IOTA/IOTA-ES occultation update for (849) Ara / HIP 78708 event on 2009 Jan 27, 13:39 UT Visible from W USA Summary ------- On 2009 Jan 27 UT, the 62 km diameter asteroid (849) Ara will occult a 8.7 mag star in the constellation Scorpius for observers along a path across W USA. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.1 mag to 13.8 mag (the magnitude of the asteroid) for at most 2.0 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: . The event at a glimpse ---------------------- * Rank: 80 * date and approx. time of event: 2009 Jan 27, 13:37 - 2009 Jan 27, 13:38 UT * midpoint of event [JD]: 2454859.06894167 * magnitude of target star: 8.7 * magnitude drop [mag]: 5.1 * estimated maximum duration [s]: 2.0 * Moon: 2 % sunlit, 79° distance * Sun: 64° distance * rough path description: W USA Additional comments ------------------- 10" double star The occultation path -------------------- * approximate projected width [km]: 104 * 1 sigma uncertainty interval [path widths]: +/- 0.68 * 1 sigma uncertainty interval [seconds]: +/- 2.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .030 +/- .019) * 1 sigma uncertainty ellipse (major, minor, PA): ( .030", .019", 88° ) * approx speed of asteroid's shadow [km/s]: 31.1785 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 78708 by 849 Ara on 2009 Jan 27 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 -151 7 57 48 0 0 13 37 15 1 126 -40 -152 22 16 -149 52 49 ... .. .. -148 9 10 -148 54 42 47 0 0 13 37 15 3 127 -39 -150 9 5 -147 39 23 ... .. .. -145 55 22 Latitude Latitude Latitude Latitude -148 0 0 46 35 35 13 37 15 4 128 -38 46 2 27 47 9 13 45 18 11 47 55 52 -147 0 0 46 8 56 13 37 16 5 129 -38 45 35 57 46 42 26 44 51 51 47 28 52 -146 0 0 45 42 29 13 37 16 6 129 -37 45 9 37 46 15 50 44 25 43 47 2 4 -145 0 0 45 16 13 13 37 17 6 130 -37 44 43 30 45 49 25 43 59 45 46 35 27 -144 0 0 44 50 9 13 37 17 7 131 -36 44 17 34 45 23 13 43 34 1 46 9 2 -143 0 0 44 24 19 13 37 18 8 132 -35 43 51 53 44 57 15 43 8 30 45 42 51 -142 0 0 43 58 44 13 37 19 9 132 -35 43 26 25 44 31 31 42 43 13 45 16 55 -141 0 0 43 33 23 13 37 19 10 133 -34 43 1 13 44 6 2 42 18 12 44 51 13 -140 0 0 43 8 19 13 37 20 11 134 -33 42 36 17 43 40 49 41 53 26 44 25 48 -139 0 0 42 43 32 13 37 21 11 135 -33 42 11 38 43 15 53 41 28 58 44 0 40 -138 0 0 42 19 2 13 37 22 12 135 -32 41 47 17 42 51 15 41 4 47 43 35 50 -137 0 0 41 54 51 13 37 23 13 136 -31 41 23 14 42 26 56 40 40 54 43 11 19 -136 0 0 41 31 0 13 37 25 14 137 -30 40 59 30 42 2 56 40 17 21 42 47 7 -135 0 0 41 7 28 13 37 26 15 137 -30 40 36 6 41 39 16 39 54 7 42 23 15 -134 0 0 40 44 17 13 37 27 15 138 -29 40 13 3 41 15 57 39 31 15 41 59 44 -133 0 0 40 21 28 13 37 29 16 139 -28 39 50 22 40 53 0 39 8 43 41 36 35 -132 0 0 39 59 1 13 37 30 17 140 -27 39 28 3 40 30 24 38 46 34 41 13 49 -131 0 0 39 36 57 13 37 32 18 140 -27 39 6 6 40 8 12 38 24 47 40 51 26 -130 0 0 39 15 16 13 37 33 18 141 -26 38 44 33 39 46 24 38 3 23 40 29 26 -129 0 0 38 53 59 13 37 35 19 142 -25 38 23 23 39 25 0 37 42 23 40 7 51 -128 0 0 38 33 8 13 37 36 20 143 -24 38 2 39 39 4 1 37 21 48 39 46 41 -127 0 0 38 12 41 13 37 38 21 144 -23 37 42 19 38 43 27 37 1 38 39 25 57 -126 0 0 37 52 40 13 37 40 21 144 -23 37 22 25 38 23 19 36 41 53 39 5 39 -125 0 0 37 33 6 13 37 42 22 145 -22 37 2 58 38 3 38 36 22 34 38 45 48 -124 0 0 37 13 59 13 37 44 23 146 -21 36 43 57 37 44 23 36 3 42 38 26 24 -123 0 0 36 55 19 13 37 46 24 147 -20 36 25 24 37 25 37 35 45 17 38 7 27 -122 0 0 36 37 7 13 37 48 24 148 -19 36 7 18 37 7 18 35 27 19 37 48 59 -121 0 0 36 19 23 13 37 50 25 148 -18 35 49 40 36 49 28 35 9 50 37 31 0 -120 0 0 36 2 8 13 37 53 26 149 -18 35 32 32 36 32 7 34 52 49 37 13 30 -119 0 0 35 45 23 13 37 55 26 150 -17 35 15 52 36 15 15 34 36 17 36 56 30 -118 0 0 35 29 6 13 37 57 27 151 -16 34 59 41 35 58 53 34 20 13 36 40 0 -117 0 0 35 13 20 13 37 59 28 152 -15 34 44 1 35 43 1 34 4 40 36 24 0 -116 0 0 34 58 4 13 38 2 28 153 -14 34 28 50 35 27 40 33 49 36 36 8 30 -115 0 0 34 43 19 13 38 4 29 154 -13 34 14 10 35 12 50 33 35 3 35 53 32 -114 0 0 34 29 5 13 38 7 29 155 -12 34 0 1 34 58 30 33 21 0 35 39 6 -113 0 0 34 15 22 13 38 9 30 156 -11 33 46 23 34 44 42 33 7 28 35 25 11 -112 0 0 34 2 11 13 38 12 30 157 -11 33 33 16 34 31 26 32 54 28 35 11 48 -111 0 0 33 49 32 13 38 15 31 158 -10 33 20 41 34 18 43 32 41 59 34 58 58 -110 0 0 33 37 24 13 38 17 31 159 -9 33 8 38 34 6 31 32 30 1 34 46 40 -109 0 0 33 25 50 13 38 20 32 160 -8 32 57 7 33 54 52 32 18 36 34 34 55 -108 0 0 33 14 47 13 38 23 32 161 -7 32 46 9 33 43 46 32 7 42 34 23 43 -107 0 0 33 4 18 13 38 26 33 162 -6 32 35 43 33 33 13 31 57 21 34 13 5 -106 0 0 32 54 22 13 38 28 33 163 -5 32 25 50 33 23 13 31 47 33 34 3 0 -105 0 0 32 44 59 13 38 31 34 164 -5 32 16 30 33 13 46 31 38 17 33 53 28 -104 0 0 32 36 9 13 38 34 34 165 -4 32 7 44 33 4 53 31 29 35 33 44 31 -103 0 0 32 27 53 13 38 37 34 166 -3 31 59 31 32 56 34 31 21 25 33 36 8 -102 0 0 32 20 10 13 38 40 35 167 -2 31 51 51 32 48 49 31 13 49 33 28 19 -101 0 0 32 13 2 13 38 43 35 168 -1 31 44 45 32 41 38 31 6 46 33 21 4 -100 0 0 32 6 27 13 38 46 35 169 0 31 38 13 32 35 1 31 0 17 33 14 24 Uncertainty in time = +/- 2 secs [Prediction of 2008 Dec 27.0] Data for the target star ------------------------ * name: HIP 78708 * constellation : Scorpius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 16 04 02.6457 DE: -21 55 41.423 * position source: mpos:HIP2 pm:HIP2 plx:HIP2 * standard error: RA,DE ["]: ( .025, .017 ) * V mag [mag]: 8.7 * B mag [mag]: 9.6 * Apparent position with proper motion RA(deg): 241.1464015781 DE(deg): -21.9541977559 * Equation of equinoxes (radians) : 0.000064913501153 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (849) Ara approx. diameter [km]: 62 approx. diameter ["]: .028 distance from Earth [AU]: 3.10700 * orbital information: orbit source: Preston date of fit: 2008 Dec 25 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 854 number of rejected observations: 92 time covered by the observations: 1919 Jul 03 - 2008 Jul 25 1 sigma uncertainty ellipse (major, minor, PA): 0.016, 0.009, 83° remarks: * orbital elements for (849) Ara : Mean anomaly = 311.65758786 deg Arg. of pericenter = 64.20192107 deg Long. of node = 228.48743086 deg Inclination = 19.48874691 deg Eccentricity = 0.19594110 Semimajor axis = 3.15231912 AU Perihelion dist = 2.53465025 AU Mag: H = 8.05, G = 0.15 Epoch of elements : MJD 54858.56900000 TDT (2009 Jan 27.569) ------ occelmnt file for Occult BEGIN ----------------------------------- 2009 Jan 27 849 Ara 13h 39.3m UT 8.7 16 4 2.646-21 55 41.42HIP 78708 9.6 13.8 62 2.0 3.107 3.579 -0.51 -90.7761 -21.927 -21.61 -18.33 13.6546 0.00950 0.80123 17.59706 -0.18255 -0.00530 0.00099 2000 310.1485892009 119.00000 64.201921228.487431 19.4887470.19594110 3.1523191 2.5346502 8.1 5.00.15 RATE 1.7609980 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.030 0.019 88 1.68 0.019 0 54827.0020090127__78708 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Dec 27, 02:48 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org