IOTA/IOTA-ES occultation update for (140) Siwa / TYC 6342-01234-1 event on 2009 Aug 09, 06:21 UT Visible from W USA, Canada Summary ------- On 2009 Aug 09 UT, the 110 km diameter asteroid (140) Siwa will occult a 11.2 mag star in the constellation Capricornus for observers along a path across W USA, Canada. In the case of an occultation, the combined light of the asteroid and the star will drop by 0.5 mag to 10.7 mag (the magnitude of the asteroid) for at most 16.9 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 Aug 09, 06:13 - 2009 Aug 09, 06:30 UT * midpoint of event [JD]: 2455052.7650875 * magnitude of target star: 11.2 * magnitude drop [mag]: 0.5 * estimated maximum duration [s]: 16.9 * Moon: 90 % sunlit, 47° distance * Sun: 169° distance * rough path description: W USA, Canada The occultation path -------------------- * approximate projected width [km]: 208 * 1 sigma uncertainty interval [path widths]: +/- 0.23 * 1 sigma uncertainty interval [seconds]: +/- 6.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .050 +/- .030) * 1 sigma uncertainty ellipse (major, minor, PA): ( .051", .029", 82° ) * approx speed of asteroid's shadow [km/s]: 6.4861 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6342-01234-1 by 140 Siwa on 2009 Aug 9 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 - 79 38 52 67 0 0 6 13 7 0 201 -7 - 82 18 19 ... .. .. - 83 32 34 ... .. .. - 80 39 23 66 0 0 6 13 8 1 200 -8 - 83 13 38 - 78 7 27 - 84 25 29 - 76 58 15 - 81 40 10 65 0 0 6 13 9 3 199 -9 - 84 9 45 - 79 12 55 - 85 19 26 - 78 5 52 - 82 41 21 64 0 0 6 13 11 4 198 -10 - 85 6 40 - 80 18 19 - 86 14 24 - 79 13 12 - 83 42 58 63 0 0 6 13 13 5 197 -11 - 86 4 27 - 81 23 46 - 87 10 24 - 80 20 25 - 84 45 6 62 0 0 6 13 17 6 197 -12 - 87 3 7 - 82 29 23 - 88 7 28 - 81 27 38 - 85 47 51 61 0 0 6 13 21 7 196 -13 - 88 2 43 - 83 35 16 - 89 5 37 - 82 34 58 - 86 51 16 60 0 0 6 13 25 8 195 -14 - 89 3 18 - 84 41 32 - 90 4 53 - 83 42 33 - 87 55 26 59 0 0 6 13 31 9 194 -15 - 90 4 54 - 85 48 16 - 91 5 18 - 84 50 29 - 89 0 25 58 0 0 6 13 37 10 193 -16 - 91 7 34 - 86 55 35 - 92 6 56 - 85 58 51 - 90 6 17 57 0 0 6 13 44 11 192 -17 - 92 11 24 - 88 3 32 - 93 9 49 - 87 7 47 - 91 13 8 56 0 0 6 13 51 12 191 -18 - 93 16 25 - 89 12 14 - 94 14 0 - 88 17 20 - 92 21 2 55 0 0 6 14 0 13 190 -19 - 94 22 42 - 90 21 46 - 95 19 34 - 89 27 38 - 93 30 3 54 0 0 6 14 9 15 189 -20 - 95 30 20 - 91 32 13 - 96 26 34 - 90 38 46 - 94 40 18 53 0 0 6 14 19 16 188 -21 - 96 39 24 - 92 43 42 - 97 35 6 - 91 50 50 - 95 51 51 52 0 0 6 14 31 17 187 -22 - 97 49 58 - 93 56 18 - 98 45 15 - 93 3 57 - 97 4 50 51 0 0 6 14 42 18 186 -23 - 99 2 10 - 95 10 8 - 99 57 6 - 94 18 11 - 98 19 20 50 0 0 6 14 55 19 184 -24 -100 16 5 - 96 25 18 -101 10 47 - 95 33 41 - 99 35 28 49 0 0 6 15 9 20 183 -25 -101 31 50 - 97 41 55 -102 26 24 - 96 50 33 -100 53 24 48 0 0 6 15 24 21 182 -26 -102 49 35 - 99 0 7 -103 44 7 - 98 8 55 -102 13 14 47 0 0 6 15 39 22 181 -27 -104 9 29 -100 20 3 -105 4 5 - 99 28 55 -103 35 10 46 0 0 6 15 56 23 179 -28 -105 31 41 -101 41 51 -106 26 28 -100 50 42 -104 59 21 45 0 0 6 16 13 24 178 -28 -106 56 24 -103 5 41 -107 51 29 -102 14 25 -106 26 1 44 0 0 6 16 32 25 177 -29 -108 23 51 -104 31 45 -109 19 23 -103 40 17 -107 55 24 43 0 0 6 16 52 26 175 -30 -109 54 19 -106 0 16 -110 50 27 -105 8 28 -109 27 45 42 0 0 6 17 13 27 174 -30 -111 28 5 -107 31 29 -112 24 59 -106 39 14 -111 3 24 41 0 0 6 17 36 28 172 -31 -113 5 33 -109 5 40 -114 3 24 -108 12 50 -112 42 43 40 0 0 6 17 59 28 170 -31 -114 47 7 -110 43 9 -115 46 10 -109 49 35 -114 26 10 39 0 0 6 18 24 29 168 -32 -116 33 20 -112 24 19 -117 33 51 -111 29 50 -116 14 17 38 0 0 6 18 51 30 167 -32 -118 24 52 -114 9 38 -119 27 12 -113 14 1 -118 7 44 37 0 0 6 19 19 30 165 -32 -120 22 31 -115 59 39 -121 27 8 -115 2 40 -120 7 23 36 0 0 6 19 49 31 162 -33 -122 27 24 -117 55 3 -123 34 51 -116 56 24 -122 14 19 35 0 0 6 20 21 31 160 -33 -124 40 55 -119 56 44 -125 52 0 -118 56 0 Latitude Latitude Latitude Latitude -124 0 0 34 12 54 6 20 47 32 158 -32 35 17 56 33 10 3 35 48 39 32 41 49 -125 0 0 33 47 19 6 21 3 32 157 -32 34 51 46 32 44 59 35 22 13 32 16 58 -126 0 0 33 22 33 6 21 18 32 156 -32 34 26 28 32 20 43 34 56 38 31 52 54 -127 0 0 32 58 38 6 21 33 32 155 -32 34 2 2 31 57 15 34 31 56 31 29 38 -128 0 0 32 35 32 6 21 48 32 154 -32 33 38 26 31 34 36 34 8 6 31 7 10 -129 0 0 32 13 15 6 22 3 32 153 -32 33 15 42 31 12 44 33 45 8 30 45 30 -130 0 0 31 51 48 6 22 18 32 152 -31 32 53 48 30 51 41 33 23 1 30 24 37 -131 0 0 31 31 10 6 22 33 32 151 -31 32 32 45 30 31 26 33 1 46 30 4 32 -132 0 0 31 11 21 6 22 47 32 150 -31 32 12 33 30 11 59 32 41 22 29 45 14 -133 0 0 30 52 22 6 23 2 31 149 -30 31 53 11 29 53 20 32 21 49 29 26 44 -134 0 0 30 34 11 6 23 17 31 148 -30 31 34 39 29 35 29 32 3 7 29 9 1 -135 0 0 30 16 50 6 23 31 31 147 -30 31 16 58 29 18 26 31 45 16 28 52 6 -136 0 0 30 0 17 6 23 46 31 146 -29 31 0 7 29 2 10 31 28 15 28 35 58 -137 0 0 29 44 34 6 24 0 31 145 -29 30 44 6 28 46 42 31 12 5 28 20 37 -138 0 0 29 29 39 6 24 14 30 144 -28 30 28 54 28 32 3 30 56 46 28 6 4 -139 0 0 29 15 33 6 24 28 30 143 -28 30 14 33 28 18 11 30 42 17 27 52 18 -140 0 0 29 2 16 6 24 42 30 142 -28 30 1 2 28 5 6 30 28 39 27 39 19 -141 0 0 28 49 47 6 24 55 29 141 -27 29 48 20 27 52 50 30 15 51 27 27 8 -142 0 0 28 38 7 6 25 9 29 140 -26 29 36 29 27 41 21 30 3 54 27 15 44 -143 0 0 28 27 16 6 25 22 29 140 -26 29 25 27 27 30 40 29 52 46 27 5 7 -144 0 0 28 17 14 6 25 35 28 139 -25 29 15 15 27 20 47 29 42 29 26 55 18 -145 0 0 28 8 1 6 25 48 28 138 -25 29 5 52 27 11 42 29 33 3 26 46 16 -146 0 0 27 59 36 6 26 1 27 137 -24 28 57 20 27 3 25 29 24 26 26 38 2 -147 0 0 27 52 1 6 26 14 27 136 -24 28 49 37 26 55 55 29 16 41 26 30 36 -148 0 0 27 45 14 6 26 26 26 136 -23 28 42 45 26 49 14 29 9 45 26 23 57 -149 0 0 27 39 16 6 26 38 26 135 -22 28 36 42 26 43 21 29 3 40 26 18 6 -150 0 0 27 34 8 6 26 50 25 134 -22 28 31 30 26 38 16 28 58 26 26 13 2 -151 0 0 27 29 49 6 27 1 25 133 -21 28 27 8 26 33 59 28 54 2 26 8 47 -152 0 0 27 26 19 6 27 13 24 133 -20 28 23 36 26 30 31 28 50 29 26 5 20 -153 0 0 27 23 38 6 27 24 24 132 -20 28 20 54 26 27 52 28 47 47 26 2 40 -154 0 0 27 21 47 6 27 35 23 131 -19 28 19 3 26 26 1 28 45 56 26 0 50 -155 0 0 27 20 46 6 27 45 22 130 -18 28 18 3 26 24 59 28 44 56 25 59 47 -156 0 0 27 20 35 6 27 56 22 130 -17 28 17 54 26 24 46 28 44 48 25 59 34 -157 0 0 27 21 14 6 28 6 21 129 -17 28 18 35 26 25 22 28 45 31 26 0 9 -158 0 0 27 22 43 6 28 16 20 129 -16 28 20 8 26 26 48 28 47 6 26 1 33 -159 0 0 27 25 3 6 28 25 20 128 -15 28 22 33 26 29 3 28 49 33 26 3 46 -160 0 0 27 28 13 6 28 34 19 127 -14 28 25 49 26 32 8 28 52 52 26 6 49 -161 0 0 27 32 15 6 28 43 18 127 -13 28 29 58 26 36 3 28 57 4 26 10 41 -162 0 0 27 37 7 6 28 52 17 126 -13 28 34 58 26 40 48 29 2 8 26 15 23 -163 0 0 27 42 51 6 29 0 17 126 -12 28 40 51 26 46 24 29 8 6 26 20 55 -164 0 0 27 49 27 6 29 8 16 125 -11 28 47 37 26 52 51 29 14 57 26 27 18 -165 0 0 27 56 55 6 29 15 15 124 -10 28 55 16 27 0 8 29 22 41 26 34 31 -166 0 0 28 5 15 6 29 22 14 124 -9 29 3 49 27 8 17 29 31 20 26 42 35 -167 0 0 28 14 28 6 29 29 14 123 -9 29 13 15 27 17 18 29 40 53 26 51 30 -168 0 0 28 24 34 6 29 36 13 123 -8 29 23 36 27 27 11 29 51 20 27 1 17 -169 0 0 28 35 34 6 29 42 12 122 -7 29 34 51 27 37 56 30 2 43 27 11 55 -170 0 0 28 47 27 6 29 47 11 122 -6 29 47 1 27 49 33 30 15 2 27 23 26 -171 0 0 29 0 14 6 29 53 10 121 -5 30 0 6 28 2 3 30 28 16 27 35 49 -172 0 0 29 13 56 6 29 58 9 121 -4 30 14 8 28 15 27 30 42 27 27 49 5 -173 0 0 29 28 32 6 30 2 9 120 -3 30 29 5 28 29 45 30 57 35 28 3 15 -174 0 0 29 44 4 6 30 6 8 120 -2 30 44 59 28 44 56 31 13 40 28 18 17 -175 0 0 30 0 32 6 30 10 7 119 -1 31 1 50 29 1 2 31 30 42 28 34 14 -176 0 0 30 17 56 6 30 13 6 119 -1 31 19 39 29 18 3 31 48 44 28 51 5 Uncertainty in time = +/- 6 secs [Prediction of 2008 Apr 28.0] Data for the target star ------------------------ * name: TYC 6342-01234-1 * constellation : Capricornus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 20 34 35.5479 DE: -21 11 07.269 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .025, .025 ) * V mag [mag]: 11.2 * B mag [mag]: 12.0 * Apparent position with proper motion RA(deg): 308.7979664361 DE(deg): -21.1504909601 * Equation of equinoxes (radians) : 0.000071114688844 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (140) Siwa approx. diameter [km]: 110 approx. diameter ["]: .133 distance from Earth [AU]: 1.13800 * orbital information: orbit source: Preston date of fit: 2008 Mar 20 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1225 number of rejected observations: 178 time covered by the observations: 1900 Apr 26 - 2008 Mar 10 1 sigma uncertainty ellipse (major, minor, PA): 0.044, 0.015, 79° remarks: * orbital elements for (140) Siwa : Mean anomaly = 3.97907117 deg Arg. of pericenter = 197.25125465 deg Long. of node = 107.29450399 deg Inclination = 3.18728094 deg Eccentricity = 0.21730031 Semimajor axis = 2.73306173 AU Perihelion dist = 2.13916657 AU Mag: H = 8.47, G = 0.15 Epoch of elements : MJD 55052.26500000 TDT (2009 Aug 09.265) ------ occelmnt file for Occult BEGIN ----------------------------------- 2009 Aug 9 140 Siwa 6h 21.7m UT 11.2 20 34 35.548-21 11 7.27TYC 6342-01234-1 12.1 10.7 110 16.9 1.138 -1.861 -11.06 -104.6675 -21.181 85.95 15.80 6.3621 -0.33181 0.78032 -3.36940 -1.43168 0.00090 0.00045 2000 3.4849902009 8 7.00000197.251255107.294504 3.1872810.21730031 2.7330617 2.1391666 8.3 5.00.15 RATE 2.1813730 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.051 0.029 82 1.23 0.031 0 54584.5020090809_1234-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Apr 28, 02:30 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org