IOTA/IOTA-ES occultation update for (87) Sylvia / UCAC2 40154917 event on 2012 Sep 19, 15:43 UT Visible from New Zealand Summary ------- On 2012 Sep 19 UT, the 263 km diameter asteroid (87) Sylvia will occult a 11.9 mag star in the constellation Gemini for observers along a path across New Zealand. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.6 mag to 13.2 mag (the magnitude of the asteroid) for at most 16.2 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, 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: 2012 Sep 19, 15:38 - 2012 Sep 19, 15:42 UT * geocentric midpoint of event [JD]: 2456190.15502917 * magnitude of target star: 11.9 * magnitude drop [mag]: 1.6 * estimated maximum duration [s]: 16.2 * Moon: 16 % sunlit, 133° distance * Sun: 86° distance * rough path description: New Zealand The occultation path -------------------- * approximate projected width [km]: 362 * 1 sigma uncertainty interval [path widths]: +/- 0.28 * 1 sigma uncertainty interval [seconds]: +/- 4.2 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .030 +/- .030) * 1 sigma uncertainty ellipse (major, minor, PA): ( .030", .030", 89° ) * approx speed of asteroid's shadow [km/s]: 16.2497 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC2 40154917 by 87 Sylvia on 2012 Sep 19 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 157 0 0 -47 50 4 15 38 32 1 53 -35 .. .. .. -45 50 49 .. .. .. -44 46 0 158 0 0 -47 19 42 15 38 32 1 52 -35 -49 23 57 -45 20 32 .. .. .. -44 15 46 159 0 0 -46 49 7 15 38 32 2 51 -35 -48 53 15 -44 50 3 -50 5 18 -43 45 19 160 0 0 -46 18 19 15 38 33 3 51 -35 -48 22 19 -44 19 22 -49 34 17 -43 14 41 161 0 0 -45 47 19 15 38 33 4 50 -35 -47 51 10 -43 48 30 -49 3 2 -42 43 54 162 0 0 -45 16 8 15 38 34 5 49 -35 -47 19 49 -43 17 28 -48 31 35 -42 12 56 163 0 0 -44 44 48 15 38 35 6 48 -34 -46 48 17 -42 46 18 -47 59 56 -41 41 51 164 0 0 -44 13 19 15 38 35 7 48 -34 -46 16 36 -42 15 0 -47 28 7 -41 10 39 165 0 0 -43 41 43 15 38 36 8 47 -34 -45 44 46 -41 43 36 -46 56 8 -40 39 20 166 0 0 -43 10 0 15 38 38 8 46 -34 -45 12 48 -41 12 5 -46 24 1 -40 7 57 167 0 0 -42 38 11 15 38 39 9 46 -33 -44 40 44 -40 40 31 -45 51 47 -39 36 29 168 0 0 -42 6 19 15 38 40 10 45 -33 -44 8 35 -40 8 53 -45 19 27 -39 4 59 169 0 0 -41 34 23 15 38 42 11 44 -33 -43 36 21 -39 37 13 -44 47 3 -38 33 26 170 0 0 -41 2 26 15 38 44 12 44 -32 -43 4 5 -39 5 31 -44 14 35 -38 1 53 171 0 0 -40 30 27 15 38 46 13 43 -32 -42 31 48 -38 33 50 -43 42 6 -37 30 21 172 0 0 -39 58 29 15 38 48 14 42 -32 -41 59 29 -38 2 10 -43 9 35 -36 58 49 173 0 0 -39 26 33 15 38 50 15 41 -31 -41 27 12 -37 30 32 -42 37 5 -36 27 21 174 0 0 -38 54 39 15 38 52 16 41 -31 -40 54 57 -36 58 57 -42 4 36 -35 55 56 175 0 0 -38 22 50 15 38 55 17 40 -30 -40 22 45 -36 27 27 -41 32 10 -35 24 36 176 0 0 -37 51 5 15 38 57 18 39 -30 -39 50 38 -35 56 3 -40 59 49 -34 53 23 177 0 0 -37 19 27 15 39 0 18 39 -29 -39 18 36 -35 24 46 -40 27 32 -34 22 16 178 0 0 -36 47 56 15 39 3 19 38 -29 -38 46 41 -34 53 36 -39 55 23 -33 51 17 179 0 0 -36 16 34 15 39 6 20 37 -28 -38 14 55 -34 22 36 -39 23 21 -33 20 28 180 0 0 -35 45 22 15 39 9 21 36 -27 -37 43 17 -33 51 46 -38 51 28 -32 49 50 -179 0 0 -35 14 20 15 39 13 22 36 -27 -37 11 51 -33 21 7 -38 19 46 -32 19 22 -178 0 0 -34 43 31 15 39 16 23 35 -26 -36 40 36 -32 50 41 -37 48 15 -31 49 8 -177 0 0 -34 12 55 15 39 20 24 34 -26 -36 9 33 -32 20 28 -37 16 57 -31 19 7 -176 0 0 -33 42 33 15 39 24 25 33 -25 -35 38 45 -31 50 29 -36 45 53 -30 49 20 -175 0 0 -33 12 26 15 39 28 26 33 -24 -35 8 12 -31 20 46 -36 15 3 -30 19 49 -174 0 0 -32 42 36 15 39 32 26 32 -24 -34 37 55 -30 51 19 -35 44 30 -29 50 35 -173 0 0 -32 13 3 15 39 36 27 31 -23 -34 7 55 -30 22 10 -35 14 14 -29 21 39 -172 0 0 -31 43 48 15 39 40 28 30 -22 -33 38 14 -29 53 20 -34 44 16 -28 53 1 -171 0 0 -31 14 53 15 39 45 29 30 -21 -33 8 52 -29 24 49 -34 14 37 -28 24 42 -170 0 0 -30 46 18 15 39 49 30 29 -21 -32 39 50 -28 56 38 -33 45 19 -27 56 44 -169 0 0 -30 18 4 15 39 54 31 28 -20 -32 11 9 -28 28 48 -33 16 21 -27 29 6 -168 0 0 -29 50 12 15 39 59 32 27 -19 -31 42 50 -28 1 20 -32 47 47 -27 1 51 -167 0 0 -29 22 43 15 40 4 32 26 -18 -31 14 55 -27 34 16 -32 19 35 -26 34 59 -166 0 0 -28 55 38 15 40 9 33 25 -17 -30 47 23 -27 7 35 -31 51 47 -26 8 31 -165 0 0 -28 28 58 15 40 14 34 24 -17 -30 20 17 -26 41 18 -31 24 24 -25 42 27 -164 0 0 -28 2 43 15 40 20 35 23 -16 -29 53 35 -26 15 27 -30 57 27 -25 16 48 -163 0 0 -27 36 54 15 40 25 35 22 -15 -29 27 21 -25 50 2 -30 30 57 -24 51 35 -162 0 0 -27 11 32 15 40 31 36 21 -14 -29 1 33 -25 25 3 -30 4 53 -24 26 48 -161 0 0 -26 46 38 15 40 36 37 21 -13 -28 36 13 -25 0 32 -29 39 18 -24 2 29 -160 0 0 -26 22 12 15 40 42 38 19 -12 -28 11 22 -24 36 28 -29 14 12 -23 38 38 -159 0 0 -25 58 15 15 40 48 38 18 -11 -27 47 0 -24 12 54 -28 49 35 -23 15 15 -158 0 0 -25 34 47 15 40 54 39 17 -11 -27 23 8 -23 49 48 -28 25 28 -22 52 21 -157 0 0 -25 11 49 15 41 0 40 16 -10 -26 59 47 -23 27 13 -28 1 52 -22 29 57 -156 0 0 -24 49 23 15 41 6 40 15 -9 -26 36 56 -23 5 7 -27 38 47 -22 8 2 -155 0 0 -24 27 27 15 41 12 41 14 -8 -26 14 38 -22 43 33 -27 16 14 -21 46 39 -154 0 0 -24 6 3 15 41 18 41 13 -7 -25 52 51 -22 22 30 -26 54 14 -21 25 47 -153 0 0 -23 45 11 15 41 24 42 12 -6 -25 31 37 -22 1 58 -26 32 47 -21 5 26 -152 0 0 -23 24 52 15 41 31 42 11 -5 -25 10 56 -21 41 59 -26 11 53 -20 45 37 -151 0 0 -23 5 6 15 41 37 43 9 -4 -24 50 49 -21 22 32 -25 51 32 -20 26 21 -150 0 0 -22 45 54 15 41 43 43 8 -3 -24 31 16 -21 3 39 -25 31 47 -20 7 37 -149 0 0 -22 27 15 15 41 50 44 7 -2 -24 12 17 -20 45 19 -25 12 36 -19 49 27 -148 0 0 -22 9 11 15 41 57 44 6 -1 -23 53 53 -20 27 32 -24 54 0 -19 31 50 -147 0 0 -21 51 41 15 42 3 45 4 0 -23 36 4 -20 10 20 -24 35 59 -19 14 47 Uncertainty in time = +/- 5 secs Prediction of 2012 Jul 22.0 Data for the target star ------------------------ * name: UCAC2 40154917 * constellation : Gemini * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 06 02 43.6701 DE: +23 36 09.095 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .029, .029 ) * V mag [mag]: 11.9 * B mag [mag]: 0.0 * Apparent position with proper motion RA(deg): 90.8799918519 DE(deg): 23.6003754783 * Equation of equinoxes (radians) : 0.000065373815031 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (87) Sylvia approx. diameter [km]: 263 approx. diameter ["]: .106 distance from Earth [AU]: 3.41700 * orbital information: orbit source: Preston date of fit: 2012 Jul 21 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 2200 number of rejected observations: 103 time covered by the observations: 1909 Apr 21 - 2012 Feb 02 1 sigma uncertainty ellipse (major, minor, PA): 0.010, 0.006, 78° remarks: * orbital elements for (87) Sylvia : Mean anomaly = 85.08712143 deg Arg. of pericenter = 265.77307227 deg Long. of node = 73.14297011 deg Inclination = 10.88578494 deg Eccentricity = 0.08714408 Semimajor axis = 3.49808705 AU Perihelion dist = 3.19324946 AU Mag: H = 6.70, G = 0.15 Epoch of elements : MJD 56189.65500000 TDT (2012 Sep 19.655) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 19 87 Sylvia 15h 43.2m UT 11.9 6 2 43.670 23 36 9.10UCAC2 40154917 0.0 13.2 263 16.2 3.417 1.687 4.35 -144.0777 23.601 -57.41 1.15 15.7207 0.12350 -0.67663 9.01469 1.69017 -0.00585 0.00003 2000 83.6326322012 910.00000265.773072 73.142970 10.8857850.08714408 3.4980871 3.1932495 6.9 5.00.15 RATE 1.5064620 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.030 0.030 89 1.28 0.030 2 7 706 18 1356 0 1-5 056130.0020120919_154917 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 22, 04:07 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org