IOTA/IOTA-ES occultation update for (494) Virtus / TYC 7361-00039-1 event on 2009 Jul 06, 12:19 UT Visible from Summary ------- On 2009 Jul 06 UT, the 86 km diameter asteroid (494) Virtus will occult a 9.6 mag star in the constellation Scorpius for observers along a path across . In the case of an occultation, the combined light of the asteroid and the star will drop by 3.6 mag to 13.2 mag (the magnitude of the asteroid) for at most 10.0 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: 97 * date and approx. time of event: 2009 Jul 06, 12:11 - 2009 Jul 06, 12:27 UT * magnitude of target star: 9.6 * magnitude drop [mag]: 3.6 * estimated maximum duration [s]: 10.0 * Moon: 99 % sunlit, 17° distance * Sun: 154° distance * rough path description: The occultation path -------------------- * approximate projected width [km]: 135 * 1 sigma uncertainty interval [path widths]: +/- 0.39 * 1 sigma uncertainty interval [seconds]: +/- 4.5 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .033 +/- .025) * 1 sigma uncertainty ellipse (major, minor, PA): ( .033", .025", 97° ) * approx speed of asteroid's shadow [km/s]: 8.5398 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 7361-00039-1 by 494 Virtus on 2009 Jul 6 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 103 51 38 37 0 0 12 27 14 11 144 -1 105 5 48 102 38 44 106 4 36 101 42 41 105 23 28 36 0 0 12 27 7 13 145 -2 106 38 26 104 9 52 107 37 55 103 13 21 106 57 49 35 0 0 12 27 0 14 146 -4 108 13 45 105 43 21 109 14 5 104 46 14 108 34 58 34 0 0 12 26 51 16 147 -6 109 52 4 107 19 27 110 53 25 106 21 35 110 15 16 33 0 0 12 26 41 17 148 -7 111 33 48 108 58 29 112 36 22 107 59 43 111 59 7 32 0 0 12 26 30 19 149 -9 113 19 21 110 40 49 114 23 23 109 40 57 113 47 0 31 0 0 12 26 18 21 150 -11 115 9 16 112 26 52 116 15 4 111 25 44 115 39 30 30 0 0 12 26 4 22 152 -13 117 4 12 114 17 11 118 12 7 113 14 30 117 37 18 29 0 0 12 25 48 24 153 -15 119 4 58 116 12 23 120 15 27 115 7 51 119 41 19 28 0 0 12 25 31 26 154 -17 121 12 35 118 13 13 122 26 15 117 6 29 Latitude Latitude Latitude Latitude 120 0 0 27 51 15 12 25 28 26 155 -17 28 33 42 27 9 31 29 7 20 26 37 26 121 0 0 27 23 37 12 25 19 27 155 -18 28 5 46 26 42 11 28 39 9 26 10 20 122 0 0 26 56 46 12 25 10 27 156 -19 27 38 36 26 15 37 28 11 44 25 43 59 123 0 0 26 30 40 12 25 1 28 157 -20 27 12 13 25 49 48 27 45 7 25 18 22 124 0 0 26 5 21 12 24 52 29 158 -21 26 46 37 25 24 45 27 19 17 24 53 31 125 0 0 25 40 48 12 24 42 30 158 -22 26 21 47 25 0 27 26 54 14 24 29 24 126 0 0 25 17 0 12 24 33 30 159 -23 25 57 44 24 36 54 26 29 59 24 6 3 127 0 0 24 53 59 12 24 23 31 160 -23 25 34 28 24 14 7 26 6 30 23 43 27 128 0 0 24 31 43 12 24 13 32 161 -24 25 11 58 23 52 5 25 43 48 23 21 35 129 0 0 24 10 14 12 24 2 32 162 -25 24 50 15 23 30 49 25 21 54 23 0 28 130 0 0 23 49 30 12 23 52 33 163 -26 24 29 18 23 10 18 25 0 46 22 40 7 131 0 0 23 29 32 12 23 42 33 163 -27 24 9 7 22 50 32 24 40 26 22 20 30 132 0 0 23 10 20 12 23 31 34 164 -28 23 49 43 22 31 32 24 20 52 22 1 38 133 0 0 22 51 54 12 23 20 34 165 -29 23 31 5 22 13 16 24 2 4 21 43 31 134 0 0 22 34 13 12 23 9 35 166 -30 23 13 14 21 55 46 23 44 4 21 26 9 135 0 0 22 17 18 12 22 58 35 167 -30 22 56 8 21 39 1 23 26 50 21 9 31 136 0 0 22 1 8 12 22 47 36 168 -31 22 39 48 21 23 1 23 10 22 20 53 38 137 0 0 21 45 44 12 22 36 36 169 -32 22 24 15 21 7 45 22 54 41 20 38 29 138 0 0 21 31 5 12 22 25 37 170 -33 22 9 27 20 53 15 22 39 46 20 24 5 139 0 0 21 17 11 12 22 14 37 171 -33 21 55 25 20 39 29 22 25 37 20 10 26 140 0 0 21 4 2 12 22 2 37 172 -34 21 42 8 20 26 28 22 12 14 19 57 30 141 0 0 20 51 39 12 21 51 38 173 -35 21 29 37 20 14 12 21 59 37 19 45 19 142 0 0 20 40 1 12 21 40 38 174 -36 21 17 52 20 2 40 21 47 46 19 33 52 143 0 0 20 29 7 12 21 28 38 175 -36 21 6 52 19 51 52 21 36 41 19 23 10 144 0 0 20 18 58 12 21 16 38 176 -37 20 56 37 19 41 50 21 26 21 19 13 11 145 0 0 20 9 35 12 21 5 39 177 -38 20 47 8 19 32 31 21 16 47 19 3 57 146 0 0 20 0 55 12 20 53 39 178 -38 20 38 24 19 23 57 21 7 59 18 55 26 147 0 0 19 53 1 12 20 42 39 179 -39 20 30 25 19 16 7 20 59 57 18 47 39 148 0 0 19 45 51 12 20 30 39 180 -40 20 23 11 19 9 1 20 52 39 18 40 37 149 0 0 19 39 26 12 20 18 39 181 -40 20 16 42 19 2 40 20 46 8 18 34 18 150 0 0 19 33 46 12 20 6 39 182 -41 20 10 59 18 57 2 20 40 21 18 28 43 151 0 0 19 28 50 12 19 55 39 183 -41 20 6 0 18 52 9 20 35 20 18 23 51 152 0 0 19 24 38 12 19 43 39 184 -42 20 1 46 18 48 0 20 31 5 18 19 44 153 0 0 19 21 11 12 19 31 39 185 -42 19 58 17 18 44 34 20 27 34 18 16 20 154 0 0 19 18 29 12 19 19 39 186 -43 19 55 33 18 41 53 20 24 49 18 13 40 155 0 0 19 16 31 12 19 8 39 187 -43 19 53 34 18 39 56 20 22 49 18 11 44 156 0 0 19 15 18 12 18 56 39 188 -44 19 52 20 18 38 44 20 21 35 18 10 31 157 0 0 19 14 49 12 18 44 39 189 -44 19 51 51 18 38 15 20 21 6 18 10 3 158 0 0 19 15 4 12 18 33 39 190 -44 19 52 7 18 38 30 20 21 22 18 10 18 159 0 0 19 16 4 12 18 21 39 191 -45 19 53 8 18 39 29 20 22 23 18 11 16 160 0 0 19 17 49 12 18 10 38 192 -45 19 54 54 18 41 13 20 24 10 18 12 59 161 0 0 19 20 18 12 17 58 38 193 -45 19 57 25 18 43 40 20 26 42 18 15 26 162 0 0 19 23 32 12 17 47 38 194 -46 20 0 41 18 46 52 20 30 0 18 18 36 163 0 0 19 27 31 12 17 36 38 195 -46 20 4 42 18 50 49 20 34 3 18 22 30 164 0 0 19 32 14 12 17 24 37 196 -46 20 9 28 18 55 29 20 38 52 18 27 9 165 0 0 19 37 42 12 17 13 37 197 -46 20 15 0 19 0 54 20 44 26 18 32 31 166 0 0 19 43 55 12 17 2 37 198 -46 20 21 17 19 7 3 20 50 46 18 38 38 167 0 0 19 50 53 12 16 51 36 199 -47 20 28 19 19 13 57 20 57 52 18 45 29 168 0 0 19 58 36 12 16 40 36 200 -47 20 36 7 19 21 36 21 5 44 18 53 4 169 0 0 20 7 5 12 16 29 35 201 -47 20 44 40 19 29 59 21 14 22 19 1 23 170 0 0 20 16 18 12 16 18 35 202 -47 20 54 0 19 39 7 21 23 46 19 10 27 171 0 0 20 26 17 12 16 8 34 203 -47 21 4 5 19 49 0 21 33 56 19 20 15 172 0 0 20 37 1 12 15 57 34 204 -47 21 14 56 19 59 38 21 44 52 19 30 48 173 0 0 20 48 31 12 15 47 33 204 -46 21 26 33 20 11 1 21 56 35 19 42 6 174 0 0 21 0 47 12 15 37 33 205 -46 21 38 56 20 23 9 22 9 4 19 54 9 175 0 0 21 13 48 12 15 26 32 206 -46 21 52 5 20 36 3 22 22 20 20 6 57 176 0 0 21 27 35 12 15 16 32 207 -46 22 6 1 20 49 41 22 36 23 20 20 29 177 0 0 21 42 8 12 15 7 31 208 -46 22 20 44 21 4 6 22 51 13 20 34 47 178 0 0 21 57 28 12 14 57 30 208 -46 22 36 13 21 19 16 23 6 50 20 49 50 179 0 0 22 13 33 12 14 47 30 209 -45 22 52 28 21 35 12 23 23 14 21 5 39 180 0 0 22 30 25 12 14 38 29 210 -45 23 9 31 21 51 54 23 40 26 21 22 13 -179 0 0 22 48 4 12 14 29 28 211 -45 23 27 21 22 9 21 23 58 25 21 39 32 -178 0 0 23 6 29 12 14 20 28 211 -44 23 45 58 22 27 35 24 17 11 21 57 37 -177 0 0 23 25 41 12 14 11 27 212 -44 24 5 22 22 46 35 24 36 46 22 16 28 -176 0 0 23 45 40 12 14 2 26 213 -43 24 25 34 23 6 21 24 57 8 22 36 5 -175 0 0 24 6 25 12 13 54 25 213 -43 24 46 33 23 26 54 25 18 18 22 56 28 -174 0 0 24 27 58 12 13 46 25 214 -42 25 8 20 23 48 13 25 40 17 23 17 37 -173 0 0 24 50 18 12 13 38 24 214 -42 25 30 55 24 10 19 26 3 3 23 39 32 -172 0 0 25 13 25 12 13 30 23 215 -41 25 54 17 24 33 11 26 26 38 24 2 14 -171 0 0 25 37 19 12 13 22 22 216 -41 26 18 28 24 56 50 26 51 2 24 25 41 -170 0 0 26 2 1 12 13 15 21 216 -40 26 43 26 25 21 16 27 16 14 24 49 55 -169 0 0 26 27 30 12 13 8 20 217 -39 27 9 12 25 46 28 27 42 14 25 14 55 -168 0 0 26 53 46 12 13 1 20 218 -39 27 35 47 26 12 27 28 9 4 25 40 41 -167 0 0 27 20 50 12 12 55 19 218 -38 28 3 9 26 39 13 28 36 41 26 7 14 -166 0 0 27 48 41 12 12 49 18 219 -37 28 31 20 27 6 46 29 5 8 26 34 33 -165 0 0 28 17 19 12 12 43 17 219 -37 29 0 18 27 35 5 29 34 23 27 2 38 -164 0 0 28 46 45 12 12 37 16 220 -36 29 30 5 28 4 11 30 4 26 27 31 29 -163 0 0 29 16 58 12 12 31 15 220 -35 30 0 39 28 34 3 30 35 18 28 1 6 -162 0 0 29 47 57 12 12 26 14 221 -34 30 32 1 29 4 42 31 6 59 28 31 29 -161 0 0 30 19 44 12 12 22 13 222 -33 31 4 11 29 36 6 31 39 27 29 2 37 -160 0 0 30 52 17 12 12 17 12 222 -33 31 37 7 30 8 17 32 12 44 29 34 31 -159 0 0 31 25 36 12 12 13 11 223 -32 32 10 51 30 41 13 32 46 48 30 7 10 -158 0 0 31 59 41 12 12 9 10 223 -31 32 45 22 31 14 54 33 21 40 30 40 33 -157 0 0 32 34 32 12 12 6 9 224 -30 33 20 39 31 49 21 33 57 18 31 14 41 -156 0 0 33 10 9 12 12 3 8 224 -29 33 56 43 32 24 31 34 33 44 31 49 33 -155 0 0 33 46 30 12 12 0 7 225 -28 34 33 32 33 0 26 35 10 56 32 25 8 -154 0 0 34 23 35 12 11 58 6 225 -27 35 11 5 33 37 4 35 48 53 33 1 27 -153 0 0 35 1 24 12 11 56 5 226 -26 35 49 24 34 14 25 36 27 36 33 38 27 -152 0 0 35 39 55 12 11 54 4 227 -25 36 28 26 34 52 29 37 7 3 34 16 9 -151 0 0 36 19 9 12 11 53 3 227 -24 37 8 10 35 31 13 37 47 14 34 54 32 -150 0 0 36 59 4 12 11 52 2 228 -23 37 48 37 36 10 38 38 28 7 .. .. .. -149 0 0 37 39 39 12 11 51 1 228 -22 38 29 46 36 50 43 .. .. .. .. .. .. Uncertainty in time = +/- 5 secs [Prediction of 2008 Apr 25.0] Data for the target star ------------------------ * name: TYC 7361-00039-1 * constellation : Scorpius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 17 10 22.2613 DE: -31 08 54.302 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .021, .021 ) * V mag [mag]: 9.6 * B mag [mag]: 10.7 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (494) Virtus approx. diameter [km]: 86 approx. diameter ["]: .063 distance from Earth [AU]: 1.87300 * orbital information: orbit source: Preston date of fit: 2008 Apr 25 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1137 number of rejected observations: 110 time covered by the observations: 1902 Oct 07 - 2008 Feb 13 1 sigma uncertainty ellipse (major, minor, PA): 0.026, 0.013, 101° remarks: * orbital elements for (494) Virtus : Mean anomaly = 10.98820169 deg Arg. of pericenter = 217.66188926 deg Long. of node = 38.37018288 deg Inclination = 7.07559902 deg Eccentricity = 0.05712347 Semimajor axis = 2.98743349 AU Perihelion dist = 2.81678092 AU Mag: H = 9.07, G = 0.15 Epoch of elements : MJD 55018.51400000 TDT (2009 Jul 06.514) ------ occelmnt file for Occult BEGIN ----------------------------------- 2009 Jul 6 494 Virtus 12h 19.7m UT 9.6 17 10 22.261-31 8 54.30TYC 7361-00039-1 10.7 13.2 86 10.0 1.873 -1.756 1.79 148.0401 -31.148 -3.73 22.64 12.3290 0.06039 0.76990 -4.80512 0.38004 0.00240 0.00051 2000 9.3630642009 628.00000217.661889 38.370183 7.0755990.05712347 2.9874335 2.8167809 9.0 5.00.15 RATE 1.9087830 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.033 0.025 97 1.39 0.025 0 54581.5020090706_0039-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Apr 25, 07:25 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org