IOTA/IOTA-ES occultation update for (375) Ursula / TYC 7867-00225-1 event on 2008 Feb 25, 16:30 UT Visible from New Zealand, Papua New Guinea Summary ------- On 2008 Feb 25 UT, the 216 km diameter asteroid (375) Ursula will occult a 10.0 mag star in the constellation Scorpius for observers along a path across New Zealand, Papua New Guinea. In the case of an occultation, the combined light of the asteroid and the star will drop by 3.2 mag to 13.1 mag (the magnitude of the asteroid) for at most 9.7 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 Feb 25, 16:25 - 2008 Feb 25, 16:30 UT * magnitude of target star: 10.0 * magnitude drop [mag]: 3.2 * estimated maximum duration [s]: 9.7 * Moon: 80 % sunlit, 45° distance * Sun: 83° distance * rough path description: New Zealand, Papua New Guinea The occultation path -------------------- * approximate projected width [km]: 226 * 1 sigma uncertainty interval [path widths]: +/- 0.22 * 1 sigma uncertainty interval [seconds]: +/- 2.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .025 +/- .021) * 1 sigma uncertainty ellipse (major, minor, PA): ( .025", .021", 92° ) * approx speed of asteroid's shadow [km/s]: 22.3567 * website for maps: http://lunar-occultations.com/iota/asteroids/astrndx.htm http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 7867-00225-1 by 375 Ursula on 2008 Feb 25 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 126 9 6 8 0 0 16 25 41 1 129 -81 ... .. .. 127 46 20 ... .. .. 128 28 34 127 22 35 7 0 0 16 25 42 2 129 -79 125 45 8 128 58 17 125 1 40 129 39 54 128 34 14 6 0 0 16 25 42 4 129 -78 126 58 18 130 8 33 126 15 32 130 49 35 129 44 12 5 0 0 16 25 43 5 129 -77 128 9 38 131 17 16 127 27 31 131 57 47 130 52 38 4 0 0 16 25 43 7 129 -75 129 19 19 132 24 33 128 37 46 133 4 35 131 59 37 3 0 0 16 25 45 8 129 -74 130 27 26 133 30 30 129 46 26 134 10 6 133 5 18 2 0 0 16 25 46 10 129 -72 131 34 9 134 35 15 130 53 38 135 14 27 134 9 47 1 0 0 16 25 47 11 129 -71 132 39 33 135 38 52 131 59 28 136 17 43 135 13 8 0 0 0 16 25 49 13 129 -70 133 43 45 136 41 27 133 4 3 137 19 59 136 15 27 - 1 0 0 16 25 51 14 129 -68 134 46 49 137 43 5 134 7 29 138 21 20 Latitude Latitude Latitude Latitude 137 0 0 - 1 43 28 16 25 52 15 129 -67 - 3 9 55 - 0 17 58 - 3 48 17 0 19 22 138 0 0 - 2 42 43 16 25 54 17 129 -66 - 4 9 48 - 1 16 38 - 4 48 27 - 0 39 2 139 0 0 - 3 42 47 16 25 56 18 129 -64 - 5 10 29 - 2 16 6 - 5 49 24 - 1 38 15 140 0 0 - 4 43 37 16 25 59 20 129 -63 - 6 11 54 - 3 16 20 - 6 51 6 - 2 38 14 141 0 0 - 5 45 9 16 26 1 21 129 -62 - 7 14 2 - 4 17 18 - 7 53 30 - 3 38 57 142 0 0 - 6 47 22 16 26 4 22 129 -60 - 8 16 50 - 5 18 58 - 8 56 33 - 4 40 23 143 0 0 - 7 50 12 16 26 7 24 128 -59 - 9 20 13 - 6 21 15 -10 0 12 - 5 42 26 144 0 0 - 8 53 36 16 26 10 25 128 -57 -10 24 10 - 7 24 8 -11 4 23 - 6 45 6 145 0 0 - 9 57 31 16 26 13 27 128 -56 -11 28 35 - 8 27 33 -12 9 2 - 7 48 18 146 0 0 -11 1 53 16 26 17 28 128 -55 -12 33 26 - 9 31 26 -13 14 7 - 8 51 58 147 0 0 -12 6 37 16 26 21 30 127 -53 -13 38 39 -10 35 44 -14 19 32 - 9 56 5 148 0 0 -13 11 42 16 26 24 31 127 -52 -14 44 9 -11 40 23 -15 25 14 -11 0 33 149 0 0 -14 17 1 16 26 28 32 126 -50 -15 49 53 -12 45 19 -16 31 9 -12 5 18 150 0 0 -15 22 32 16 26 33 34 126 -49 -16 55 46 -13 50 28 -17 37 12 -13 10 18 151 0 0 -16 28 9 16 26 37 35 125 -47 -18 1 43 -14 55 45 -18 43 18 -14 15 27 152 0 0 -17 33 48 16 26 41 37 125 -46 -19 7 41 -16 1 7 -19 49 24 -15 20 41 153 0 0 -18 39 26 16 26 46 38 124 -45 -20 13 35 -17 6 29 -20 55 25 -16 25 57 154 0 0 -19 44 57 16 26 51 40 124 -43 -21 19 19 -18 11 47 -22 1 15 -17 31 9 155 0 0 -20 50 17 16 26 56 41 123 -42 -22 24 50 -19 16 57 -23 6 51 -18 36 14 156 0 0 -21 55 22 16 27 1 42 122 -40 -23 30 4 -20 21 53 -24 12 9 -19 41 6 157 0 0 -23 0 7 16 27 6 44 122 -39 -24 34 55 -21 26 32 -25 17 2 -20 45 43 158 0 0 -24 4 28 16 27 11 45 121 -38 -25 39 19 -22 30 49 -26 21 28 -21 49 58 159 0 0 -25 8 21 16 27 16 46 120 -36 -26 43 13 -23 34 41 -27 25 22 -22 53 50 160 0 0 -26 11 41 16 27 22 48 119 -35 -27 46 31 -24 38 3 -28 28 40 -23 57 12 161 0 0 -27 14 25 16 27 27 49 118 -34 -28 49 11 -25 40 51 -29 31 17 -25 0 1 162 0 0 -28 16 29 16 27 32 50 117 -32 -29 51 8 -26 43 1 -30 33 11 -26 2 15 163 0 0 -29 17 49 16 27 38 52 116 -31 -30 52 19 -27 44 30 -31 34 18 -27 3 48 164 0 0 -30 18 23 16 27 43 53 115 -30 -31 52 40 -28 45 15 -32 34 34 -28 4 37 165 0 0 -31 18 6 16 27 49 54 113 -28 -32 52 9 -29 45 12 -33 33 56 -29 4 40 166 0 0 -32 16 56 16 27 55 55 112 -27 -33 50 43 -30 44 18 -34 32 22 -30 3 53 167 0 0 -33 14 51 16 28 0 56 111 -26 -34 48 19 -31 42 31 -35 29 50 -31 2 13 168 0 0 -34 11 48 16 28 6 57 109 -25 -35 44 55 -32 39 48 -36 26 16 -31 59 39 169 0 0 -35 7 45 16 28 11 58 107 -23 -36 40 28 -33 36 7 -37 21 39 -32 56 7 170 0 0 -36 2 39 16 28 17 60 106 -22 -37 34 58 -34 31 26 -38 15 57 -33 51 36 171 0 0 -36 56 30 16 28 22 61 104 -21 -38 28 22 -35 25 42 -39 9 9 -34 46 4 172 0 0 -37 49 16 16 28 28 62 102 -20 -39 20 39 -36 18 56 -40 1 13 -35 39 29 173 0 0 -38 40 56 16 28 33 62 100 -19 -40 11 48 -37 11 4 -40 52 9 -36 31 50 174 0 0 -39 31 28 16 28 39 63 98 -18 -41 1 49 -38 2 7 -41 41 55 -37 23 6 175 0 0 -40 20 53 16 28 44 64 96 -17 -41 50 41 -38 52 3 -42 30 32 -38 13 16 176 0 0 -41 9 9 16 28 49 65 94 -16 -42 38 23 -39 40 53 -43 17 59 -39 2 19 177 0 0 -41 56 16 16 28 54 66 92 -15 -43 24 55 -40 28 34 -44 4 15 -39 50 16 178 0 0 -42 42 15 16 28 59 67 89 -14 -44 10 18 -41 15 8 -44 49 22 -40 37 4 179 0 0 -43 27 5 16 29 5 67 87 -13 -44 54 31 -42 0 34 -45 33 18 -41 22 45 180 0 0 -44 10 47 16 29 10 68 84 -12 -45 37 35 -42 44 52 -46 16 5 -42 7 19 -179 0 0 -44 53 21 16 29 14 69 81 -11 -46 19 31 -43 28 2 -46 57 44 -42 50 46 -178 0 0 -45 34 47 16 29 19 69 78 -10 -47 0 18 -44 10 6 -47 38 13 -43 33 5 -177 0 0 -46 15 6 16 29 24 70 76 -9 -47 39 58 -44 51 3 -48 17 36 -44 14 19 -176 0 0 -46 54 18 16 29 29 70 73 -8 -48 18 32 -45 30 54 -48 55 52 -44 54 26 -175 0 0 -47 32 26 16 29 33 71 69 -7 -48 56 0 -46 9 40 -49 33 2 -45 33 28 -174 0 0 -48 9 29 16 29 38 71 66 -6 -49 32 23 -46 47 21 -50 9 8 -46 11 26 -173 0 0 -48 45 28 16 29 42 71 63 -5 -50 7 43 -47 23 59 -50 44 10 -46 48 21 -172 0 0 -49 20 25 16 29 47 72 60 -4 -50 42 1 -47 59 34 -51 18 10 -47 24 13 -171 0 0 -49 54 21 16 29 51 72 56 -4 -51 15 17 -48 34 8 -51 51 8 -47 59 3 -170 0 0 -50 27 16 16 29 55 72 53 -3 -51 47 33 -49 7 42 -52 23 7 -48 32 53 -169 0 0 -50 59 13 16 29 59 72 50 -2 -52 18 51 -49 40 16 -52 54 7 -49 5 44 -168 0 0 -51 30 11 16 30 4 72 46 -1 -52 49 11 -50 11 51 -53 24 10 -49 37 36 -167 0 0 -52 0 13 16 30 8 72 43 -1 -53 18 34 -50 42 30 -53 53 16 -50 8 30 Uncertainty in time = +/- 2 secs [Prediction of 2008 Feb 14.0] Data for the target star ------------------------ * name: TYC 7867-00225-1 * constellation : Scorpius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 16 40 05.1346 DE: -38 06 27.145 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .020, .020 ) * V mag [mag]: 10.0 * B mag [mag]: 10.1 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (375) Ursula approx. diameter [km]: 216 approx. diameter ["]: .098 distance from Earth [AU]: 3.02800 * orbital information: orbit source: Preston date of fit: 2008 Feb 13 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): 0.015, 0.008, 96° remarks: * orbital elements for (375) Ursula : Mean anomaly = 286.05694291 deg Arg. of pericenter = 344.36071835 deg Long. of node = 336.66098524 deg Inclination = 15.93269507 deg Eccentricity = 0.10794869 Semimajor axis = 3.12403764 AU Perihelion dist = 2.78680187 AU Mag: H = 7.48, G = 0.27 Epoch of elements : MJD 54521.68800000 TDT (2008 Feb 25.688) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Feb 25 375 Ursula 16h 30.2m UT 10.0 16 40 5.135-38 6 27.15TYC 7867-00225-1 10.1 13.1 216 9.7 3.028 2.746 -17.10 -152.4584 -38.103 -64.27 -9.14 16.5040 -0.13552 -0.25985 11.16126 -5.88722 -0.00584 0.00062 2000 285.7556412008 224.00000344.360718336.660985 15.9326950.10794869 3.1240376 2.7868019 7.5 5.00.27 RATE 1.7849650 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.025 0.021 92 1.22 0.022 0 54510.5020080225_0225-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Feb 14, 02:00 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org