IOTA/IOTA-ES occultation update for (1242) Zambesia / TYC 0260-00499-1 event on 2008 May 18, 03:40 UT Visible from Chile, Argentina Summary ------- On 2008 May 18 UT, the 48 km diameter asteroid (1242) Zambesia will occult a 10.0 mag star in the constellation Sextans for observers along a path across Chile, Argentina. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.6 mag to 15.6 mag (the magnitude of the asteroid) for at most 5.5 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: 58 * date and approx. time of event: 2008 May 18, 03:39 - 2008 May 18, 03:52 UT * magnitude of target star: 10.0 * magnitude drop [mag]: 5.6 * estimated maximum duration [s]: 5.5 * Moon: 96 % sunlit, 55° distance * Sun: 103° distance * rough path description: Chile, Argentina The occultation path -------------------- * approximate projected width [km]: 50 * 1 sigma uncertainty interval [path widths]: +/- 1.08 * 1 sigma uncertainty interval [seconds]: +/- 8.1 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .037 +/- .026) * 1 sigma uncertainty ellipse (major, minor, PA): ( .038", .025", 103° ) * approx speed of asteroid's shadow [km/s]: 8.7310 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 0260-00499-1 by 1242 Zambesia on 2008 May 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 ' " Longitude Longitude Longitude Longitude - 55 36 35 -52 0 0 3 52 31 3 284 -58 - 57 13 41 - 53 51 35 - 60 23 21 ... .. .. - 61 50 2 -51 0 0 3 52 26 7 288 -59 - 63 5 12 - 60 31 27 - 65 37 48 - 57 27 7 Latitude Latitude Latitude Latitude - 63 0 0 -50 46 49 3 52 25 8 289 -59 -51 1 0 -50 32 40 -51 31 41 -50 2 8 - 64 0 0 -50 35 1 3 52 24 9 290 -59 -50 49 14 -50 20 49 -51 20 1 -49 50 12 - 65 0 0 -50 22 44 3 52 22 9 291 -59 -50 37 0 -50 8 30 -51 7 53 -49 37 47 - 66 0 0 -50 9 59 3 52 21 10 292 -59 -50 24 18 -49 55 42 -50 55 17 -49 24 53 - 67 0 0 -49 56 45 3 52 19 11 292 -59 -50 11 6 -49 42 24 -50 42 12 -49 11 30 - 68 0 0 -49 43 1 3 52 17 11 293 -59 -49 57 26 -49 28 38 -50 28 37 -48 57 37 - 69 0 0 -49 28 48 3 52 15 12 294 -59 -49 43 15 -49 14 22 -50 14 34 -48 43 14 - 70 0 0 -49 14 4 3 52 13 13 295 -59 -49 28 35 -48 59 35 -50 0 0 -48 28 21 - 71 0 0 -48 58 50 3 52 11 13 296 -59 -49 13 24 -48 44 18 -49 44 56 -48 12 57 - 72 0 0 -48 43 5 3 52 9 14 296 -59 -48 57 42 -48 28 29 -49 29 21 -47 57 1 - 73 0 0 -48 26 49 3 52 7 15 297 -59 -48 41 29 -48 12 9 -49 13 15 -47 40 34 - 74 0 0 -48 10 0 3 52 4 16 298 -59 -48 24 44 -47 55 18 -48 56 38 -47 23 35 - 75 0 0 -47 52 40 3 52 1 16 299 -59 -48 7 27 -47 37 54 -48 39 28 -47 6 4 - 76 0 0 -47 34 46 3 51 58 17 299 -59 -47 49 37 -47 19 57 -48 21 46 -46 47 59 - 77 0 0 -47 16 20 3 51 55 18 300 -59 -47 31 15 -47 1 27 -48 3 32 -46 29 21 - 78 0 0 -46 57 20 3 51 52 19 301 -59 -47 12 18 -46 42 23 -47 44 43 -46 10 9 - 79 0 0 -46 37 46 3 51 49 19 302 -58 -46 52 48 -46 22 45 -47 25 21 -45 50 23 - 80 0 0 -46 17 37 3 51 45 20 302 -58 -46 32 43 -46 2 33 -47 5 25 -45 30 3 - 81 0 0 -45 56 54 3 51 42 21 303 -58 -46 12 4 -45 41 45 -46 44 54 -45 9 7 - 82 0 0 -45 35 35 3 51 38 22 304 -58 -45 50 49 -45 20 22 -46 23 48 -44 47 36 - 83 0 0 -45 13 40 3 51 34 22 305 -57 -45 28 58 -44 58 24 -46 2 6 -44 25 28 - 84 0 0 -44 51 10 3 51 30 23 306 -57 -45 6 32 -44 35 49 -45 39 48 -44 2 45 - 85 0 0 -44 28 2 3 51 25 24 306 -57 -44 43 28 -44 12 37 -45 16 54 -43 39 24 - 86 0 0 -44 4 17 3 51 21 25 307 -57 -44 19 48 -43 48 48 -44 53 22 -43 15 26 - 87 0 0 -43 39 55 3 51 16 26 308 -56 -43 55 30 -43 24 22 -44 29 14 -42 50 51 - 88 0 0 -43 14 55 3 51 11 27 309 -56 -43 30 34 -42 59 18 -44 4 27 -42 25 37 - 89 0 0 -42 49 17 3 51 6 27 309 -56 -43 5 0 -42 33 35 -43 39 3 -41 59 46 - 90 0 0 -42 23 0 3 51 0 28 310 -55 -42 38 48 -42 7 14 -43 12 59 -41 33 15 - 91 0 0 -41 56 4 3 50 55 29 311 -55 -42 11 56 -41 40 14 -42 46 17 -41 6 6 - 92 0 0 -41 28 29 3 50 49 30 312 -54 -41 44 25 -41 12 34 -42 18 56 -40 38 17 - 93 0 0 -41 0 14 3 50 43 31 312 -54 -41 16 15 -40 44 15 -41 50 55 -40 9 49 - 94 0 0 -40 31 20 3 50 36 32 313 -53 -40 47 25 -40 15 16 -41 22 15 -39 40 40 - 95 0 0 -40 1 45 3 50 30 33 314 -53 -40 17 55 -39 45 38 -40 52 54 -39 10 52 - 96 0 0 -39 31 31 3 50 23 34 315 -52 -39 47 44 -39 15 18 -40 22 53 -38 40 24 - 97 0 0 -39 0 36 3 50 16 35 316 -52 -39 16 54 -38 44 19 -39 52 12 -38 9 15 - 98 0 0 -38 29 0 3 50 8 36 316 -51 -38 45 22 -38 12 39 -39 20 50 -37 37 26 - 99 0 0 -37 56 44 3 50 1 36 317 -50 -38 13 11 -37 40 19 -38 48 48 -37 4 57 -100 0 0 -37 23 47 3 49 53 37 318 -50 -37 40 18 -37 7 18 -38 16 4 -36 31 47 -101 0 0 -36 50 10 3 49 44 38 319 -49 -37 6 45 -36 33 37 -37 42 41 -35 57 57 -102 0 0 -36 15 53 3 49 36 39 320 -48 -36 32 32 -35 59 15 -37 8 36 -35 23 26 -103 0 0 -35 40 55 3 49 27 40 320 -48 -35 57 39 -35 24 14 -36 33 52 -34 48 16 -104 0 0 -35 5 18 3 49 18 41 321 -47 -35 22 5 -34 48 32 -35 58 27 -34 12 26 -105 0 0 -34 29 0 3 49 9 42 322 -46 -34 45 52 -34 12 11 -35 22 22 -33 35 56 -106 0 0 -33 52 4 3 48 59 43 323 -45 -34 8 59 -33 35 11 -34 45 37 -32 58 48 -107 0 0 -33 14 29 3 48 49 44 324 -45 -33 31 27 -32 57 32 -34 8 14 -32 21 1 -108 0 0 -32 36 15 3 48 39 45 325 -44 -32 53 17 -32 19 15 -33 30 12 -31 42 36 -109 0 0 -31 57 24 3 48 29 46 326 -43 -32 14 30 -31 40 20 -32 51 32 -31 3 34 -110 0 0 -31 17 56 3 48 18 47 327 -42 -31 35 5 -31 0 48 -32 12 14 -30 23 56 -111 0 0 -30 37 51 3 48 7 49 328 -41 -30 55 4 -30 20 41 -31 32 20 -29 43 41 -112 0 0 -29 57 12 3 47 55 50 329 -40 -30 14 27 -29 39 58 -30 51 50 -29 2 52 -113 0 0 -29 15 58 3 47 44 51 330 -39 -29 33 16 -28 58 42 -30 10 45 -28 21 29 -114 0 0 -28 34 11 3 47 32 52 331 -38 -28 51 32 -28 16 52 -29 29 6 -27 39 34 -115 0 0 -27 51 52 3 47 19 53 332 -37 -28 9 15 -27 34 30 -28 46 55 -26 57 7 -116 0 0 -27 9 2 3 47 7 54 333 -36 -27 26 27 -26 51 38 -28 4 13 -26 14 10 -117 0 0 -26 25 43 3 46 54 55 334 -35 -26 43 10 -26 8 17 -27 21 0 -25 30 44 -118 0 0 -25 41 55 3 46 41 56 335 -34 -25 59 25 -25 24 28 -26 37 19 -24 46 51 -119 0 0 -24 57 42 3 46 27 57 337 -33 -25 15 13 -24 40 12 -25 53 11 -24 2 32 -120 0 0 -24 13 3 3 46 14 58 338 -32 -24 30 36 -23 55 32 -25 8 37 -23 17 49 -121 0 0 -23 28 2 3 46 0 59 340 -31 -23 45 36 -23 10 30 -24 23 40 -22 32 44 -122 0 0 -22 42 39 3 45 46 60 341 -30 -23 0 14 -22 25 6 -23 38 20 -21 47 18 -123 0 0 -21 56 57 3 45 31 61 343 -29 -22 14 33 -21 39 23 -22 52 41 -21 1 34 -124 0 0 -21 10 58 3 45 16 62 345 -28 -21 28 34 -20 53 23 -22 6 43 -20 15 33 -125 0 0 -20 24 43 3 45 2 63 347 -27 -20 42 19 -20 7 8 -21 20 29 -19 29 17 -126 0 0 -19 38 15 3 44 46 64 349 -26 -19 55 51 -19 20 40 -20 34 1 -18 42 49 -127 0 0 -18 51 35 3 44 31 65 351 -24 -19 9 12 -18 34 1 -19 47 21 -17 56 10 -128 0 0 -18 4 47 3 44 16 66 353 -23 -18 22 23 -17 47 13 -19 0 31 -17 9 24 -129 0 0 -17 17 52 3 44 0 67 355 -22 -17 35 27 -17 0 19 -18 13 34 -16 22 31 -130 0 0 -16 30 53 3 43 44 68 358 -21 -16 48 27 -16 13 20 -17 26 31 -15 35 34 -131 0 0 -15 43 51 3 43 28 69 1 -20 -16 1 24 -15 26 20 -16 39 25 -14 48 37 -132 0 0 -14 56 49 3 43 12 69 4 -18 -15 14 21 -14 39 20 -15 52 19 -14 1 40 -133 0 0 -14 9 50 3 42 56 70 7 -17 -14 27 19 -13 52 22 -15 5 14 -13 14 46 -134 0 0 -13 22 55 3 42 39 71 11 -16 -13 40 23 -13 5 29 -14 18 13 -12 27 57 -135 0 0 -12 36 7 3 42 23 71 14 -15 -12 53 33 -12 18 43 -13 31 19 -11 41 16 -136 0 0 -11 49 28 3 42 7 72 18 -14 -12 6 52 -11 32 7 -12 44 32 -10 54 45 -137 0 0 -11 3 1 3 41 50 72 22 -12 -11 20 22 -10 45 42 -11 57 57 -10 8 26 -138 0 0 -10 16 47 3 41 34 72 26 -11 -10 34 5 - 9 59 31 -11 11 34 - 9 22 21 -139 0 0 - 9 30 49 3 41 17 72 30 -10 - 9 48 4 - 9 13 36 -10 25 27 - 8 36 32 -140 0 0 - 8 45 9 3 41 0 72 35 -9 - 9 2 21 - 8 27 59 - 9 39 36 - 7 51 2 -141 0 0 - 7 59 48 3 40 44 72 39 -7 - 8 16 57 - 7 42 42 - 8 54 5 - 7 5 52 -142 0 0 - 7 14 50 3 40 27 72 43 -6 - 7 31 54 - 6 57 47 - 8 8 55 - 6 21 4 -143 0 0 - 6 30 15 3 40 11 72 47 -5 - 6 47 16 - 6 13 15 - 7 24 8 - 5 36 41 -144 0 0 - 5 46 5 3 39 55 72 51 -4 - 6 3 2 - 5 29 10 - 6 39 46 - 4 52 43 -145 0 0 - 5 2 22 3 39 38 71 55 -2 - 5 19 16 - 4 45 31 - 5 55 51 - 4 9 13 -146 0 0 - 4 19 9 3 39 22 71 58 -1 - 4 35 58 - 4 2 21 - 5 12 25 - 3 26 12 Uncertainty in time = +/- 8 secs [Prediction of 2008 May 8.0] Data for the target star ------------------------ * name: TYC 0260-00499-1 * constellation : Sextans * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 10 45 10.1554 DE: +05 52 02.461 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .031, .020 ) * V mag [mag]: 10.0 * B mag [mag]: 11.2 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1242) Zambesia approx. diameter [km]: 48 approx. diameter ["]: .025 distance from Earth [AU]: 2.66600 * orbital information: orbit source: Preston date of fit: 2008 May 07 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 740 number of rejected observations: 79 time covered by the observations: 1936 Apr 17 - 2008 May 06 1 sigma uncertainty ellipse (major, minor, PA): 0.024, 0.016, 125° remarks: * orbital elements for (1242) Zambesia : Mean anomaly = 119.58964493 deg Arg. of pericenter = 53.03264251 deg Long. of node = 350.06264976 deg Inclination = 10.17872201 deg Eccentricity = 0.19108487 Semimajor axis = 2.73456994 AU Perihelion dist = 2.21203499 AU Mag: H = 10.26, G = 0.15 Epoch of elements : MJD 54604.15300000 TDT (2008 May 18.153) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 May 18 1242 Zambesia 3h 40.9m UT 10.0 10 45 10.155 5 52 2.46TYC 0260-00499-1 11.2 15.6 48 5.5 2.666 0.891 -9.37 -130.1464 5.870 123.88 19.62 3.6824 -0.17502 -0.24616 4.02718 -2.84028 0.00511 -0.00203 2000 118.6844702008 514.00000 53.032643350.062650 10.1787220.19108487 2.7345699 2.212035010.1 5.00.15 RATE 2.1795690 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.038 0.025 103 2.08 0.027 0 54594.5020080518_0499-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 May 08, 03:30 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org