IOTA/IOTA-ES occultation update for (54) Alexandra / TYC 6684-00067-1 event on 2009 May 05, 11:53 UT Visible from Summary ------- On 2009 May 05 UT, the 160 km diameter asteroid (54) Alexandra will occult a 12.0 mag star in the constellation Hydra for observers along a path across . In the case of an occultation, the combined light of the asteroid and the star will drop by 0.6 mag to 11.6 mag (the magnitude of the asteroid) for at most 17.1 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: 99 * date and approx. time of event: 2009 May 05, 11:46 - 2009 May 05, 12:01 UT * magnitude of target star: 12.0 * magnitude drop [mag]: 0.6 * estimated maximum duration [s]: 17.1 * Moon: 86 % sunlit, 23° distance * Sun: 149° distance * rough path description: The occultation path -------------------- * approximate projected width [km]: 238 * 1 sigma uncertainty interval [path widths]: +/- 0.21 * 1 sigma uncertainty interval [seconds]: +/- 4.3 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .036 +/- .027) * 1 sigma uncertainty ellipse (major, minor, PA): ( .037", .027", 101° ) * approx speed of asteroid's shadow [km/s]: 9.3687 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6684-00067-1 by 54 Alexandra on 2009 May 5 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 127 20 38 64 0 0 12 1 28 1 162 -1 129 58 19 124 44 33 131 5 6 123 39 22 128 6 6 63 0 0 12 1 28 2 163 -2 130 38 56 125 34 51 131 43 40 124 31 43 128 51 24 62 0 0 12 1 27 3 164 -2 131 19 46 126 24 36 132 22 37 125 23 20 129 36 35 61 0 0 12 1 26 4 164 -3 132 0 50 127 13 53 133 1 58 126 14 21 130 21 43 60 0 0 12 1 24 5 165 -4 132 42 12 128 2 48 133 41 43 127 4 51 131 6 52 59 0 0 12 1 23 6 166 -5 133 23 51 128 51 26 134 21 55 127 54 58 131 52 5 58 0 0 12 1 21 7 166 -6 134 5 50 129 39 53 135 2 32 128 44 46 132 37 25 57 0 0 12 1 18 8 167 -7 134 48 11 130 28 12 135 43 38 129 34 21 133 22 55 56 0 0 12 1 15 9 168 -8 135 30 55 131 16 28 136 25 12 130 23 46 134 8 37 55 0 0 12 1 12 10 168 -9 136 14 4 132 4 44 137 7 16 131 13 7 134 54 35 54 0 0 12 1 8 11 169 -10 136 57 39 132 53 3 137 49 52 132 2 26 135 40 49 53 0 0 12 1 4 13 170 -11 137 41 42 133 41 30 138 32 59 132 51 48 136 27 23 52 0 0 12 1 0 14 170 -12 138 26 15 134 30 6 139 16 41 133 41 15 137 14 19 51 0 0 12 0 55 15 171 -14 139 11 18 135 18 54 140 0 58 134 30 51 138 1 39 50 0 0 12 0 50 16 172 -15 139 56 55 136 7 58 140 45 51 135 20 39 138 49 26 49 0 0 12 0 45 17 172 -16 140 43 6 136 57 21 141 31 22 136 10 42 139 37 41 48 0 0 12 0 39 18 173 -17 141 29 54 137 47 4 142 17 34 137 1 3 140 26 27 47 0 0 12 0 32 19 174 -18 142 17 21 138 37 11 143 4 27 137 51 44 141 15 46 46 0 0 12 0 26 20 174 -19 143 5 27 139 27 44 143 52 3 138 42 48 142 5 41 45 0 0 12 0 19 21 175 -20 143 54 16 140 18 46 144 40 25 139 34 19 142 56 14 44 0 0 12 0 11 22 176 -21 144 43 50 141 10 19 145 29 35 140 26 18 143 47 27 43 0 0 12 0 3 23 177 -22 145 34 11 142 2 26 146 19 34 141 18 48 144 39 23 42 0 0 11 59 55 24 178 -24 146 25 21 142 55 10 147 10 25 142 11 53 145 32 5 41 0 0 11 59 46 25 178 -25 147 17 23 143 48 34 148 2 11 143 5 35 146 25 35 40 0 0 11 59 37 26 179 -26 148 10 20 144 42 41 148 54 55 143 59 57 147 19 57 39 0 0 11 59 28 27 180 -27 149 4 14 145 37 33 149 48 38 144 55 3 148 15 14 38 0 0 11 59 18 28 181 -28 149 59 9 146 33 13 150 43 26 145 50 54 149 11 29 37 0 0 11 59 8 29 182 -30 150 55 9 147 29 46 151 39 20 146 47 36 150 8 45 36 0 0 11 58 57 30 183 -31 151 52 17 148 27 15 152 36 25 147 45 11 151 7 7 35 0 0 11 58 46 31 184 -32 152 50 36 149 25 43 153 34 45 148 43 42 152 6 38 34 0 0 11 58 34 32 185 -33 153 50 12 150 25 14 154 34 24 149 43 15 153 7 24 33 0 0 11 58 22 33 186 -35 154 51 9 151 25 53 155 35 28 150 43 52 154 9 28 32 0 0 11 58 9 34 187 -36 155 53 32 152 27 44 156 38 1 151 45 39 155 12 57 31 0 0 11 57 56 35 188 -37 156 57 28 153 30 53 157 42 9 152 48 41 156 17 56 30 0 0 11 57 43 35 190 -39 158 3 1 154 35 24 158 48 0 153 53 2 157 24 32 29 0 0 11 57 29 36 191 -40 159 10 21 155 41 24 159 55 39 154 58 49 158 32 51 28 0 0 11 57 14 37 192 -41 160 19 33 156 48 59 161 5 17 156 6 8 159 43 3 27 0 0 11 56 59 38 194 -43 161 30 48 157 58 17 162 17 2 157 15 5 160 55 15 26 0 0 11 56 43 39 195 -44 162 44 15 159 9 25 163 31 4 158 25 49 162 9 37 25 0 0 11 56 27 39 197 -45 164 0 5 160 22 32 164 47 36 159 38 29 163 26 22 24 0 0 11 56 11 40 198 -47 165 18 33 161 37 50 166 6 52 160 53 13 164 45 43 23 0 0 11 55 53 40 200 -48 166 39 53 162 55 28 167 29 8 162 10 13 166 7 54 22 0 0 11 55 35 41 202 -49 168 4 23 164 15 42 168 54 43 163 29 42 167 33 14 21 0 0 11 55 17 41 204 -51 169 32 23 165 38 44 170 24 0 164 51 53 169 2 4 20 0 0 11 54 58 42 206 -52 171 4 20 167 4 55 171 57 26 166 17 4 170 34 48 19 0 0 11 54 37 42 208 -53 172 40 45 168 34 34 173 35 36 167 45 34 172 11 57 18 0 0 11 54 17 42 210 -55 174 22 14 170 8 7 175 19 11 169 17 47 173 54 10 17 0 0 11 53 55 42 212 -56 176 9 37 171 46 4 177 9 5 170 54 10 175 42 13 16 0 0 11 53 32 42 214 -57 178 3 55 173 29 3 179 6 29 172 35 17 177 37 8 15 0 0 11 53 8 42 216 -59 -179 53 27 175 17 51 -178 47 0 174 21 52 179 40 17 14 0 0 11 52 43 42 219 -60 -177 40 34 177 13 29 -176 29 6 176 14 50 Latitude Latitude Latitude Latitude 180 0 0 13 50 48 11 52 39 42 219 -60 15 3 5 12 40 19 15 34 2 12 11 13 -179 0 0 13 23 30 11 52 27 41 220 -60 14 35 15 12 13 31 15 5 57 11 44 37 -178 0 0 12 57 14 11 52 15 41 221 -61 14 8 27 11 47 44 14 38 55 11 19 1 -177 0 0 12 31 59 11 52 3 41 222 -61 13 42 42 11 22 56 14 12 57 10 54 25 -176 0 0 12 7 45 11 51 52 40 223 -61 13 18 0 10 59 9 13 48 3 10 30 48 -175 0 0 11 44 31 11 51 40 40 224 -62 12 54 20 10 36 20 13 24 11 10 8 9 -174 0 0 11 22 18 11 51 29 40 225 -62 12 31 42 10 14 30 13 1 21 9 46 28 -173 0 0 11 1 4 11 51 18 39 226 -62 12 10 4 9 53 39 12 39 33 9 25 46 -172 0 0 10 40 50 11 51 7 39 227 -62 11 49 27 9 33 46 12 18 46 9 6 1 -171 0 0 10 21 35 11 50 56 38 228 -62 11 29 51 9 14 50 11 59 1 8 47 14 -170 0 0 10 3 19 11 50 45 38 229 -62 11 11 15 8 56 53 11 40 16 8 29 24 -169 0 0 9 46 1 11 50 34 37 230 -62 10 53 39 8 39 52 11 22 31 8 12 30 -168 0 0 9 29 41 11 50 24 37 230 -62 10 37 2 8 23 49 11 5 46 7 56 33 -167 0 0 9 14 20 11 50 14 36 231 -62 10 21 24 8 8 42 10 50 1 7 41 33 -166 0 0 8 59 56 11 50 4 36 232 -62 10 6 45 7 54 33 10 35 16 7 27 29 -165 0 0 8 46 29 11 49 54 35 232 -62 9 53 4 7 41 19 10 21 30 7 14 20 -164 0 0 8 34 0 11 49 44 34 233 -61 9 40 23 7 29 2 10 8 42 7 2 8 -163 0 0 8 22 28 11 49 34 34 234 -61 9 28 39 7 17 41 9 56 53 6 50 51 -162 0 0 8 11 53 11 49 25 33 234 -61 9 17 54 7 7 15 9 46 3 6 40 30 -161 0 0 8 2 15 11 49 16 32 235 -60 9 8 6 6 57 46 9 36 12 6 31 4 -160 0 0 7 53 34 11 49 7 32 235 -60 8 59 17 6 49 12 9 27 19 6 22 33 -159 0 0 7 45 49 11 48 58 31 236 -59 8 51 25 6 41 34 9 19 24 6 14 58 -158 0 0 7 39 1 11 48 49 30 236 -59 8 44 31 6 34 51 9 12 27 6 8 17 -157 0 0 7 33 9 11 48 41 29 237 -58 8 38 34 6 29 5 9 6 29 6 2 32 -156 0 0 7 28 14 11 48 33 29 237 -58 8 33 36 6 24 13 9 1 28 5 57 43 -155 0 0 7 24 16 11 48 25 28 238 -57 8 29 35 6 20 18 8 57 26 5 53 48 -154 0 0 7 21 15 11 48 17 27 238 -57 8 26 32 6 17 18 8 54 22 5 50 49 -153 0 0 7 19 10 11 48 9 26 239 -56 8 24 26 6 15 14 8 52 17 5 48 45 -152 0 0 7 18 2 11 48 2 25 239 -55 8 23 19 6 14 5 8 51 9 5 47 36 -151 0 0 7 17 51 11 47 54 25 239 -54 8 23 9 6 13 53 8 51 1 5 47 23 -150 0 0 7 18 37 11 47 47 24 240 -54 8 23 58 6 14 36 8 51 51 5 48 6 -149 0 0 7 20 21 11 47 41 23 240 -53 8 25 46 6 16 16 8 53 40 5 49 44 -148 0 0 7 23 2 11 47 34 22 240 -52 8 28 32 6 18 53 8 56 28 5 52 19 -147 0 0 7 26 40 11 47 28 21 241 -51 8 32 16 6 22 26 9 0 15 5 55 50 -146 0 0 7 31 17 11 47 22 20 241 -51 8 37 0 6 26 56 9 5 3 6 0 17 -145 0 0 7 36 52 11 47 16 19 241 -50 8 42 44 6 32 23 9 10 50 6 5 41 -144 0 0 7 43 26 11 47 10 19 241 -49 8 49 27 6 38 48 9 17 37 6 12 3 -143 0 0 7 50 59 11 47 5 18 242 -48 8 57 11 6 46 11 9 25 25 6 19 21 -142 0 0 7 59 31 11 47 0 17 242 -47 9 5 55 6 54 32 9 34 15 6 27 38 -141 0 0 8 9 3 11 46 55 16 242 -46 9 15 40 7 3 52 9 44 5 6 36 53 -140 0 0 8 19 35 11 46 50 15 242 -45 9 26 26 7 14 10 9 54 58 6 47 6 -139 0 0 8 31 8 11 46 46 14 243 -45 9 38 15 7 25 28 10 6 54 6 58 18 -138 0 0 8 43 42 11 46 42 13 243 -44 9 51 6 7 37 47 10 19 52 7 10 30 -137 0 0 8 57 18 11 46 38 12 243 -43 10 5 0 7 51 5 10 33 54 7 23 42 -136 0 0 9 11 56 11 46 35 11 243 -42 10 19 58 8 5 25 10 49 1 7 37 54 -135 0 0 9 27 37 11 46 31 10 243 -41 10 36 0 8 20 46 11 5 12 7 53 8 -134 0 0 9 44 21 11 46 28 9 244 -40 10 53 7 8 37 10 11 22 29 8 9 23 -133 0 0 10 2 10 11 46 26 8 244 -39 11 11 19 8 54 36 11 40 53 8 26 40 -132 0 0 10 21 4 11 46 23 7 244 -38 11 30 39 9 13 6 12 0 23 8 45 0 -131 0 0 10 41 3 11 46 21 6 244 -37 11 51 5 9 32 39 12 21 2 9 4 24 -130 0 0 11 2 8 11 46 19 5 244 -36 12 12 39 9 53 18 12 42 49 9 24 52 -129 0 0 11 24 21 11 46 18 4 245 -35 12 35 23 10 15 2 13 5 46 9 46 25 -128 0 0 11 47 41 11 46 17 3 245 -34 12 59 16 10 37 53 13 29 53 10 9 3 -127 0 0 12 12 11 11 46 16 2 245 -33 13 24 19 11 1 51 13 55 12 10 32 48 -126 0 0 12 37 50 11 46 16 1 245 -32 13 50 35 11 26 56 .. .. .. .. .. .. Uncertainty in time = +/- 5 secs [Prediction of 2008 Mar 20.0] Data for the target star ------------------------ * name: TYC 6684-00067-1 * constellation : Hydra * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 12 41 54.4806 DE: -23 57 40.988 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .030, .024 ) * V mag [mag]: 12.0 * B mag [mag]: 13.0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (54) Alexandra approx. diameter [km]: 160 approx. diameter ["]: .131 distance from Earth [AU]: 1.68700 * orbital information: orbit source: Preston date of fit: 2008 Mar 20 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 792 number of rejected observations: 82 time covered by the observations: 1909 Jan 24 - 2008 Feb 17 1 sigma uncertainty ellipse (major, minor, PA): 0.022, 0.013, 122° remarks: * orbital elements for (54) Alexandra : Mean anomaly = 292.63026395 deg Arg. of pericenter = 345.76374401 deg Long. of node = 313.43671768 deg Inclination = 11.80706748 deg Eccentricity = 0.19683925 Semimajor axis = 2.71103839 AU Perihelion dist = 2.17739962 AU Mag: H = 7.74, G = 0.15 Epoch of elements : MJD 54956.49500000 TDT (2009 May 05.495) ------ occelmnt file for Occult BEGIN ----------------------------------- 2009 May 5 54 Alexandra 11h 53.9m UT 12.0 12 41 54.481-23 57 40.99TYC 6684-00067-1 13.0 11.6 160 17.1 1.687 -1.673 15.28 148.5154 -23.965 0.70 16.37 11.8982 0.40984 0.61637 -4.40182 2.93024 0.00285 0.00040 2000 291.1961632009 429.00000345.763744313.436718 11.8070670.19683925 2.7110384 2.1773996 7.7 5.00.15 RATE 2.2080080 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.037 0.027 101 1.21 0.028 0 54545.5020090505_0067-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 20, 07:53 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org