IOTA/IOTA-ES occultation update for (2804) Yrjo / TYC 4967-00904-1 event on 2009 Aug 05, 12:38 UT Visible from Summary ------- On 2009 Aug 05 UT, the 23 km diameter asteroid (2804) Yrjo will occult a 10.5 mag star in the constellation Virgo for observers along a path across . In the case of an occultation, the combined light of the asteroid and the star will drop by 6.9 mag to 17.4 mag (the magnitude of the asteroid) for at most 0.9 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: 15 * date and approx. time of event: 2009 Aug 05, 12:38 - 2009 Aug 05, 12:40 UT * magnitude of target star: 10.5 * magnitude drop [mag]: 6.9 * estimated maximum duration [s]: 0.9 * Moon: 100 % sunlit, 102° distance * Sun: 73° distance * rough path description: Additional comments ------------------- 1.3" double star The occultation path -------------------- * approximate projected width [km]: 46 * 1 sigma uncertainty interval [path widths]: +/- 4.61 * 1 sigma uncertainty interval [seconds]: +/- 5.6 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .066 +/- .048) * 1 sigma uncertainty ellipse (major, minor, PA): ( .068", .045", 110° ) * approx speed of asteroid's shadow [km/s]: 26.1213 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 4967-00904-1 by 2804 Yrjo on 2009 Aug 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 102 45 52 49 0 0 12 38 1 30 227 0 102 22 59 103 8 52 98 57 49 106 47 56 103 50 6 48 0 0 12 38 6 30 228 -1 103 27 18 104 13 2 100 2 58 107 51 44 104 56 14 47 0 0 12 38 11 30 230 -3 104 33 28 105 19 9 101 9 38 108 57 55 106 4 25 46 0 0 12 38 17 30 232 -4 105 41 38 106 27 21 102 17 54 110 6 39 107 14 47 45 0 0 12 38 22 30 233 -5 106 51 56 107 37 48 103 27 55 111 18 8 108 27 31 44 0 0 12 38 28 30 235 -6 108 4 33 108 50 38 104 39 50 112 32 36 109 42 48 43 0 0 12 38 34 30 236 -8 109 19 40 110 6 7 105 53 48 113 50 18 111 0 53 42 0 0 12 38 39 29 238 -9 110 37 31 111 24 26 107 10 0 115 11 34 112 22 3 41 0 0 12 38 45 29 240 -10 111 58 23 112 45 56 108 28 40 116 36 48 113 46 38 40 0 0 12 38 51 29 241 -12 113 22 35 114 10 55 109 50 2 118 6 30 115 15 2 39 0 0 12 38 58 28 243 -13 114 50 30 115 39 49 111 14 23 119 41 18 116 47 45 38 0 0 12 39 4 27 245 -15 116 22 38 117 13 9 112 42 6 121 21 58 118 25 24 37 0 0 12 39 10 27 247 -17 117 59 33 118 51 34 114 13 33 123 9 33 120 8 46 36 0 0 12 39 17 26 248 -18 119 41 59 120 35 53 115 49 16 125 5 28 121 58 50 35 0 0 12 39 23 25 250 -20 121 30 56 122 27 10 117 29 52 127 11 42 123 57 1 34 0 0 12 39 30 23 252 -22 123 27 39 124 26 52 119 16 9 129 31 14 126 5 11 33 0 0 12 39 37 22 254 -24 125 33 56 126 37 4 121 9 8 132 8 52 Latitude Latitude Latitude Latitude 127 0 0 32 35 56 12 39 39 21 254 -25 32 21 59 32 49 59 30 18 9 35 5 20 128 0 0 32 10 40 12 39 42 21 255 -26 31 56 51 32 24 35 29 54 8 34 38 29 129 0 0 31 46 31 12 39 45 20 256 -27 31 32 50 32 0 19 29 31 9 34 12 52 130 0 0 31 23 29 12 39 48 19 257 -28 31 9 55 31 37 10 29 9 14 33 48 27 131 0 0 31 1 34 12 39 50 18 257 -28 30 48 7 31 15 7 28 48 20 33 25 13 132 0 0 30 40 44 12 39 53 18 258 -29 30 27 23 30 54 11 28 28 29 33 3 9 133 0 0 30 21 0 12 39 55 17 259 -30 30 7 45 30 34 21 28 9 40 32 42 16 134 0 0 30 2 20 12 39 57 16 259 -31 29 49 11 30 15 36 27 51 53 32 22 33 135 0 0 29 44 46 12 39 59 15 260 -32 29 31 41 29 57 55 27 35 6 32 3 58 136 0 0 29 28 15 12 40 1 14 261 -32 29 15 15 29 41 20 27 19 21 31 46 32 137 0 0 29 12 48 12 40 3 14 261 -33 28 59 53 29 25 48 27 4 36 31 30 13 138 0 0 28 58 25 12 40 5 13 262 -34 28 45 34 29 11 21 26 50 51 31 15 2 139 0 0 28 45 4 12 40 7 12 262 -35 28 32 17 28 57 56 26 38 7 31 0 57 140 0 0 28 32 47 12 40 8 11 263 -35 28 20 3 28 45 35 26 26 22 30 47 59 141 0 0 28 21 31 12 40 10 10 263 -36 28 8 51 28 34 17 26 15 37 30 36 7 142 0 0 28 11 18 12 40 11 9 264 -37 27 58 41 28 24 1 26 5 52 30 25 20 143 0 0 28 2 7 12 40 12 8 264 -37 27 49 32 28 14 47 .. .. .. 30 15 39 144 0 0 27 53 58 12 40 13 8 265 -38 27 41 25 28 6 35 .. .. .. 30 7 2 145 0 0 27 46 50 12 40 14 7 265 -39 27 34 19 27 59 25 .. .. .. 29 59 31 146 0 0 27 40 43 12 40 15 6 266 -39 27 28 14 27 53 16 .. .. .. 29 53 3 147 0 0 27 35 37 12 40 16 5 266 -40 27 23 10 27 48 8 .. .. .. 29 47 40 148 0 0 27 31 31 12 40 16 4 267 -40 27 19 6 27 44 2 .. .. .. 29 43 20 149 0 0 27 28 27 12 40 17 3 267 -41 27 16 2 27 40 56 .. .. .. 29 40 5 150 0 0 27 26 23 12 40 17 2 268 -41 27 13 59 27 38 52 .. .. .. 29 37 52 151 0 0 27 25 19 12 40 17 1 268 -42 27 12 56 27 37 48 .. .. .. 29 36 43 152 0 0 27 25 16 12 40 17 0 269 -42 27 12 53 27 37 44 .. .. .. 29 36 38 Uncertainty in time = +/- 6 secs [Prediction of 2008 Apr 25.0] Data for the target star ------------------------ * name: TYC 4967-00904-1 * constellation : Virgo * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 13 48 30.3350 DE: -00 51 30.994 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .027, .019 ) * V mag [mag]: 10.5 * B mag [mag]: 10.9 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (2804) Yrjo approx. diameter [km]: 23 approx. diameter ["]: .010 distance from Earth [AU]: 3.02300 * orbital information: orbit source: Preston date of fit: 2008 Apr 25 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 712 number of rejected observations: 19 time covered by the observations: 1941 Apr 03 - 2008 Mar 03 1 sigma uncertainty ellipse (major, minor, PA): 0.063, 0.041, 114° remarks: * orbital elements for (2804) Yrjo : Mean anomaly = 309.66476193 deg Arg. of pericenter = 172.36813351 deg Long. of node = 109.50423285 deg Inclination = 11.20386530 deg Eccentricity = 0.07074048 Semimajor axis = 3.01486480 AU Perihelion dist = 2.80159183 AU Mag: H = 11.15, G = 0.15 Epoch of elements : MJD 55048.52700000 TDT (2009 Aug 05.527) ------ occelmnt file for Occult BEGIN ----------------------------------- 2009 Aug 5 2804 Yrjo 12h 38.2m UT 10.5 13 48 30.335- 0 51 30.99TYC 4967-00904-1 10.9 17.4 23 0.9 3.023 2.412 -23.04 63.3670 -0.852 -8.06 16.85 12.6373 0.46302 0.72882 12.43415 -7.92244 0.00506 -0.00164 2000 308.0593052009 728.00000172.368134109.504233 11.2038650.07074048 3.0148648 2.801591811.7 5.00.15 RATE 1.8827920 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.068 0.045 110 5.61 0.048 0 54581.5020090805_0904-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Apr 25, 07:50 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org