IOTA/IOTA-ES occultation update for (138) Tolosa / TYC 6820-00394-1 event on 2012 Aug 29, 04:44 UT Visible from Chile Summary ------- On 2012 Aug 29 UT, the 52 km diameter asteroid (138) Tolosa will occult a 9.9 mag star in the constellation Ophiuchus for observers along a path across Chile. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.8 mag to 12.6 mag (the magnitude of the asteroid) for at most 4.3 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: 85 * date and approx. time of event: 2012 Aug 29, 04:41 - 2012 Aug 29, 04:52 UT * geocentric midpoint of event [JD]: 2456168.69732917 * magnitude of target star: 9.9 * magnitude drop [mag]: 2.8 * estimated maximum duration [s]: 4.3 * Moon: 93 % sunlit, 46° distance * Sun: 104° distance * rough path description: Chile The occultation path -------------------- * approximate projected width [km]: 53 * 1 sigma uncertainty interval [path widths]: +/- 0.59 * 1 sigma uncertainty interval [seconds]: +/- 3.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .035 +/- .027) * 1 sigma uncertainty ellipse (major, minor, PA): ( .035", .027", 92° ) * approx speed of asteroid's shadow [km/s]: 11.9253 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6820-00394-1 by 138 Tolosa on 2012 Aug 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 -167 0 0 -36 22 14 4 41 58 72 63 0 -36 36 52 -36 7 36 -36 54 9 -35 50 22 -166 0 0 -36 31 32 4 42 6 72 61 -1 -36 46 8 -36 16 56 -37 3 24 -35 59 43 -165 0 0 -36 40 25 4 42 13 73 58 -2 -36 55 0 -36 25 50 -37 12 14 -36 8 39 -164 0 0 -36 48 53 4 42 21 73 56 -3 -37 3 27 -36 34 19 -37 20 39 -36 17 10 -163 0 0 -36 56 56 4 42 29 74 53 -3 -37 11 29 -36 42 24 -37 28 40 -36 25 16 -162 0 0 -37 4 35 4 42 36 75 50 -4 -37 19 7 -36 50 4 -37 36 16 -36 32 57 -161 0 0 -37 11 49 4 42 44 75 47 -5 -37 26 19 -36 57 19 -37 43 28 -36 40 13 -160 0 0 -37 18 38 4 42 52 76 44 -6 -37 33 8 -37 4 9 -37 50 15 -36 47 5 -159 0 0 -37 25 3 4 42 59 76 41 -7 -37 39 31 -37 10 35 -37 56 37 -36 53 32 -158 0 0 -37 31 3 4 43 7 76 37 -8 -37 45 30 -37 16 36 -38 2 35 -36 59 34 -157 0 0 -37 36 38 4 43 14 77 34 -8 -37 51 5 -37 22 12 -38 8 9 -37 5 11 -156 0 0 -37 41 50 4 43 22 77 30 -9 -37 56 16 -37 27 24 -38 13 18 -37 10 24 -155 0 0 -37 46 36 4 43 30 78 25 -10 -38 1 2 -37 32 12 -38 18 3 -37 15 12 -154 0 0 -37 50 59 4 43 37 78 21 -11 -38 5 23 -37 36 35 -38 22 24 -37 19 36 -153 0 0 -37 54 57 4 43 45 78 17 -12 -38 9 21 -37 40 33 -38 26 21 -37 23 36 -152 0 0 -37 58 30 4 43 53 78 12 -12 -38 12 54 -37 44 8 -38 29 54 -37 27 11 -151 0 0 -38 1 40 4 44 0 78 8 -13 -38 16 3 -37 47 18 -38 33 2 -37 30 21 -150 0 0 -38 4 25 4 44 8 78 3 -14 -38 18 48 -37 50 3 -38 35 46 -37 33 7 -149 0 0 -38 6 46 4 44 15 78 358 -15 -38 21 8 -37 52 25 -38 38 6 -37 35 29 -148 0 0 -38 8 43 4 44 23 78 354 -16 -38 23 5 -37 54 22 -38 40 3 -37 37 27 -147 0 0 -38 10 16 4 44 31 78 349 -17 -38 24 37 -37 55 55 -38 41 35 -37 39 0 -146 0 0 -38 11 24 4 44 38 78 345 -17 -38 25 46 -37 57 4 -38 42 43 -37 40 9 -145 0 0 -38 12 9 4 44 46 78 340 -18 -38 26 30 -37 57 48 -38 43 27 -37 40 54 -144 0 0 -38 12 29 4 44 53 77 336 -19 -38 26 50 -37 58 9 -38 43 47 -37 41 14 -143 0 0 -38 12 25 4 45 1 77 332 -20 -38 26 47 -37 58 5 -38 43 44 -37 41 10 -142 0 0 -38 11 57 4 45 8 76 329 -21 -38 26 19 -37 57 37 -38 43 16 -37 40 42 -141 0 0 -38 11 5 4 45 16 76 325 -21 -38 25 27 -37 56 45 -38 42 24 -37 39 50 -140 0 0 -38 9 49 4 45 23 76 322 -22 -38 24 11 -37 55 28 -38 41 9 -37 38 33 -139 0 0 -38 8 9 4 45 31 75 319 -23 -38 22 31 -37 53 48 -38 39 29 -37 36 52 -138 0 0 -38 6 5 4 45 38 75 316 -24 -38 20 27 -37 51 43 -38 37 25 -37 34 47 -137 0 0 -38 3 36 4 45 46 74 313 -25 -38 17 59 -37 49 14 -38 34 58 -37 32 18 -136 0 0 -38 0 43 4 45 53 74 310 -25 -38 15 6 -37 46 21 -38 32 6 -37 29 24 -135 0 0 -37 57 26 4 46 1 73 308 -26 -38 11 50 -37 43 3 -38 28 50 -37 26 6 -134 0 0 -37 53 45 4 46 8 72 305 -27 -38 8 10 -37 39 22 -38 25 10 -37 22 24 -133 0 0 -37 49 40 4 46 16 72 303 -28 -38 4 5 -37 35 16 -38 21 6 -37 18 17 -132 0 0 -37 45 10 4 46 23 71 301 -29 -37 59 36 -37 30 45 -38 16 38 -37 13 46 -131 0 0 -37 40 16 4 46 30 70 299 -30 -37 54 43 -37 25 51 -38 11 46 -37 8 50 -130 0 0 -37 34 58 4 46 38 70 297 -30 -37 49 25 -37 20 32 -38 6 29 -37 3 30 -129 0 0 -37 29 15 4 46 45 69 295 -31 -37 43 43 -37 14 48 -38 0 49 -36 57 45 -128 0 0 -37 23 8 4 46 52 68 294 -32 -37 37 37 -37 8 40 -37 54 44 -36 51 36 -127 0 0 -37 16 37 4 47 0 68 292 -33 -37 31 7 -37 2 7 -37 48 14 -36 45 2 -126 0 0 -37 9 41 4 47 7 67 290 -34 -37 24 12 -36 55 10 -37 41 21 -36 38 4 -125 0 0 -37 2 20 4 47 14 66 289 -34 -37 16 52 -36 47 48 -37 34 2 -36 30 41 -124 0 0 -36 54 35 4 47 22 65 287 -35 -37 9 8 -36 40 2 -37 26 20 -36 22 53 -123 0 0 -36 46 25 4 47 29 65 286 -36 -37 0 59 -36 31 51 -37 18 12 -36 14 41 -122 0 0 -36 37 50 4 47 36 64 285 -37 -36 52 26 -36 23 15 -37 9 41 -36 6 3 -121 0 0 -36 28 51 4 47 43 63 283 -38 -36 43 28 -36 14 14 -37 0 44 -35 57 1 -120 0 0 -36 19 27 4 47 50 62 282 -39 -36 34 5 -36 4 49 -36 51 23 -35 47 34 -119 0 0 -36 9 38 4 47 58 62 281 -39 -36 24 18 -35 54 58 -36 41 37 -35 37 42 -118 0 0 -35 59 24 4 48 5 61 280 -40 -36 14 6 -35 44 43 -36 31 27 -35 27 25 -117 0 0 -35 48 45 4 48 12 60 278 -41 -36 3 28 -35 34 3 -36 20 51 -35 16 43 -116 0 0 -35 37 41 4 48 19 59 277 -42 -35 52 26 -35 22 58 -36 9 51 -35 5 35 -115 0 0 -35 26 13 4 48 26 58 276 -43 -35 40 59 -35 11 27 -35 58 26 -34 54 3 -114 0 0 -35 14 19 4 48 33 58 275 -44 -35 29 7 -34 59 32 -35 46 36 -34 42 6 -113 0 0 -35 2 0 4 48 40 57 274 -45 -35 16 50 -34 47 11 -35 34 21 -34 29 43 -112 0 0 -34 49 16 4 48 47 56 273 -45 -35 4 8 -34 34 26 -35 21 41 -34 16 56 -111 0 0 -34 36 7 4 48 54 55 272 -46 -34 51 0 -34 21 15 -35 8 35 -34 3 43 -110 0 0 -34 22 33 4 49 0 54 271 -47 -34 37 28 -34 7 39 -34 55 5 -33 50 4 -109 0 0 -34 8 34 4 49 7 53 270 -48 -34 23 30 -33 53 37 -34 41 10 -33 36 1 -108 0 0 -33 54 9 4 49 14 53 270 -49 -34 9 8 -33 39 11 -34 26 50 -33 21 32 -107 0 0 -33 39 19 4 49 21 52 269 -50 -33 54 20 -33 24 19 -34 12 4 -33 6 39 -106 0 0 -33 24 5 4 49 27 51 268 -51 -33 39 7 -33 9 3 -33 56 54 -32 51 20 -105 0 0 -33 8 25 4 49 34 50 267 -51 -33 23 29 -32 53 21 -33 41 18 -32 35 35 -104 0 0 -32 52 20 4 49 40 49 266 -52 -33 7 26 -32 37 14 -33 25 17 -32 19 26 -103 0 0 -32 35 50 4 49 47 48 265 -53 -32 50 58 -32 20 42 -33 8 52 -32 2 52 -102 0 0 -32 18 54 4 49 53 47 265 -54 -32 34 5 -32 3 45 -32 52 1 -31 45 52 -101 0 0 -32 1 34 4 50 0 46 264 -55 -32 16 47 -31 46 23 -32 34 45 -31 28 28 -100 0 0 -31 43 49 4 50 6 46 263 -56 -31 59 4 -31 28 36 -32 17 5 -31 10 38 - 99 0 0 -31 25 40 4 50 12 45 262 -57 -31 40 57 -31 10 24 -31 59 0 -30 52 24 - 98 0 0 -31 7 5 4 50 19 44 262 -58 -31 22 24 -30 51 47 -31 40 30 -30 33 45 - 97 0 0 -30 48 6 4 50 25 43 261 -59 -31 3 27 -30 32 46 -31 21 35 -30 14 41 - 96 0 0 -30 28 43 4 50 31 42 260 -59 -30 44 6 -30 13 21 -31 2 16 -29 55 13 - 95 0 0 -30 8 55 4 50 37 41 260 -60 -30 24 20 -29 53 31 -30 42 33 -29 35 21 - 94 0 0 -29 48 43 4 50 43 40 259 -61 -30 4 10 -29 33 17 -30 22 26 -29 15 5 - 93 0 0 -29 28 7 4 50 48 39 258 -62 -29 43 36 -29 12 39 -30 1 54 -28 54 24 - 92 0 0 -29 7 7 4 50 54 38 258 -63 -29 22 39 -28 51 37 -29 40 59 -28 33 20 - 91 0 0 -28 45 44 4 51 0 37 257 -64 -29 1 17 -28 30 11 -29 19 40 -28 11 52 - 90 0 0 -28 23 57 4 51 5 36 257 -65 -28 39 33 -28 8 23 -28 57 58 -27 50 1 - 89 0 0 -28 1 47 4 51 11 35 256 -66 -28 17 25 -27 46 11 -28 35 52 -27 27 47 - 88 0 0 -27 39 15 4 51 16 34 255 -67 -27 54 54 -27 23 36 -28 13 24 -27 5 10 - 87 0 0 -27 16 19 4 51 21 33 255 -67 -27 32 1 -27 0 39 -27 50 33 -26 42 10 - 86 0 0 -26 53 2 4 51 26 32 254 -68 -27 8 46 -26 37 20 -27 27 20 -26 18 49 - 85 0 0 -26 29 23 4 51 31 31 254 -69 -26 45 8 -26 13 38 -27 3 45 -25 55 5 - 84 0 0 -26 5 22 4 51 36 30 253 -70 -26 21 9 -25 49 35 -26 39 48 -25 31 0 - 83 0 0 -25 41 0 4 51 41 29 253 -71 -25 56 49 -25 25 12 -26 15 30 -25 6 34 - 82 0 0 -25 16 17 4 51 46 28 252 -72 -25 32 8 -25 0 27 -25 50 51 -24 41 47 - 81 0 0 -24 51 14 4 51 50 27 252 -73 -25 7 6 -24 35 22 -25 25 52 -24 16 40 - 80 0 0 -24 25 51 4 51 55 26 251 -73 -24 41 45 -24 9 57 -25 0 32 -23 51 14 - 79 0 0 -24 0 8 4 51 59 25 251 -74 -24 16 4 -23 44 13 -24 34 53 -23 25 27 - 78 0 0 -23 34 7 4 52 3 24 250 -75 -23 50 4 -23 18 10 -24 8 55 -22 59 22 - 77 0 0 -23 7 47 4 52 7 23 250 -76 -23 23 46 -22 51 48 -23 42 39 -22 32 59 - 76 0 0 -22 41 9 4 52 11 22 249 -76 -22 57 9 -22 25 9 -23 16 4 -22 6 18 - 75 0 0 -22 14 14 4 52 14 21 249 -77 -22 30 16 -21 58 13 -22 49 12 -21 39 20 - 74 0 0 -21 47 2 4 52 18 20 249 -77 -22 3 5 -21 30 59 -22 22 3 -21 12 5 - 73 0 0 -21 19 34 4 52 21 19 248 -78 -21 35 38 -21 3 30 -21 54 38 -20 44 34 - 72 0 0 -20 51 50 4 52 25 18 248 -78 -21 7 56 -20 35 45 -21 26 57 -20 16 48 - 71 0 0 -20 23 52 4 52 28 17 247 -79 -20 39 59 -20 7 46 -20 59 1 -19 48 47 - 70 0 0 -19 55 39 4 52 31 16 247 -79 -20 11 47 -19 39 32 -20 30 51 -19 20 32 - 69 0 0 -19 27 13 4 52 33 15 247 -79 -19 43 22 -19 11 5 -20 2 27 -18 52 4 - 68 0 0 -18 58 34 4 52 36 14 246 -79 -19 14 44 -18 42 25 -19 33 50 -18 23 23 - 67 0 0 -18 29 42 4 52 38 13 246 -79 -18 45 53 -18 13 33 -19 5 0 -17 54 30 - 66 0 0 -18 0 40 4 52 40 12 246 -79 -18 16 51 -17 44 29 -18 35 59 -17 25 25 - 65 0 0 -17 31 27 4 52 42 11 245 -79 -17 47 39 -17 15 15 -18 6 48 -16 56 11 - 64 0 0 -17 2 4 4 52 44 10 245 -78 -17 18 17 -16 45 52 -17 37 26 -16 26 46 - 63 0 0 -16 32 32 4 52 46 9 245 -78 -16 48 45 -16 16 19 -17 7 55 -15 57 13 - 62 0 0 -16 2 51 4 52 47 7 245 -77 -16 19 5 -15 46 38 -16 38 16 -15 27 32 - 61 0 0 -15 33 3 4 52 48 6 244 -77 -15 49 18 -15 16 50 -16 8 29 -14 57 43 - 60 0 0 -15 3 9 4 52 50 5 244 -76 -15 19 24 -14 46 56 -15 38 35 -14 27 48 - 59 0 0 -14 33 9 4 52 50 4 244 -75 -14 49 23 -14 16 55 -15 8 35 -13 57 48 - 58 0 0 -14 3 3 4 52 51 3 243 -75 -14 19 18 -13 46 50 -14 38 30 -13 27 42 - 57 0 0 -13 32 54 4 52 52 2 243 -74 -13 49 9 -13 16 40 -14 8 21 -12 57 33 - 56 0 0 -13 2 41 4 52 52 1 243 -73 -13 18 56 -12 46 28 -13 38 8 -12 27 20 Uncertainty in time = +/- 3 secs Prediction of 2012 Aug 26.0 Data for the target star ------------------------ * name: TYC 6820-00394-1 * constellation : Ophiuchus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 17 17 04.8543 DE: -26 27 48.863 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .031, .024 ) * V mag [mag]: 9.9 * B mag [mag]: 11.0 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (138) Tolosa approx. diameter [km]: 52 approx. diameter ["]: .045 distance from Earth [AU]: 1.58900 * orbital information: orbit source: Preston date of fit: 2012 Aug 25 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 1340 number of rejected observations: 113 time covered by the observations: 1905 Nov 30 - 2012 Aug 14 1 sigma uncertainty ellipse (major, minor, PA): 0.016, 0.011, 99° remarks: * orbital elements for (138) Tolosa : Mean anomaly = 341.11413094 deg Arg. of pericenter = 259.84864857 deg Long. of node = 54.90766475 deg Inclination = 3.20682942 deg Eccentricity = 0.16178222 Semimajor axis = 2.44898007 AU Perihelion dist = 2.05277865 AU Mag: H = 8.69, G = 0.15 Epoch of elements : MJD 56168.19700000 TDT (2012 Aug 29.197) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Aug 29 138 Tolosa 4h 44.2m UT 9.9 17 17 4.854-26 27 48.86TYC 6820-00394-1 11.0 12.6 52 4.3 1.589 2.772 -1.71 -149.5683 -26.463 109.19 9.21 4.7359 -0.00627 -0.19773 6.72381 -0.30992 0.00504 -0.00030 2000 339.0060802012 821.00000259.848649 54.907665 3.2068290.16178222 2.4489801 2.0527786 8.8 5.00.15 RATE 2.5717350 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.035 0.027 92 1.59 0.027 0 0 3-3 056165.0020120829_0394-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Aug 25, 22:11 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org