IOTA/IOTA-ES occultation update for (409) Aspasia / TYC 0786-00888-1 event on 2008 May 20, 11:44 UT Visible from SW Australia Summary ------- On 2008 May 20 UT, the 162 km diameter asteroid (409) Aspasia will occult a 9.5 mag star in the constellation Canis Minor for observers along a path across SW Australia. In the case of an occultation, the combined light of the asteroid and the star will drop by 3.4 mag to 12.9 mag (the magnitude of the asteroid) for at most 4.9 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: 98 * date and approx. time of event: 2008 May 20, 11:45 - 2008 May 20, 11:46 UT * magnitude of target star: 9.5 * magnitude drop [mag]: 3.4 * estimated maximum duration [s]: 4.9 * Moon: 100 % sunlit, 127° distance * Sun: 56° distance * rough path description: SW Australia The occultation path -------------------- * approximate projected width [km]: 199 * 1 sigma uncertainty interval [path widths]: +/- 0.37 * 1 sigma uncertainty interval [seconds]: +/- 1.5 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .024 +/- .028) * 1 sigma uncertainty ellipse (major, minor, PA): ( .028", .024", 1° ) * approx speed of asteroid's shadow [km/s]: 33.2356 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 0786-00888-1 by 409 Aspasia on 2008 May 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 82 0 0 -27 25 21 11 45 10 46 330 0 -28 20 59 -26 30 22 -29 2 36 -25 50 4 83 0 0 -27 38 0 11 45 12 45 329 -1 -28 33 41 -26 42 59 -29 15 19 -26 2 39 84 0 0 -27 50 49 11 45 15 44 327 -2 -28 46 32 -26 55 45 -29 28 13 -26 15 24 85 0 0 -28 3 48 11 45 18 44 326 -3 -28 59 33 -27 8 41 -29 41 15 -26 28 18 86 0 0 -28 16 55 11 45 20 43 325 -4 -29 12 43 -27 21 46 -29 54 27 -26 41 21 87 0 0 -28 30 11 11 45 23 42 324 -5 -29 26 1 -27 35 0 -30 7 47 -26 54 34 88 0 0 -28 43 35 11 45 25 42 323 -5 -29 39 28 -27 48 22 -30 21 15 -27 7 54 89 0 0 -28 57 8 11 45 28 41 322 -6 -29 53 3 -28 1 52 -30 34 52 -27 21 23 90 0 0 -29 10 48 11 45 30 40 321 -7 -30 6 45 -28 15 30 -30 48 36 -27 34 59 91 0 0 -29 24 36 11 45 33 39 320 -8 -30 20 35 -28 29 16 -31 2 28 -27 48 43 92 0 0 -29 38 30 11 45 35 39 319 -9 -30 34 32 -28 43 8 -31 16 26 -28 2 34 93 0 0 -29 52 32 11 45 37 38 319 -10 -30 48 35 -28 57 7 -31 30 31 -28 16 32 94 0 0 -30 6 39 11 45 40 37 318 -11 -31 2 45 -29 11 13 -31 44 42 -28 30 36 95 0 0 -30 20 53 11 45 42 36 317 -12 -31 17 1 -29 25 25 -31 59 0 -28 44 47 96 0 0 -30 35 12 11 45 44 36 316 -13 -31 31 22 -29 39 43 -32 13 23 -28 59 3 97 0 0 -30 49 37 11 45 46 35 315 -14 -31 45 49 -29 54 6 -32 27 51 -29 13 24 98 0 0 -31 4 7 11 45 48 34 314 -15 -32 0 20 -30 8 34 -32 42 24 -29 27 51 99 0 0 -31 18 42 11 45 50 33 313 -15 -32 14 57 -30 23 6 -32 57 1 -29 42 23 100 0 0 -31 33 20 11 45 52 32 313 -16 -32 29 37 -30 37 44 -33 11 43 -29 56 59 101 0 0 -31 48 3 11 45 54 32 312 -17 -32 44 22 -30 52 25 -33 26 29 -30 11 39 102 0 0 -32 2 50 11 45 56 31 311 -18 -32 59 10 -31 7 10 -33 41 18 -30 26 23 103 0 0 -32 17 39 11 45 58 30 310 -19 -33 14 1 -31 21 58 -33 56 10 -30 41 10 104 0 0 -32 32 32 11 46 0 29 310 -20 -33 28 55 -31 36 49 -34 11 5 -30 56 0 105 0 0 -32 47 27 11 46 1 28 309 -21 -33 43 51 -31 51 43 -34 26 3 -31 10 53 106 0 0 -33 2 24 11 46 3 28 308 -22 -33 58 50 -32 6 39 -34 41 2 -31 25 48 107 0 0 -33 17 23 11 46 5 27 307 -23 -34 13 50 -32 21 37 -34 56 3 -31 40 46 108 0 0 -33 32 24 11 46 6 26 307 -23 -34 28 52 -32 36 37 -35 11 6 -31 55 45 109 0 0 -33 47 26 11 46 8 25 306 -24 -34 43 55 -32 51 38 -35 26 10 -32 10 45 110 0 0 -34 2 29 11 46 9 24 305 -25 -34 58 58 -33 6 40 -35 41 14 -32 25 46 111 0 0 -34 17 32 11 46 11 24 305 -26 -35 14 2 -33 21 42 -35 56 19 -32 40 48 112 0 0 -34 32 35 11 46 12 23 304 -27 -35 29 6 -33 36 45 -36 11 23 -32 55 50 113 0 0 -34 47 38 11 46 14 22 303 -28 -35 44 10 -33 51 47 -36 26 28 -33 10 52 114 0 0 -35 2 41 11 46 15 21 303 -29 -35 59 13 -34 6 50 -36 41 31 -33 25 54 115 0 0 -35 17 43 11 46 16 20 302 -29 -36 14 16 -34 21 51 -36 56 34 -33 40 55 116 0 0 -35 32 44 11 46 17 19 301 -30 -36 29 17 -34 36 51 -37 11 35 -33 55 55 117 0 0 -35 47 43 11 46 18 19 301 -31 -36 44 16 -34 51 50 -37 26 34 -34 10 54 118 0 0 -36 2 40 11 46 20 18 300 -32 -36 59 13 -35 6 47 -37 41 32 -34 25 51 119 0 0 -36 17 35 11 46 21 17 299 -33 -37 14 9 -35 21 42 -37 56 27 -34 40 46 120 0 0 -36 32 28 11 46 22 16 299 -33 -37 29 1 -35 36 35 -38 11 20 -34 55 39 121 0 0 -36 47 18 11 46 23 15 298 -34 -37 43 51 -35 51 25 -38 26 10 -35 10 29 122 0 0 -37 2 5 11 46 23 14 297 -35 -37 58 38 -36 6 12 -38 40 56 -35 25 16 123 0 0 -37 16 48 11 46 24 14 297 -36 -38 13 21 -36 20 56 -38 55 39 -35 40 0 124 0 0 -37 31 28 11 46 25 13 296 -37 -38 28 0 -36 35 36 -39 10 18 -35 54 41 125 0 0 -37 46 4 11 46 26 12 296 -37 -38 42 35 -36 50 12 -39 24 53 -36 9 17 126 0 0 -38 0 35 11 46 26 11 295 -38 -38 57 6 -37 4 44 -39 39 23 -36 23 50 127 0 0 -38 15 2 11 46 27 10 294 -39 -39 11 33 -37 19 12 -39 53 49 -36 38 18 128 0 0 -38 29 24 11 46 28 10 294 -40 -39 25 54 -37 33 35 -40 8 10 -36 52 42 129 0 0 -38 43 42 11 46 28 9 293 -41 -39 40 10 -37 47 53 -40 22 26 -37 7 0 130 0 0 -38 57 53 11 46 29 8 292 -41 -39 54 21 -38 2 6 -40 36 36 -37 21 14 131 0 0 -39 12 0 11 46 29 7 292 -42 -40 8 27 -38 16 13 -40 50 40 -37 35 22 132 0 0 -39 26 0 11 46 29 6 291 -43 -40 22 26 -38 30 15 -41 4 39 -37 49 24 133 0 0 -39 39 54 11 46 30 5 290 -44 -40 36 19 -38 44 10 -41 18 31 -38 3 20 134 0 0 -39 53 42 11 46 30 5 290 -44 -40 50 5 -38 57 59 -41 32 16 -38 17 10 135 0 0 -40 7 24 11 46 30 4 289 -45 -41 3 45 -39 11 42 -41 45 55 -38 30 54 136 0 0 -40 20 58 11 46 31 3 289 -46 -41 17 19 -39 25 18 -41 59 27 -38 44 31 137 0 0 -40 34 26 11 46 31 2 288 -46 -41 30 45 -39 38 47 -42 12 52 -38 58 1 138 0 0 -40 47 46 11 46 31 1 287 -47 -41 44 3 -39 52 9 -42 26 10 -39 11 24 139 0 0 -41 0 59 11 46 31 1 287 -48 -41 57 15 -40 5 24 -42 39 20 -39 24 40 Uncertainty in time = +/- 2 secs [Prediction of 2008 May 17.0] Data for the target star ------------------------ * name: TYC 0786-00888-1 * constellation : Canis Minor * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 07 42 13.3119 DE: +12 02 06.046 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .023, .027 ) * V mag [mag]: 9.5 * B mag [mag]: 11.1 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (409) Aspasia approx. diameter [km]: 162 approx. diameter ["]: .074 distance from Earth [AU]: 3.02200 * orbital information: orbit source: Preston date of fit: 2008 May 17 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 1171 number of rejected observations: 140 time covered by the observations: 1902 Jul 07 - 2008 May 14 1 sigma uncertainty ellipse (major, minor, PA): 0.007, 0.006, 104° remarks: * orbital elements for (409) Aspasia : Mean anomaly = 267.62152983 deg Arg. of pericenter = 352.76047218 deg Long. of node = 242.35931460 deg Inclination = 11.24289290 deg Eccentricity = 0.07047519 Semimajor axis = 2.57665785 AU Perihelion dist = 2.39506740 AU Mag: H = 7.65, G = 0.29 Epoch of elements : MJD 54606.48900000 TDT (2008 May 20.489) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 May 20 409 Aspasia 11h 43.9m UT 9.5 7 42 13.312 12 2 6.05TYC 0786-00888-1 11.1 12.9 162 4.9 3.022 3.696 -6.42 61.0738 12.036 3.16 20.12 11.7318 -0.06878 -0.57424 18.62916 -2.20424 0.00439 -0.00128 2000 266.0752192008 514.00000352.760472242.359315 11.2428930.07047519 2.5766579 2.3950674 7.6 5.00.29 RATE 2.3829720 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.028 0.024 1 1.37 0.028 0 54603.5020080520_0888-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 May 17, 17:15 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org