IOTA/IOTA-ES occultation update for (375) Ursula / TYC 7877-00031-1 event on 2008 Apr 03, 14:15 UT Visible from W Australia Summary ------- On 2008 Apr 03 UT, the 216 km diameter asteroid (375) Ursula will occult a 10.9 mag star in the constellation Scorpius for observers along a path across W Australia. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.0 mag to 12.7 mag (the magnitude of the asteroid) for at most 23.0 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: 99 * date and approx. time of event: 2008 Apr 03, 14:12 - 2008 Apr 03, 14:18 UT * midpoint of event [JD]: 2454560.0941625 * magnitude of target star: 10.9 * magnitude drop [mag]: 2.0 * estimated maximum duration [s]: 23.0 * Moon: 9 % sunlit, 80° distance * Sun: 113° distance * rough path description: W Australia The occultation path -------------------- * approximate projected width [km]: 820 * 1 sigma uncertainty interval [path widths]: +/- 0.28 * 1 sigma uncertainty interval [seconds]: +/- 5.6 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .035 +/- .030) * 1 sigma uncertainty ellipse (major, minor, PA): ( .035", .030", 90° ) * approx speed of asteroid's shadow [km/s]: 9.4060 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 7877-00031-1 by 375 Ursula on 2008 Apr 3 Centre Star Star Sun Path Limit1 Path Limit2 Error Limit1 Error Limit2 E. Longitude Latitude U.T. Alt Az Alt o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' " Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude 114 42 4 -12 30 37 14 12 41 3 133 -57 120 45 45 -17 28 47 ... .. .. .. .. .. 122 50 48 -19 0 59 ... .. .. .. .. .. 115 37 12 -13 58 12 14 12 47 5 133 -57 120 54 51 -18 13 16 ... .. .. .. .. .. 122 55 31 -19 41 15 ... .. .. .. .. .. 116 11 28 -15 6 29 14 12 52 6 132 -58 121 1 48 -18 55 52 ... .. .. .. .. .. 122 58 45 -20 20 18 ... .. .. .. .. .. 116 35 40 -16 5 29 14 12 57 7 132 -58 121 6 52 -19 36 51 ... .. .. .. .. .. 123 0 39 -20 58 15 ... .. .. .. .. .. 116 53 29 -16 58 41 14 13 3 8 132 -58 121 10 15 -20 16 25 ... .. .. .. .. .. 123 1 18 -21 35 12 ... .. .. .. .. .. 117 6 45 -17 47 47 14 13 8 8 132 -58 121 12 8 -20 54 44 ... .. .. .. .. .. 123 0 48 -22 11 13 ... .. .. .. .. .. 117 16 30 -18 33 44 14 13 14 9 132 -58 121 12 37 -21 31 55 ... .. .. .. .. .. 122 59 14 -22 46 23 ... .. .. .. .. .. 117 23 24 -19 17 11 14 13 19 10 132 -58 121 11 51 -22 8 5 ... .. .. .. .. .. 122 56 37 -23 20 46 ... .. .. .. .. .. 117 27 54 -19 58 34 14 13 25 10 132 -58 121 9 53 -22 43 18 ... .. .. .. .. .. 122 53 3 -23 54 25 ... .. .. .. .. .. 117 30 21 -20 38 10 14 13 30 11 131 -57 121 6 48 -23 17 39 111 0 48 -15 11 59 122 48 32 -24 27 22 ... .. .. .. .. .. 117 30 58 -21 16 14 14 13 36 11 131 -57 121 2 40 -23 51 11 111 45 36 -16 31 39 122 43 8 -24 59 40 ... .. .. .. .. .. 117 29 58 -21 52 57 14 13 41 12 131 -57 120 57 32 -24 23 58 112 10 52 -17 33 6 122 36 52 -25 31 21 ... .. .. .. .. .. 117 27 28 -22 28 27 14 13 47 12 131 -57 120 51 26 -24 56 2 112 26 53 -18 26 3 122 29 46 -26 2 26 ... .. .. .. .. .. 117 23 36 -23 2 51 14 13 52 12 131 -56 120 44 24 -25 27 26 112 37 4 -19 13 40 122 21 51 -26 32 58 ... .. .. .. .. .. 117 18 27 -23 36 14 14 13 57 13 131 -56 120 36 29 -25 58 11 112 43 1 -19 57 30 122 13 8 -27 2 56 ... .. .. .. .. .. 117 12 6 -24 8 40 14 14 3 13 131 -56 120 27 42 -26 28 20 112 45 42 -20 38 25 122 3 38 -27 32 24 ... .. .. .. .. .. 117 4 36 -24 40 15 14 14 8 13 131 -55 120 18 3 -26 57 53 112 45 41 -21 16 59 121 53 22 -28 1 21 107 46 36 -16 54 34 116 56 2 -25 11 0 14 14 14 13 131 -55 120 7 35 -27 26 52 112 43 23 -21 53 35 121 42 21 -28 29 48 108 28 48 -18 13 18 116 46 25 -25 40 58 14 14 19 14 131 -55 119 56 19 -27 55 18 112 39 4 -22 28 29 121 30 36 -28 57 47 108 47 30 -19 9 56 116 35 47 -26 10 12 14 14 25 14 131 -54 119 44 14 -28 23 12 112 32 58 -23 1 52 121 18 6 -29 25 17 108 56 42 -19 57 46 116 24 11 -26 38 44 14 14 30 14 131 -54 119 31 21 -28 50 35 112 25 14 -23 33 56 121 4 52 -29 52 21 109 0 7 -20 40 17 116 11 38 -27 6 34 14 14 36 14 131 -54 119 17 42 -29 17 28 112 15 59 -24 4 45 120 50 54 -30 18 57 108 59 24 -21 19 4 115 58 8 -27 33 45 14 14 41 14 131 -53 119 3 16 -29 43 51 112 5 19 -24 34 26 120 36 13 -30 45 7 108 55 25 -21 54 59 115 43 44 -28 0 18 14 14 47 15 131 -53 118 48 4 -30 9 44 111 53 19 -25 3 4 120 20 49 -31 10 50 108 48 46 -22 28 32 115 28 26 -28 26 13 14 14 52 15 131 -52 118 32 6 -30 35 9 111 40 2 -25 30 42 120 4 41 -31 36 8 108 39 48 -23 0 5 115 12 14 -28 51 31 14 14 57 15 131 -52 118 15 22 -31 0 5 111 25 31 -25 57 22 119 47 49 -32 1 0 108 28 46 -23 29 52 114 55 10 -29 16 13 14 15 3 15 131 -52 117 57 52 -31 24 32 111 9 49 -26 23 7 119 30 14 -32 25 26 108 15 52 -23 58 4 114 37 12 -29 40 19 14 15 8 15 131 -51 117 39 35 -31 48 31 110 52 58 -26 47 59 119 11 56 -32 49 27 108 1 13 -24 24 48 114 18 22 -30 3 49 14 15 14 15 131 -51 117 20 33 -32 12 2 110 34 58 -27 11 59 118 52 53 -33 13 2 107 44 55 -24 50 9 113 58 40 -30 26 44 14 15 19 15 131 -50 117 0 44 -32 35 4 110 15 51 -27 35 8 118 33 6 -33 36 11 107 27 2 -25 14 12 113 38 5 -30 49 4 14 15 25 15 131 -50 116 40 9 -32 57 39 109 55 37 -27 57 26 118 12 35 -33 58 55 107 7 37 -25 36 58 113 16 37 -31 10 49 14 15 30 15 131 -49 116 18 47 -33 19 45 109 34 17 -28 18 53 117 51 19 -34 21 14 106 46 42 -25 58 30 112 54 16 -31 31 57 14 15 36 15 131 -49 115 56 38 -33 41 22 109 11 50 -28 39 30 117 29 18 -34 43 6 106 24 18 -26 18 48 112 31 2 -31 52 30 14 15 41 15 131 -49 115 33 41 -34 2 30 108 48 17 -28 59 16 117 6 30 -35 4 31 106 0 24 -26 37 51 112 6 55 -32 12 27 14 15 47 15 131 -48 115 9 56 -34 23 9 108 23 36 -29 18 11 116 42 57 -35 25 30 105 35 0 -26 55 39 111 41 53 -32 31 46 14 15 52 15 131 -48 114 45 22 -34 43 18 107 57 48 -29 36 13 116 18 37 -35 46 2 105 8 4 -27 12 8 111 15 56 -32 50 28 14 15 57 15 131 -47 114 19 59 -35 2 57 107 30 51 -29 53 22 115 53 30 -36 6 7 104 39 33 -27 27 17 110 49 4 -33 8 31 14 16 3 15 131 -47 113 53 46 -35 22 5 107 2 43 -30 9 35 115 27 35 -36 25 44 104 9 24 -27 40 59 110 21 15 -33 25 55 14 16 8 15 131 -46 113 26 43 -35 40 41 106 33 23 -30 24 50 115 0 51 -36 44 52 103 37 30 -27 53 11 109 52 28 -33 42 39 14 16 14 15 131 -46 112 58 48 -35 58 46 106 2 49 -30 39 6 114 33 17 -37 3 31 103 3 45 -28 3 43 109 22 43 -33 58 41 14 16 19 15 132 -45 112 30 1 -36 16 17 105 30 58 -30 52 19 114 4 54 -37 21 39 102 27 59 -28 12 24 108 51 58 -34 13 59 14 16 25 14 132 -45 112 0 22 -36 33 14 104 57 48 -31 4 25 113 35 40 -37 39 18 101 49 59 -28 19 2 108 20 12 -34 28 33 14 16 30 14 132 -44 111 29 48 -36 49 37 104 23 13 -31 15 21 113 5 34 -37 56 24 101 9 27 -28 23 16 107 47 24 -34 42 21 14 16 36 14 132 -44 110 58 19 -37 5 23 103 47 11 -31 25 0 112 34 36 -38 12 59 100 25 56 -28 24 37 107 13 31 -34 55 19 14 16 41 14 132 -43 110 25 55 -37 20 32 103 9 35 -31 33 17 112 2 44 -38 28 59 99 38 43 -28 22 22 106 38 32 -35 7 27 14 16 47 14 132 -43 109 52 33 -37 35 2 102 30 19 -31 40 4 111 29 58 -38 44 25 98 46 39 -28 15 16 106 2 24 -35 18 40 14 16 52 13 133 -42 109 18 13 -37 48 52 101 49 14 -31 45 10 110 56 16 -38 59 15 97 47 24 -28 0 53 105 25 6 -35 28 57 14 16 57 13 133 -42 108 42 54 -38 2 0 101 6 9 -31 48 24 110 21 37 -39 13 28 96 34 42 -27 32 46 104 46 34 -35 38 14 14 17 3 13 133 -41 108 6 33 -38 14 24 100 20 49 -31 49 29 109 46 1 -39 27 3 ... .. .. .. .. .. 104 6 45 -35 46 26 14 17 8 13 133 -41 107 29 10 -38 26 2 99 32 55 -31 48 2 109 9 25 -39 39 56 ... .. .. .. .. .. 103 25 36 -35 53 29 14 17 14 12 134 -40 106 50 42 -38 36 52 98 41 57 -31 43 33 108 31 50 -39 52 8 ... .. .. .. .. .. 102 43 2 -35 59 17 14 17 19 12 134 -40 106 11 9 -38 46 51 97 47 14 -31 35 14 107 53 12 -40 3 36 ... .. .. .. .. .. 101 58 58 -36 3 44 14 17 25 12 134 -39 105 30 27 -38 55 57 96 47 35 -31 21 48 107 13 31 -40 14 17 ... .. .. .. .. .. 101 13 17 -36 6 43 14 17 30 11 135 -39 104 48 34 -39 4 6 95 40 46 -31 0 53 106 32 45 -40 24 10 ... .. .. .. .. .. 100 25 53 -36 8 2 14 17 36 11 135 -38 104 5 28 -39 11 15 94 21 33 -30 26 50 105 50 52 -40 33 11 ... .. .. .. .. .. 99 36 35 -36 7 31 14 17 41 10 135 -37 103 21 6 -39 17 19 92 24 9 -29 12 24 105 7 50 -40 41 18 ... .. .. .. .. .. 98 45 11 -36 4 56 14 17 47 10 136 -37 102 35 25 -39 22 14 ... .. .. .. .. .. 104 23 38 -40 48 28 ... .. .. .. .. .. 97 51 26 -35 59 55 14 17 52 9 136 -36 101 48 20 -39 25 54 ... .. .. .. .. .. 103 38 11 -40 54 37 ... .. .. .. .. .. 96 54 57 -35 52 4 14 17 57 9 137 -36 100 59 48 -39 28 14 ... .. .. .. .. .. 102 51 29 -40 59 40 ... .. .. .. .. .. 95 55 14 -35 40 45 14 18 3 8 137 -35 100 9 42 -39 29 4 ... .. .. .. .. .. 102 3 27 -41 3 33 ... .. .. .. .. .. 94 51 29 -35 25 6 14 18 8 7 138 -34 99 17 57 -39 28 18 ... .. .. .. .. .. 101 14 2 -41 6 11 ... .. .. .. .. .. 93 42 26 -35 3 37 14 18 14 6 138 -34 98 24 24 -39 25 43 ... .. .. .. .. .. 100 23 9 -41 7 26 ... .. .. .. .. .. 92 25 43 -34 33 37 14 18 19 5 139 -33 97 28 53 -39 21 6 ... .. .. .. .. .. 99 30 45 -41 7 13 ... .. .. .. .. .. 90 55 47 -33 48 55 14 18 25 4 140 -32 96 31 11 -39 14 11 ... .. .. .. .. .. 98 36 41 -41 5 21 ... .. .. .. .. .. 88 48 42 -32 23 1 14 18 30 2 141 -30 95 31 1 -39 4 35 ... .. .. .. .. .. 97 40 52 -41 1 40 ... .. .. .. .. .. Uncertainty in time = +/- 7 secs [Prediction of 2008 Mar 7.0] Data for the target star ------------------------ * name: TYC 7877-00031-1 * constellation : Scorpius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 17 08 43.4096 DE: -42 21 30.289 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .029, .029 ) * V mag [mag]: 10.9 * B mag [mag]: 12.5 * Apparent position with proper motion RA(deg): 257.3335406762 DE(deg): -42.3694635170 * Equation of equinoxes (radians) : 0.000040846751092 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (375) Ursula approx. diameter [km]: 216 approx. diameter ["]: .119 distance from Earth [AU]: 2.49700 * orbital information: orbit source: Preston date of fit: 2008 Feb 03 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 650 number of rejected observations: 82 time covered by the observations: 1904 Sep 19 - 2007 Aug 07 1 sigma uncertainty ellipse (major, minor, PA): 0.019, 0.010, 90° remarks: * orbital elements for (375) Ursula : Mean anomaly = 292.87500111 deg Arg. of pericenter = 344.31341768 deg Long. of node = 336.65725080 deg Inclination = 15.93254816 deg Eccentricity = 0.10798352 Semimajor axis = 3.12436809 AU Perihelion dist = 2.78698781 AU Mag: H = 7.48, G = 0.27 Epoch of elements : MJD 54559.59400000 TDT (2008 Apr 03.594) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Apr 3 375 Ursula 14h 15.6m UT 10.9 17 8 43.410-42 21 30.29TYC 7877-00031-1 12.5 12.7 216 23.0 2.497 0.814 -16.37 -149.0002 -42.354 -33.11 5.60 14.2599 -0.84430 -0.46663 2.56608 -4.64765 -0.00524 0.00128 2000 291.1627772008 325.00000344.313418336.657251 15.9325480.10798352 3.1243681 2.7869878 7.5 5.00.27 RATE 1.7846820 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.035 0.030 90 1.28 0.033 0 54532.5020080403_0031-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 07, 13:40 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org