.545) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 20 138 Tolosa 13h 4.0m UT 11.3 17 47 44.206-26 36 57.79TYC 6836-00415-1 11.7 12.9 52 2.6 1.816 4.018 0.12 71.1004 -26.617 -17.69 0.80 13.0672 0.00088 -0.40013 11.12914 0.02340 0.00531 -0.00012 2000 346.7190402012 920.00000259.850882 54.907501 3.2068230.16175753 2.4489066 2.0527775 8.8 5.00.15 RATE 2.5718510 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.030 0.029 91 1.75 0.030 0 0 0 4 056178.0020120920_0415-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Sep 07, 23:02 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org