IOTA/IOTA-ES occultation update for (636) Erika / TYC 7394-01127-1 event on 2008 Oct 16, 11:10 UT Visible from Australia Summary ------- On 2008 Oct 16 UT, the 74 km diameter asteroid (636) Erika will occult a 12.2 mag star in the constellation Sagittarius for observers along a path across Australia. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.5 mag to 14.6 mag (the magnitude of the asteroid) for at most 2.8 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: 71 * date and approx. time of event: 2008 Oct 16, 11:11 - 2008 Oct 16, 11:14 UT * midpoint of event [JD]: 2454755.96564583 * magnitude of target star: 12.2 * magnitude drop [mag]: 2.5 * estimated maximum duration [s]: 2.8 * Moon: 96 % sunlit, 128° distance * Sun: 75° distance * rough path description: Australia The occultation path -------------------- * approximate projected width [km]: 75 * 1 sigma uncertainty interval [path widths]: +/- 0.82 * 1 sigma uncertainty interval [seconds]: +/- 2.1 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .036 +/- .033) * 1 sigma uncertainty ellipse (major, minor, PA): ( .036", .033", 90° ) * approx speed of asteroid's shadow [km/s]: 26.7101 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 7394-01127-1 by 636 Erika on 2008 Oct 16 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 105 0 0 -34 27 39 11 11 33 73 277 0 -34 48 59 -34 6 20 -35 24 0 -33 31 24 106 0 0 -34 10 24 11 11 36 73 275 -1 -34 31 48 -33 49 2 -35 6 56 -33 14 0 107 0 0 -33 52 39 11 11 40 72 273 -2 -34 14 7 -33 31 13 -34 49 21 -32 56 5 108 0 0 -33 34 24 11 11 43 71 272 -3 -33 55 55 -33 12 53 -34 31 15 -32 37 39 109 0 0 -33 15 37 11 11 47 70 270 -4 -33 37 12 -32 54 3 -34 12 39 -32 18 43 110 0 0 -32 56 19 11 11 51 69 269 -5 -33 17 58 -32 34 41 -33 53 31 -31 59 14 111 0 0 -32 36 30 11 11 54 68 267 -6 -32 58 13 -32 14 48 -33 33 53 -31 39 15 112 0 0 -32 16 10 11 11 58 68 266 -6 -32 37 57 -31 54 24 -33 13 43 -31 18 44 113 0 0 -31 55 19 11 12 1 67 265 -7 -32 17 10 -31 33 29 -32 53 2 -30 57 42 114 0 0 -31 33 56 11 12 5 66 264 -8 -31 55 51 -31 12 2 -32 31 51 -30 36 9 115 0 0 -31 12 2 11 12 8 65 263 -9 -31 34 1 -30 50 4 -32 10 7 -30 14 4 116 0 0 -30 49 36 11 12 12 64 262 -10 -31 11 40 -30 27 34 -31 47 53 -29 51 27 117 0 0 -30 26 39 11 12 16 63 261 -11 -30 48 47 -30 4 33 -31 25 7 -29 28 20 118 0 0 -30 3 11 11 12 19 62 260 -12 -30 25 23 -29 41 0 -31 1 50 -29 4 40 119 0 0 -29 39 12 11 12 23 61 259 -13 -30 1 28 -29 16 57 -30 38 1 -28 40 30 120 0 0 -29 14 41 11 12 26 60 258 -14 -29 37 1 -28 52 22 -30 13 42 -28 15 48 121 0 0 -28 49 39 11 12 30 59 257 -15 -29 12 3 -28 27 15 -29 48 51 -27 50 35 122 0 0 -28 24 6 11 12 34 58 256 -16 -28 46 34 -28 1 38 -29 23 29 -27 24 50 123 0 0 -27 58 2 11 12 37 57 255 -17 -28 20 34 -27 35 30 -28 57 36 -26 58 35 124 0 0 -27 31 27 11 12 41 56 255 -18 -27 54 4 -27 8 51 -28 31 12 -26 31 50 125 0 0 -27 4 21 11 12 44 55 254 -19 -27 27 3 -26 41 41 -28 4 18 -26 4 33 126 0 0 -26 36 46 11 12 48 54 253 -20 -26 59 31 -26 14 2 -27 36 53 -25 36 47 127 0 0 -26 8 40 11 12 51 53 252 -21 -26 31 29 -25 45 52 -27 8 58 -25 8 30 128 0 0 -25 40 4 11 12 55 52 252 -22 -26 2 58 -25 17 12 -26 40 33 -24 39 44 129 0 0 -25 10 59 11 12 58 51 251 -23 -25 33 57 -24 48 3 -26 11 39 -24 10 29 130 0 0 -24 41 25 11 13 1 50 251 -24 -25 4 27 -24 18 25 -25 42 15 -23 40 44 131 0 0 -24 11 22 11 13 5 49 250 -25 -24 34 28 -23 48 18 -25 12 23 -23 10 31 132 0 0 -23 40 51 11 13 8 48 249 -26 -24 4 0 -23 17 43 -24 42 2 -22 39 50 133 0 0 -23 9 52 11 13 11 47 249 -27 -23 33 5 -22 46 41 -24 11 13 -22 8 41 134 0 0 -22 38 26 11 13 15 46 248 -28 -23 1 43 -22 15 11 -23 39 56 -21 37 5 135 0 0 -22 6 33 11 13 18 45 248 -29 -22 29 53 -21 43 14 -23 8 12 -21 5 3 136 0 0 -21 34 14 11 13 21 44 247 -30 -21 57 37 -21 10 52 -22 36 2 -20 32 35 137 0 0 -21 1 29 11 13 24 43 247 -32 -21 24 56 -20 38 4 -22 3 27 -19 59 42 138 0 0 -20 28 20 11 13 27 42 246 -33 -20 51 50 -20 4 51 -21 30 26 -19 26 24 139 0 0 -19 54 46 11 13 30 41 246 -34 -20 18 20 -19 31 15 -20 57 0 -18 52 42 140 0 0 -19 20 49 11 13 33 40 245 -35 -19 44 26 -18 57 15 -20 23 11 -18 18 37 141 0 0 -18 46 30 11 13 36 39 245 -36 -19 10 9 -18 22 52 -19 48 59 -17 44 10 142 0 0 -18 11 49 11 13 39 37 245 -37 -18 35 30 -17 48 8 -19 14 25 -17 9 22 143 0 0 -17 36 47 11 13 42 36 244 -38 -18 0 31 -17 13 4 -18 39 30 -16 34 13 144 0 0 -17 1 25 11 13 45 35 244 -39 -17 25 11 -16 37 39 -18 4 15 -15 58 45 145 0 0 -16 25 44 11 13 48 34 243 -40 -16 49 33 -16 1 56 -17 28 40 -15 22 58 146 0 0 -15 49 45 11 13 50 33 243 -42 -16 13 36 -15 25 55 -16 52 46 -14 46 54 147 0 0 -15 13 29 11 13 53 32 243 -43 -15 37 22 -14 49 37 -16 16 35 -14 10 33 148 0 0 -14 36 57 11 13 55 31 242 -44 -15 0 52 -14 13 4 -15 40 8 -13 33 56 149 0 0 -14 0 10 11 13 58 29 242 -45 -14 24 7 -13 36 15 -15 3 26 -12 57 5 150 0 0 -13 23 10 11 14 0 28 242 -46 -13 47 8 -12 59 14 -14 26 29 -12 20 1 151 0 0 -12 45 57 11 14 2 27 242 -47 -13 9 56 -12 22 0 -13 49 20 -11 42 45 152 0 0 -12 8 33 11 14 5 26 241 -49 -12 32 33 -11 44 34 -13 11 58 -11 5 18 153 0 0 -11 30 59 11 14 7 25 241 -50 -11 54 59 -11 6 59 -12 34 26 -10 27 42 154 0 0 -10 53 15 11 14 9 24 241 -51 -11 17 17 -10 29 15 -11 56 45 - 9 49 57 155 0 0 -10 15 24 11 14 11 22 241 -52 -10 39 26 - 9 51 24 -11 18 55 - 9 12 4 156 0 0 - 9 37 27 11 14 12 21 240 -53 -10 1 29 - 9 13 26 -10 40 59 - 8 34 6 157 0 0 - 8 59 24 11 14 14 20 240 -54 - 9 23 27 - 8 35 23 -10 2 56 - 7 56 3 158 0 0 - 8 21 18 11 14 16 19 240 -56 - 8 45 20 - 7 57 17 - 9 24 50 - 7 17 57 159 0 0 - 7 43 9 11 14 17 18 240 -57 - 8 7 11 - 7 19 8 - 8 46 40 - 6 39 49 160 0 0 - 7 4 58 11 14 19 17 240 -58 - 7 29 0 - 6 40 58 - 8 8 28 - 6 1 39 161 0 0 - 6 26 48 11 14 20 15 240 -59 - 6 50 49 - 6 2 48 - 7 30 16 - 5 23 31 162 0 0 - 5 48 39 11 14 22 14 240 -60 - 6 12 39 - 5 24 40 - 6 52 5 - 4 45 24 163 0 0 - 5 10 32 11 14 23 13 239 -61 - 5 34 32 - 4 46 34 - 6 13 56 - 4 7 20 164 0 0 - 4 32 29 11 14 24 12 239 -63 - 4 56 28 - 4 8 33 - 5 35 50 - 3 29 20 165 0 0 - 3 54 32 11 14 25 11 239 -64 - 4 18 29 - 3 30 36 - 4 57 49 - 2 51 26 166 0 0 - 3 16 40 11 14 26 10 239 -65 - 3 40 36 - 2 52 47 - 4 19 53 - 2 13 38 167 0 0 - 2 38 57 11 14 26 8 239 -66 - 3 2 50 - 2 15 5 - 3 42 5 - 1 35 59 168 0 0 - 2 1 22 11 14 27 7 239 -67 - 2 25 13 - 1 37 31 - 3 4 25 - 0 58 29 169 0 0 - 1 23 57 11 14 28 6 239 -69 - 1 47 47 - 1 0 9 - 2 26 55 - 0 21 9 170 0 0 - 0 46 43 11 14 28 5 239 -70 - 1 10 31 - 0 22 57 - 1 49 35 0 15 59 171 0 0 - 0 9 42 11 14 28 4 239 -71 - 0 33 27 0 14 2 - 1 12 28 0 52 54 172 0 0 0 27 6 11 14 29 2 239 -72 0 3 24 0 50 48 - 0 35 33 1 29 36 173 0 0 1 3 40 11 14 29 1 239 -73 0 40 0 1 27 19 0 1 7 2 6 2 174 0 0 1 39 58 11 14 29 0 239 -74 1 16 20 .. .. .. 0 37 32 .. .. .. Uncertainty in time = +/- 2 secs [Prediction of 2008 Sep 11.0] Data for the target star ------------------------ * name: TYC 7394-01127-1 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 35 49.0539 DE: -30 53 19.646 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .029, .030 ) * V mag [mag]: 12.2 * B mag [mag]: 12.2 * Apparent position with proper motion RA(deg): 279.0976630575 DE(deg): -30.8836506669 * Equation of equinoxes (radians) : 0.000046889113791 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (636) Erika approx. diameter [km]: 74 approx. diameter ["]: .040 distance from Earth [AU]: 2.52300 * orbital information: orbit source: Preston date of fit: 2008 Sep 05 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 896 number of rejected observations: 54 time covered by the observations: 1907 Mar 03 - 2008 Aug 21 1 sigma uncertainty ellipse (major, minor, PA): 0.022, 0.012, 90° remarks: * orbital elements for (636) Erika : Mean anomaly = 338.07229023 deg Arg. of pericenter = 297.57801222 deg Long. of node = 34.73841772 deg Inclination = 7.92649511 deg Eccentricity = 0.17512980 Semimajor axis = 2.91026772 AU Perihelion dist = 2.40059311 AU Mag: H = 9.54, G = 0.15 Epoch of elements : MJD 54755.46600000 TDT (2008 Oct 16.466) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Oct 16 636 Erika 11h 10.5m UT 12.2 18 35 49.054-30 53 19.65TYC 7394-01127-1 12.2 14.6 74 2.8 2.523 4.030 8.37 85.9784 -30.891 8.74 -9.11 11.1755 0.01901 -0.12316 14.88369 2.39983 0.00542 0.00014 2000 336.98717920081011.00000297.578012 34.738418 7.9264950.17512980 2.9102677 2.4005931 9.5 5.00.15 RATE 1.9852010 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.036 0.033 90 1.82 0.033 0 54720.5020081016_1127-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Sep 11, 20:21 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org