IOTA/IOTA-ES occultation update for (1922) Zulu / HIP 98517 event on 2008 May 02, 19:36 UT Visible from SE Australia Summary ------- On 2008 May 02 UT, the 12 km diameter asteroid (1922) Zulu will occult a 7.2 mag star in the constellation Aquila for observers along a path across SE Australia. In the case of an occultation, the combined light of the asteroid and the star will drop by 8.1 mag to 15.3 mag (the magnitude of the asteroid) for at most 0.5 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: . The event at a glimpse ---------------------- * Rank: 16 * date and approx. time of event: 2008 May 02, 19:32 - 2008 May 02, 19:35 UT * midpoint of event [JD]: 2454589.31692917 * magnitude of target star: 7.2 * magnitude drop [mag]: 8.1 * estimated maximum duration [s]: 0.5 * Moon: 10 % sunlit, 63° distance * Sun: 96° distance * rough path description: SE Australia The occultation path -------------------- * approximate projected width [km]: 13 * 1 sigma uncertainty interval [path widths]: +/- 4.24 * 1 sigma uncertainty interval [seconds]: +/- 1.6 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .063 +/- .032) * 1 sigma uncertainty ellipse (major, minor, PA): ( .064", .031", 85° ) * approx speed of asteroid's shadow [km/s]: 26.0127 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 98517 by 1922 Zulu on 2008 May 2 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 123 1 6 -75 0 0 19 32 39 1 22 -23 123 15 48 122 46 23 125 19 46 120 40 50 124 32 10 -74 0 0 19 32 39 2 21 -23 124 45 52 124 18 27 126 41 34 122 21 32 125 53 56 -73 0 0 19 32 39 3 20 -24 126 6 47 125 41 5 127 55 18 123 51 35 127 8 3 -72 0 0 19 32 39 4 18 -24 127 20 9 126 55 57 129 2 24 125 12 54 128 15 48 -71 0 0 19 32 40 5 17 -24 128 27 14 128 4 21 130 3 58 126 26 59 129 18 11 -70 0 0 19 32 40 6 16 -24 129 29 2 129 7 19 131 0 51 127 34 59 130 16 0 -69 0 0 19 32 41 7 16 -24 130 26 20 130 5 40 131 53 46 128 37 50 131 9 56 -68 0 0 19 32 41 8 15 -24 131 19 47 131 0 4 132 43 16 129 36 15 132 0 29 -67 0 0 19 32 42 9 14 -24 132 9 55 131 51 3 133 29 49 130 30 53 132 48 7 -66 0 0 19 32 43 10 13 -24 132 57 10 132 39 4 134 13 49 131 22 12 133 33 11 -65 0 0 19 32 44 11 12 -24 133 41 53 133 24 29 134 55 34 132 10 38 134 16 1 -64 0 0 19 32 45 12 12 -24 134 24 24 134 7 39 135 35 22 132 56 32 134 56 52 -63 0 0 19 32 46 13 11 -23 135 4 57 134 48 47 136 13 26 133 40 12 135 35 58 -62 0 0 19 32 47 14 11 -23 135 43 46 135 28 9 136 49 57 134 21 54 136 13 30 -61 0 0 19 32 48 15 10 -23 136 21 3 136 5 57 137 25 7 135 1 49 136 49 39 -60 0 0 19 32 49 16 9 -23 136 56 58 136 42 19 137 59 3 135 40 11 137 24 32 -59 0 0 19 32 51 17 9 -23 137 31 39 137 17 26 138 31 55 136 17 9 137 58 19 -58 0 0 19 32 52 18 8 -23 138 5 14 137 51 25 139 3 47 136 52 50 138 31 6 -57 0 0 19 32 54 19 8 -23 138 37 49 138 24 23 139 34 48 137 27 24 139 2 58 -56 0 0 19 32 55 20 7 -22 139 9 31 138 56 26 140 5 1 138 0 56 139 34 2 -55 0 0 19 32 57 22 7 -22 139 40 25 139 27 39 140 34 31 138 33 33 140 4 21 -54 0 0 19 32 59 23 6 -22 140 10 35 139 58 8 141 3 23 139 5 20 140 34 1 -53 0 0 19 33 1 24 6 -22 140 40 5 140 27 56 141 31 41 139 36 22 141 3 4 -52 0 0 19 33 3 25 5 -21 141 9 1 140 57 7 141 59 28 140 6 42 141 31 35 -51 0 0 19 33 5 26 5 -21 141 37 24 141 25 46 142 26 47 140 36 26 141 59 36 -50 0 0 19 33 7 27 4 -21 142 5 18 141 53 54 142 53 40 141 5 36 142 27 11 -49 0 0 19 33 9 28 4 -21 142 32 47 142 21 36 143 20 11 141 34 15 142 54 22 -48 0 0 19 33 12 29 3 -20 142 59 51 142 48 54 143 46 22 142 2 27 143 21 12 -47 0 0 19 33 14 30 3 -20 143 26 35 143 15 49 144 12 15 142 30 13 143 47 43 -46 0 0 19 33 16 31 2 -20 143 53 0 143 42 25 144 37 51 142 57 38 144 13 56 -45 0 0 19 33 19 32 2 -19 144 19 8 144 8 44 145 3 14 143 24 42 144 39 54 -44 0 0 19 33 22 33 1 -19 144 45 1 144 34 47 145 28 24 143 51 28 145 5 39 -43 0 0 19 33 24 34 1 -18 145 10 40 145 0 37 145 53 23 144 17 58 145 31 11 -42 0 0 19 33 27 35 0 -18 145 36 9 145 26 14 146 18 13 144 44 14 145 56 34 -41 0 0 19 33 30 36 360 -18 146 1 27 145 51 41 146 42 55 145 10 18 146 21 48 -40 0 0 19 33 33 37 359 -17 146 26 37 146 16 59 147 7 31 145 36 10 146 46 54 -39 0 0 19 33 36 38 359 -17 146 51 40 146 42 9 147 32 1 146 1 53 147 11 55 -38 0 0 19 33 39 39 358 -16 147 16 37 147 7 13 147 56 27 146 27 28 147 36 51 -37 0 0 19 33 42 40 358 -16 147 41 29 147 32 13 148 20 50 146 52 57 148 1 43 -36 0 0 19 33 45 41 357 -15 148 6 18 147 57 8 148 45 12 147 18 20 148 26 33 -35 0 0 19 33 48 42 357 -15 148 31 5 148 22 1 149 9 33 147 43 39 148 51 22 -34 0 0 19 33 51 43 356 -14 148 55 51 148 46 53 149 33 55 148 8 55 149 16 11 -33 0 0 19 33 55 44 355 -14 149 20 37 149 11 45 149 58 18 148 34 10 149 41 1 -32 0 0 19 33 58 45 355 -13 149 45 24 149 36 37 150 22 43 148 59 24 150 5 52 -31 0 0 19 34 2 46 354 -13 150 10 14 150 1 31 150 47 12 149 24 39 150 30 47 -30 0 0 19 34 5 46 353 -12 150 35 6 150 26 28 151 11 46 149 49 55 150 55 46 -29 0 0 19 34 9 47 352 -12 151 0 3 150 51 29 151 36 24 150 15 14 151 20 50 -28 0 0 19 34 13 48 352 -11 151 25 5 151 16 35 152 1 9 150 40 37 151 46 0 -27 0 0 19 34 16 49 351 -10 151 50 13 151 41 47 152 26 2 151 6 5 152 11 16 -26 0 0 19 34 20 50 350 -10 152 15 28 152 7 5 152 51 2 151 31 38 152 36 41 -25 0 0 19 34 24 51 349 -9 152 40 51 152 32 32 153 16 11 151 57 18 153 2 15 -24 0 0 19 34 28 52 348 -9 153 6 23 152 58 7 153 41 31 152 23 6 153 27 58 -23 0 0 19 34 32 53 347 -8 153 32 5 153 23 52 154 7 2 152 49 2 153 53 53 -22 0 0 19 34 36 54 346 -7 153 57 58 153 49 47 154 32 44 153 15 8 154 19 59 -21 0 0 19 34 40 55 345 -7 154 24 3 154 15 54 154 58 40 153 41 26 154 46 18 -20 0 0 19 34 44 55 344 -6 154 50 21 154 42 14 155 24 49 154 7 54 155 12 51 -19 0 0 19 34 48 56 343 -5 155 16 53 155 8 48 155 51 13 154 34 36 155 39 38 -18 0 0 19 34 53 57 342 -5 155 43 40 155 35 37 156 17 54 155 1 31 156 6 42 -17 0 0 19 34 57 58 340 -4 156 10 43 156 2 41 156 44 51 155 28 42 156 34 3 -16 0 0 19 35 1 59 339 -3 156 38 3 156 30 3 157 12 6 155 56 8 157 1 42 -15 0 0 19 35 6 59 337 -3 157 5 42 156 57 42 157 39 40 156 23 52 157 29 40 -14 0 0 19 35 10 60 336 -2 157 33 39 157 25 40 158 7 35 156 51 54 157 57 58 -13 0 0 19 35 15 61 334 -1 158 1 58 157 53 59 158 35 51 157 20 15 158 26 39 -12 0 0 19 35 19 62 333 0 158 30 38 158 22 40 159 4 30 157 48 57 Uncertainty in time = +/- 2 secs [Prediction of 2008 Mar 31.0] Data for the target star ------------------------ * name: HIP 98517 * constellation : Aquila * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 20 00 51.8826 DE: +13 22 46.996 * position source: mpos:HIP pm:HIP plx:HIP * standard error: RA,DE ["]: ( .014, .012 ) * V mag [mag]: 7.2 * B mag [mag]: 7.2 * Apparent position with proper motion RA(deg): 300.3165241890 DE(deg): 13.3989334099 * Equation of equinoxes (radians) : 0.000038370981921 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1922) Zulu approx. diameter [km]: 12 approx. diameter ["]: .013 distance from Earth [AU]: 1.26700 * orbital information: orbit source: Preston date of fit: 2008 Mar 28 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 539 number of rejected observations: 10 time covered by the observations: 1949 Apr 25 - 2007 Jun 22 1 sigma uncertainty ellipse (major, minor, PA): 0.062, 0.029, 85° remarks: * orbital elements for (1922) Zulu : Mean anomaly = 4.08475856 deg Arg. of pericenter = 31.57606048 deg Long. of node = 226.54346568 deg Inclination = 35.42742572 deg Eccentricity = 0.48080225 Semimajor axis = 3.23849804 AU Perihelion dist = 1.68142090 AU Mag: H = 12.01, G = 0.15 Epoch of elements : MJD 54588.81700000 TDT (2008 May 02.817) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 May 2 1922 Zulu 19h 36.4m UT 7.2 20 0 51.883 13 22 47.00HIP 98517 7.2 15.3 12 0.5 1.267 3.438 88.71 145.0355 13.355 -114.86 15.67 19.6063 0.34840 -0.19623 7.23038 12.77854 -0.00447 -0.00141 2000 2.5936502008 424.00000 31.576060226.543466 35.4274260.48080225 3.2384980 1.681420912.2 5.00.15 RATE 1.6911750 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.064 0.031 85 5.24 0.055 0 54556.5020080502__98517 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 31, 03:42 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org