IOTA/IOTA-ES occultation update for (456) Abnoba / HIP 116979 event on 2008 May 13, 18:32 UT Visible from N Australia Summary ------- On 2008 May 13 UT, the 38 km diameter asteroid (456) Abnoba will occult a 8.1 mag star in the constellation Pegasus for observers along a path across N Australia. In the case of an occultation, the combined light of the asteroid and the star will drop by 6.9 mag to 15.0 mag (the magnitude of the asteroid) for at most 1.1 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: 65 * date and approx. time of event: 2008 May 13, 18:29 - 2008 May 13, 18:31 UT * midpoint of event [JD]: 2454600.2728375 * magnitude of target star: 8.1 * magnitude drop [mag]: 6.9 * estimated maximum duration [s]: 1.1 * Moon: 67 % sunlit, 160° distance * Sun: 54° distance * rough path description: N Australia Additional comments ------------------- pm diff The occultation path -------------------- * approximate projected width [km]: 38 * 1 sigma uncertainty interval [path widths]: +/- 0.92 * 1 sigma uncertainty interval [seconds]: +/- 1.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .021 +/- .013) * 1 sigma uncertainty ellipse (major, minor, PA): ( .021", .013", 86° ) * approx speed of asteroid's shadow [km/s]: 33.4810 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 116979 by 456 Abnoba on 2008 May 13 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 ' " Latitude Latitude Latitude Latitude 121 0 0 -18 23 27 18 29 45 1 79 -53 -18 34 4 -18 12 49 -18 53 37 -17 53 14 122 0 0 -18 11 30 18 29 45 2 78 -52 -18 22 9 -18 0 51 -18 41 43 -17 41 15 123 0 0 -17 59 4 18 29 45 3 78 -51 -18 9 44 -17 48 24 -18 29 20 -17 28 45 124 0 0 -17 46 9 18 29 45 4 78 -50 -17 56 50 -17 35 27 -18 16 28 -17 15 46 125 0 0 -17 32 43 18 29 45 5 77 -49 -17 43 25 -17 22 1 -18 3 6 -17 2 18 126 0 0 -17 18 48 18 29 46 6 77 -48 -17 29 32 -17 8 5 -17 49 15 -16 48 19 127 0 0 -17 4 24 18 29 46 7 77 -47 -17 15 8 -16 53 39 -17 34 54 -16 33 51 128 0 0 -16 49 29 18 29 46 8 76 -46 -17 0 15 -16 38 43 -17 20 3 -16 18 53 129 0 0 -16 34 5 18 29 47 9 76 -45 -16 44 53 -16 23 18 -17 4 43 -16 3 25 130 0 0 -16 18 12 18 29 47 10 76 -44 -16 29 0 -16 7 23 -16 48 53 -15 47 28 131 0 0 -16 1 48 18 29 48 11 76 -43 -16 12 39 -15 50 58 -16 32 34 -15 31 0 132 0 0 -15 44 55 18 29 49 12 75 -42 -15 55 47 -15 34 4 -16 15 45 -15 14 3 133 0 0 -15 27 33 18 29 49 13 75 -41 -15 38 26 -15 16 40 -15 58 27 -14 56 36 134 0 0 -15 9 41 18 29 50 14 75 -40 -15 20 35 -14 58 46 -15 40 39 -14 38 40 135 0 0 -14 51 19 18 29 51 15 75 -39 -15 2 15 -14 40 23 -15 22 22 -14 20 14 136 0 0 -14 32 28 18 29 52 16 74 -38 -14 43 26 -14 21 30 -15 3 35 -14 1 19 137 0 0 -14 13 8 18 29 53 17 74 -37 -14 24 7 -14 2 9 -14 44 19 -13 41 54 138 0 0 -13 53 19 18 29 54 18 74 -36 -14 4 19 -13 42 18 -14 24 34 -13 22 0 139 0 0 -13 33 0 18 29 55 19 74 -35 -13 44 2 -13 21 57 -14 4 20 -13 1 37 140 0 0 -13 12 12 18 29 56 20 73 -34 -13 23 16 -13 1 8 -13 43 37 -12 40 45 141 0 0 -12 50 56 18 29 57 21 73 -33 -13 2 2 -12 39 50 -13 22 26 -12 19 24 142 0 0 -12 29 11 18 29 59 22 73 -32 -12 40 18 -12 18 3 -13 0 45 -11 57 34 143 0 0 -12 6 57 18 30 0 23 73 -31 -12 18 6 -11 55 48 -12 38 36 -11 35 15 144 0 0 -11 44 15 18 30 1 24 73 -30 -11 55 26 -11 33 4 -12 15 59 -11 12 28 145 0 0 -11 21 5 18 30 3 25 73 -29 -11 32 18 -11 9 52 -11 52 54 -10 49 14 146 0 0 -10 57 27 18 30 4 26 72 -28 -11 8 41 -10 46 13 -11 29 21 -10 25 31 147 0 0 -10 33 22 18 30 6 27 72 -26 -10 44 37 -10 22 6 -11 5 20 -10 1 20 148 0 0 -10 8 49 18 30 8 28 72 -25 -10 20 6 - 9 57 31 -10 40 52 - 9 36 43 149 0 0 - 9 43 49 18 30 9 29 72 -24 - 9 55 8 - 9 32 29 -10 15 57 - 9 11 38 150 0 0 - 9 18 22 18 30 11 31 72 -23 - 9 29 43 - 9 7 1 - 9 50 35 - 8 46 6 151 0 0 - 8 52 29 18 30 13 32 72 -22 - 9 3 52 - 8 41 6 - 9 24 47 - 8 20 9 152 0 0 - 8 26 10 18 30 15 33 72 -21 - 8 37 35 - 8 14 46 - 8 58 33 - 7 53 45 153 0 0 - 7 59 26 18 30 17 34 72 -20 - 8 10 52 - 7 48 0 - 8 31 53 - 7 26 55 154 0 0 - 7 32 16 18 30 19 35 72 -19 - 7 43 44 - 7 20 48 - 8 4 48 - 6 59 41 155 0 0 - 7 4 42 18 30 21 36 72 -18 - 7 16 11 - 6 53 12 - 7 37 19 - 6 32 2 156 0 0 - 6 36 44 18 30 24 37 71 -17 - 6 48 15 - 6 25 12 - 7 9 25 - 6 3 59 157 0 0 - 6 8 21 18 30 26 38 71 -16 - 6 19 54 - 5 56 48 - 6 41 8 - 5 35 32 158 0 0 - 5 39 36 18 30 28 39 71 -15 - 5 51 10 - 5 28 1 - 6 12 27 - 5 6 42 159 0 0 - 5 10 28 18 30 31 40 72 -13 - 5 22 4 - 4 58 52 - 5 43 23 - 4 37 29 160 0 0 - 4 40 58 18 30 33 41 72 -12 - 4 52 36 - 4 29 20 - 5 13 58 - 4 7 55 161 0 0 - 4 11 7 18 30 36 43 72 -11 - 4 22 46 - 3 59 27 - 4 44 11 - 3 37 59 162 0 0 - 3 40 55 18 30 38 44 72 -10 - 3 52 35 - 3 29 14 - 4 14 3 - 3 7 43 163 0 0 - 3 10 23 18 30 41 45 72 -9 - 3 22 5 - 2 58 40 - 3 43 35 - 2 37 7 164 0 0 - 2 39 32 18 30 43 46 72 -8 - 2 51 15 - 2 27 48 - 3 12 48 - 2 6 12 165 0 0 - 2 8 22 18 30 46 47 72 -7 - 2 20 6 - 1 56 36 - 2 41 42 - 1 34 58 166 0 0 - 1 36 54 18 30 49 48 72 -6 - 1 48 40 - 1 25 7 - 2 10 18 - 1 3 26 167 0 0 - 1 5 9 18 30 52 49 72 -4 - 1 16 57 - 0 53 21 - 1 38 37 - 0 31 38 168 0 0 - 0 33 9 18 30 55 50 73 -3 - 0 44 57 - 0 21 19 - 1 6 40 0 0 26 169 0 0 - 0 0 52 18 30 58 52 73 -2 - 0 12 42 0 10 58 - 0 34 27 0 32 46 170 0 0 0 31 38 18 31 1 53 73 -1 0 19 47 0 43 30 - 0 2 0 1 5 20 Uncertainty in time = +/- 2 secs [Prediction of 2008 Apr 9.0] Data for the target star ------------------------ * name: HIP 116979 * constellation : Pegasus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 23 42 50.7402 DE: +10 28 54.727 * position source: mpos:HIP pm:HIP plx:HIP * standard error: RA,DE ["]: ( .018, .011 ) * V mag [mag]: 8.1 * B mag [mag]: 9.3 * Apparent position with proper motion RA(deg): 355.8170599678 DE(deg): 10.5269830503 * Equation of equinoxes (radians) : 0.000040860764868 * remarks:pm diff Data for the minor planet ------------------------- * general information: (number) name: (456) Abnoba approx. diameter [km]: 38 approx. diameter ["]: .016 distance from Earth [AU]: 3.31400 * orbital information: orbit source: Preston date of fit: 2008 Apr 08 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 797 number of rejected observations: 67 time covered by the observations: 1900 Jun 15 - 2007 Oct 04 1 sigma uncertainty ellipse (major, minor, PA): 0.011, 0.008, 77° remarks: * orbital elements for (456) Abnoba : Mean anomaly = 85.46291254 deg Arg. of pericenter = 7.15851143 deg Long. of node = 229.34793734 deg Inclination = 14.44637014 deg Eccentricity = 0.18153949 Semimajor axis = 2.78571913 AU Perihelion dist = 2.28000109 AU Mag: H = 9.05, G = 0.15 Epoch of elements : MJD 54599.77300000 TDT (2008 May 13.773) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 May 13 456 Abnoba 18h 32.9m UT 8.1 23 42 50.740 10 28 54.73HIP 116979 9.3 15.0 38 1.1 3.314 3.022 22.96 -154.3949 10.476 -99.13 18.61 18.5481 -0.06640 0.13133 16.80051 8.65226 -0.00439 -0.00122 2000 83.3912172008 5 4.00000 7.158511229.347937 14.4463700.18153949 2.7857191 2.2800011 9.2 5.00.15 RATE 2.1198160 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.021 0.013 86 1.92 0.015 0 54565.5020080513_116979 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Apr 09, 17:09 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org