IOTA/IOTA-ES occultation update for (1639) Bower / TYC 6852-03560-1 event on 2012 Sep 29, 11:58 UT Visible from Japan, China, SE Asia Summary ------- On 2012 Sep 29 UT, the 39 km diameter asteroid (1639) Bower will occult a 10.5 mag star in the constellation Sagittarius for observers along a path across Japan, China, SE Asia. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.9 mag to 16.4 mag (the magnitude of the asteroid) for at most 2.2 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: 40 * date and approx. time of event: 2012 Sep 29, 11:59 - 2012 Sep 29, 12:03 UT * geocentric midpoint of event [JD]: 2456199.99915417 * magnitude of target star: 10.5 * magnitude drop [mag]: 5.9 * estimated maximum duration [s]: 2.2 * Moon: 99 % sunlit, 85° distance * Sun: 87° distance * rough path description: Japan, China, SE Asia Additional comments ------------------- close double star The occultation path -------------------- * approximate projected width [km]: 49 * 1 sigma uncertainty interval [path widths]: +/- 1.63 * 1 sigma uncertainty interval [seconds]: +/- 3.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .034 +/- .032) * 1 sigma uncertainty ellipse (major, minor, PA): ( .034", .032", 87° ) * approx speed of asteroid's shadow [km/s]: 17.2142 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6852-03560-1 by 1639 Bower on 2012 Sep 29 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 88 0 0 11 17 2 11 59 58 51 183 -1 11 2 57 11 31 9 10 17 23 12 17 30 89 0 0 11 39 41 12 0 5 51 184 -2 11 25 33 11 53 51 10 39 48 12 40 24 90 0 0 12 3 1 12 0 11 50 186 -3 11 48 50 12 17 15 11 2 55 13 3 59 91 0 0 12 27 3 12 0 18 50 187 -4 12 12 49 12 41 21 11 26 42 13 28 16 92 0 0 12 51 46 12 0 25 49 188 -5 12 37 28 13 6 7 11 51 10 13 53 14 93 0 0 13 17 9 12 0 31 48 190 -6 13 2 48 13 31 34 12 16 18 14 18 54 94 0 0 13 43 13 12 0 38 48 191 -7 13 28 47 13 57 41 12 42 6 14 45 13 95 0 0 14 9 56 12 0 44 47 192 -8 13 55 27 14 24 28 13 8 33 15 12 13 96 0 0 14 37 18 12 0 51 47 193 -9 14 22 45 14 51 54 13 35 39 15 39 52 97 0 0 15 5 20 12 0 57 46 194 -10 14 50 42 15 20 0 14 3 24 16 8 11 98 0 0 15 33 59 12 1 3 45 195 -11 15 19 18 15 48 43 14 31 47 16 37 8 99 0 0 16 3 16 12 1 10 44 197 -12 15 48 31 16 18 5 15 0 47 17 6 43 100 0 0 16 33 11 12 1 16 44 198 -13 16 18 22 16 48 3 15 30 24 17 36 55 101 0 0 17 3 42 12 1 22 43 199 -14 16 48 49 17 18 38 16 0 38 18 7 45 102 0 0 17 34 49 12 1 28 42 200 -15 17 19 51 17 49 50 16 31 27 18 39 10 103 0 0 18 6 31 12 1 34 41 201 -16 17 51 29 18 21 36 17 2 51 19 11 10 104 0 0 18 38 47 12 1 40 40 202 -17 18 23 41 18 53 56 17 34 50 19 43 45 105 0 0 19 11 37 12 1 45 40 202 -18 18 56 26 19 26 51 18 7 21 20 16 54 106 0 0 19 44 59 12 1 51 39 203 -19 19 29 44 20 0 17 18 40 26 20 50 36 107 0 0 20 18 53 12 1 57 38 204 -20 20 3 34 20 34 16 19 14 2 21 24 49 108 0 0 20 53 18 12 2 2 37 205 -21 20 37 55 21 8 45 19 48 8 21 59 33 109 0 0 21 28 13 12 2 7 36 206 -21 21 12 45 21 43 45 20 22 44 22 34 47 110 0 0 22 3 36 12 2 13 35 207 -22 21 48 4 22 19 12 20 57 50 23 10 30 111 0 0 22 39 27 12 2 18 34 207 -23 22 23 51 22 55 8 21 33 22 23 46 40 112 0 0 23 15 45 12 2 23 33 208 -24 23 0 4 23 31 30 22 9 21 24 23 17 113 0 0 23 52 27 12 2 27 32 209 -25 23 36 42 24 8 17 22 45 46 25 0 19 114 0 0 24 29 34 12 2 32 31 210 -26 24 13 44 24 45 28 23 22 34 25 37 45 115 0 0 25 7 3 12 2 37 30 210 -26 24 51 9 25 23 1 23 59 45 26 15 33 116 0 0 25 44 54 12 2 41 29 211 -27 25 28 56 26 0 56 24 37 18 26 53 42 117 0 0 26 23 5 12 2 45 28 212 -28 26 7 2 26 39 11 25 15 11 27 32 11 118 0 0 27 1 34 12 2 50 27 212 -29 26 45 27 27 17 45 25 53 23 28 10 59 119 0 0 27 40 20 12 2 54 26 213 -30 27 24 9 27 56 35 26 31 52 28 50 3 120 0 0 28 19 21 12 2 57 25 214 -30 28 3 7 28 35 41 27 10 37 29 29 22 121 0 0 28 58 37 12 3 1 24 214 -31 28 42 18 29 15 0 27 49 36 30 8 55 122 0 0 29 38 5 12 3 5 23 215 -32 29 21 43 29 54 32 28 28 48 30 48 41 123 0 0 30 17 44 12 3 8 22 216 -32 30 1 18 30 34 15 29 8 11 31 28 36 124 0 0 30 57 32 12 3 11 21 216 -33 30 41 2 31 14 7 29 47 44 32 8 40 125 0 0 31 37 28 12 3 14 20 217 -33 31 20 55 31 54 6 30 27 25 32 48 52 126 0 0 32 17 30 12 3 17 19 218 -34 32 0 53 32 34 11 31 7 13 33 29 9 127 0 0 32 57 36 12 3 20 18 218 -35 32 40 55 33 14 21 31 47 5 34 9 29 128 0 0 33 37 44 12 3 22 17 219 -35 33 21 1 33 54 32 32 27 0 34 49 52 129 0 0 34 17 54 12 3 25 15 220 -36 34 1 7 34 34 45 33 6 57 35 30 14 130 0 0 34 58 2 12 3 27 14 220 -36 34 41 13 35 14 56 33 46 54 36 10 35 131 0 0 35 38 8 12 3 29 13 221 -37 35 21 16 35 55 5 34 26 49 36 50 53 132 0 0 36 18 10 12 3 31 12 221 -37 36 1 16 36 35 10 35 6 40 37 31 7 133 0 0 36 58 6 12 3 32 11 222 -37 36 41 10 37 15 8 35 46 27 38 11 13 134 0 0 37 37 55 12 3 34 10 223 -38 37 20 56 37 54 59 36 26 7 38 51 11 135 0 0 38 17 35 12 3 35 9 223 -38 38 0 34 38 34 41 37 5 38 39 31 0 136 0 0 38 57 4 12 3 37 8 224 -38 38 40 1 39 14 11 37 44 59 40 10 37 137 0 0 39 36 20 12 3 38 7 225 -39 39 19 16 39 53 30 38 24 10 40 50 0 138 0 0 40 15 23 12 3 39 6 225 -39 39 58 18 40 32 34 39 3 7 41 29 10 139 0 0 40 54 11 12 3 39 5 226 -39 40 37 4 41 11 23 39 41 50 42 8 3 140 0 0 41 32 42 12 3 40 4 227 -39 41 15 34 41 49 55 40 20 17 42 46 38 141 0 0 42 10 55 12 3 41 3 227 -39 41 53 46 42 28 9 .. .. .. 43 24 54 142 0 0 42 48 49 12 3 41 2 228 -39 42 31 39 43 6 3 .. .. .. 44 2 50 143 0 0 43 26 21 12 3 41 1 229 -40 43 9 12 43 43 36 .. .. .. 44 40 25 144 0 0 44 3 32 12 3 41 0 229 -40 43 46 23 44 20 47 .. .. .. .. .. .. Uncertainty in time = +/- 4 secs Prediction of 2012 Aug 7.0 Data for the target star ------------------------ * name: TYC 6852-03560-1 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 17 41.6997 DE: -27 45 58.500 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .028, .030 ) * V mag [mag]: 10.5 * B mag [mag]: 10.6 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1639) Bower approx. diameter [km]: 39 approx. diameter ["]: .020 distance from Earth [AU]: 2.68300 * orbital information: orbit source: Preston date of fit: 2012 Aug 06 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 974 number of rejected observations: 47 time covered by the observations: 1906 Dec 21 - 2012 Jun 18 1 sigma uncertainty ellipse (major, minor, PA): 0.019, 0.013, 82° remarks: * orbital elements for (1639) Bower : Mean anomaly = 236.51992177 deg Arg. of pericenter = 106.63502178 deg Long. of node = 324.21893995 deg Inclination = 8.43726645 deg Eccentricity = 0.15003684 Semimajor axis = 2.57256755 AU Perihelion dist = 2.18658766 AU Mag: H = 11.01, G = 0.15 Epoch of elements : MJD 56199.49900000 TDT (2012 Sep 29.499) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 29 1639 Bower 11h 58.8m UT 10.5 18 17 41.700-27 45 58.50TYC 6852-03560-1 10.6 16.4 39 2.2 2.683 2.317 8.27 86.0759 -27.768 -2.15 -2.68 11.9797 -0.15035 0.57882 9.38254 2.52422 0.00570 0.00015 2000 234.2509362012 920.00000106.635022324.218940 8.4372660.15003684 2.5725676 2.186587611.0 5.00.15 RATE 2.3886580 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.034 0.032 87 2.63 0.033 0 0-3 0 056146.0020120929_3560-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Aug 06, 21:14 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org