IOTA/IOTA-ES occultation update for (122) Gerda / TYC 1293-00686-1 event on 2012 Sep 11, 02:45 UT Visible from S Africa Summary ------- On 2012 Sep 11 UT, the 85 km diameter asteroid (122) Gerda will occult a 9.0 mag star in the constellation Taurus for observers along a path across S Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 4.7 mag to 13.7 mag (the magnitude of the asteroid) for at most 5.9 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: 92 * date and approx. time of event: 2012 Sep 11, 02:40 - 2012 Sep 11, 02:46 UT * geocentric midpoint of event [JD]: 2456181.6151125 * magnitude of target star: 9.0 * magnitude drop [mag]: 4.7 * estimated maximum duration [s]: 5.9 * Moon: 26 % sunlit, 31° distance * Sun: 92° distance * rough path description: S Africa The occultation path -------------------- * approximate projected width [km]: 114 * 1 sigma uncertainty interval [path widths]: +/- 0.50 * 1 sigma uncertainty interval [seconds]: +/- 4.3 * 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]: 14.3677 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 1293-00686-1 by 122 Gerda on 2012 Sep 11 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 - 25 0 0 -40 37 53 2 40 18 1 61 -51 -41 13 7 -40 3 1 -41 48 44 .. .. .. - 24 0 0 -40 12 59 2 40 19 1 60 -51 -40 48 11 -39 38 10 -41 23 46 .. .. .. - 23 0 0 -39 48 5 2 40 19 2 60 -51 -40 23 14 -39 13 17 -40 58 46 -38 38 51 - 22 0 0 -39 23 10 2 40 19 3 59 -51 -39 58 16 -38 48 25 -40 33 45 -38 14 1 - 21 0 0 -38 58 15 2 40 20 4 58 -51 -39 33 18 -38 23 33 -40 8 44 -37 49 12 - 20 0 0 -38 33 21 2 40 21 5 58 -51 -39 8 22 -37 58 42 -39 43 44 -37 24 24 - 19 0 0 -38 8 30 2 40 21 6 57 -51 -38 43 27 -37 33 54 -39 18 46 -36 59 38 - 18 0 0 -37 43 40 2 40 22 7 57 -51 -38 18 34 -37 9 8 -38 53 50 -36 34 56 - 17 0 0 -37 18 55 2 40 24 8 56 -51 -37 53 45 -36 44 25 -38 28 57 -36 10 16 - 16 0 0 -36 54 13 2 40 25 9 55 -50 -37 29 0 -36 19 47 -38 4 8 -35 45 41 - 15 0 0 -36 29 36 2 40 26 9 55 -50 -37 4 19 -35 55 14 -37 39 24 -35 21 12 - 14 0 0 -36 5 5 2 40 28 10 54 -50 -36 39 44 -35 30 46 -37 14 45 -34 56 48 - 13 0 0 -35 40 40 2 40 30 11 53 -50 -36 15 15 -35 6 25 -36 50 12 -34 32 30 - 12 0 0 -35 16 22 2 40 32 12 53 -49 -35 50 54 -34 42 11 -36 25 46 -34 8 20 - 11 0 0 -34 52 13 2 40 34 13 52 -49 -35 26 40 -34 18 6 -36 1 28 -33 44 18 - 10 0 0 -34 28 11 2 40 36 14 52 -48 -35 2 34 -33 54 8 -35 37 19 -33 20 25 - 9 0 0 -34 4 19 2 40 38 15 51 -48 -34 38 38 -33 30 21 -35 13 18 -32 56 41 - 8 0 0 -33 40 38 2 40 41 16 50 -48 -34 14 52 -33 6 43 -34 49 28 -32 33 8 - 7 0 0 -33 17 7 2 40 44 17 50 -47 -33 51 17 -32 43 16 -34 25 48 -32 9 45 - 6 0 0 -32 53 47 2 40 46 18 49 -47 -33 27 53 -32 20 1 -34 2 20 -31 46 34 - 5 0 0 -32 30 40 2 40 49 18 49 -46 -33 4 42 -31 56 58 -33 39 3 -31 23 35 - 4 0 0 -32 7 46 2 40 53 19 48 -46 -32 41 43 -31 34 9 -33 16 0 -31 0 50 - 3 0 0 -31 45 6 2 40 56 20 47 -45 -32 18 58 -31 11 33 -32 53 10 -30 38 18 - 2 0 0 -31 22 39 2 40 59 21 47 -45 -31 56 27 -30 49 11 -32 30 35 -30 16 1 - 1 0 0 -31 0 28 2 41 3 22 46 -44 -31 34 11 -30 27 4 -32 8 14 -29 53 58 0 0 0 -30 38 33 2 41 7 23 45 -43 -31 12 11 -30 5 13 -31 46 10 -29 32 12 1 0 0 -30 16 53 2 41 11 24 45 -43 -30 50 27 -29 43 38 -31 24 21 -29 10 41 2 0 0 -29 55 31 2 41 15 25 44 -42 -30 29 1 -29 22 21 -31 2 49 -28 49 28 3 0 0 -29 34 27 2 41 19 25 43 -41 -30 7 51 -29 1 20 -30 41 35 -28 28 32 4 0 0 -29 13 40 2 41 23 26 43 -41 -29 47 0 -28 40 38 -30 20 39 -28 7 54 5 0 0 -28 53 12 2 41 28 27 42 -40 -29 26 28 -28 20 15 -30 0 2 -27 47 35 6 0 0 -28 33 4 2 41 32 28 41 -39 -29 6 15 -28 0 11 -29 39 45 -27 27 36 7 0 0 -28 13 15 2 41 37 29 40 -38 -28 46 22 -27 40 27 -29 19 47 -27 7 56 8 0 0 -27 53 47 2 41 42 30 40 -38 -28 26 49 -27 21 3 -29 0 10 -26 48 37 9 0 0 -27 34 40 2 41 47 30 39 -37 -28 7 38 -27 2 1 -28 40 53 -26 29 38 10 0 0 -27 15 55 2 41 52 31 38 -36 -27 48 48 -26 43 19 -28 21 59 -26 11 1 11 0 0 -26 57 31 2 41 57 32 37 -35 -27 30 20 -26 25 0 -28 3 27 -25 52 46 12 0 0 -26 39 30 2 42 3 33 36 -35 -27 12 14 -26 7 4 -27 45 17 -25 34 54 13 0 0 -26 21 52 2 42 8 34 36 -34 -26 54 32 -25 49 30 -27 27 30 -25 17 24 14 0 0 -26 4 38 2 42 14 34 35 -33 -26 37 13 -25 32 19 -27 10 7 -25 0 17 15 0 0 -25 47 47 2 42 20 35 34 -32 -26 20 19 -25 15 33 -26 53 8 -24 43 35 16 0 0 -25 31 21 2 42 25 36 33 -31 -26 3 48 -24 59 10 -26 36 33 -24 27 16 17 0 0 -25 15 19 2 42 31 37 32 -30 -25 47 43 -24 43 13 -26 20 24 -24 11 23 18 0 0 -24 59 43 2 42 37 37 31 -29 -25 32 2 -24 27 40 -26 4 39 -23 55 54 19 0 0 -24 44 32 2 42 44 38 30 -29 -25 16 48 -24 12 33 -25 49 20 -23 40 50 20 0 0 -24 29 47 2 42 50 39 29 -28 -25 1 59 -23 57 52 -25 34 28 -23 26 13 21 0 0 -24 15 28 2 42 56 39 28 -27 -24 47 36 -23 43 37 -25 20 2 -23 12 1 22 0 0 -24 1 36 2 43 3 40 27 -26 -24 33 40 -23 29 48 -25 6 2 -22 58 16 23 0 0 -23 48 11 2 43 9 41 26 -25 -24 20 12 -23 16 26 -24 52 30 -22 44 57 24 0 0 -23 35 13 2 43 16 41 25 -24 -24 7 10 -23 3 31 -24 39 25 -22 32 5 25 0 0 -23 22 42 2 43 22 42 24 -23 -23 54 36 -22 51 4 -24 26 47 -22 19 41 26 0 0 -23 10 39 2 43 29 42 23 -22 -23 42 30 -22 39 4 -24 14 38 -22 7 44 27 0 0 -22 59 4 2 43 36 43 22 -21 -23 30 53 -22 27 32 -24 2 57 -21 56 16 28 0 0 -22 47 58 2 43 43 43 21 -20 -23 19 43 -22 16 29 -23 51 45 -21 45 15 29 0 0 -22 37 20 2 43 50 44 19 -19 -23 9 2 -22 5 54 -23 41 1 -21 34 42 30 0 0 -22 27 11 2 43 57 44 18 -18 -22 58 50 -21 55 47 -23 30 46 -21 24 39 31 0 0 -22 17 31 2 44 4 45 17 -18 -22 49 8 -21 46 9 -23 21 1 -21 15 3 32 0 0 -22 8 20 2 44 11 45 16 -17 -22 39 54 -21 37 1 -23 11 45 -21 5 57 33 0 0 -21 59 38 2 44 18 46 14 -16 -22 31 10 -21 28 22 -23 2 59 -20 57 20 34 0 0 -21 51 26 2 44 25 46 13 -15 -22 22 56 -21 20 12 -22 54 42 -20 49 12 35 0 0 -21 43 44 2 44 33 46 12 -14 -22 15 12 -21 12 32 -22 46 56 -20 41 34 36 0 0 -21 36 31 2 44 40 47 10 -13 -22 7 57 -21 5 21 -22 39 39 -20 34 26 37 0 0 -21 29 49 2 44 47 47 9 -12 -22 1 13 -20 58 40 -22 32 53 -20 27 47 38 0 0 -21 23 37 2 44 55 47 8 -11 -21 54 59 -20 52 30 -22 26 37 -20 21 38 39 0 0 -21 17 55 2 45 2 47 6 -10 -21 49 15 -20 46 49 -22 20 52 -20 15 59 40 0 0 -21 12 43 2 45 9 48 5 -9 -21 44 2 -20 41 39 -22 15 37 -20 10 50 41 0 0 -21 8 2 2 45 17 48 4 -8 -21 39 20 -20 36 59 -22 10 54 -20 6 11 42 0 0 -21 3 51 2 45 24 48 2 -7 -21 35 8 -20 32 50 -22 6 41 -20 2 3 43 0 0 -21 0 11 2 45 32 48 1 -6 -21 31 27 -20 29 11 -22 2 59 -19 58 25 44 0 0 -20 57 2 2 45 39 48 359 -5 -21 28 17 -20 26 2 -21 59 47 -19 55 17 45 0 0 -20 54 23 2 45 47 48 358 -4 -21 25 37 -20 23 25 -21 57 7 -19 52 40 46 0 0 -20 52 16 2 45 54 48 356 -3 -21 23 29 -20 21 17 -21 54 58 -19 50 34 47 0 0 -20 50 39 2 46 2 48 355 -2 -21 21 52 -20 19 41 -21 53 20 -19 48 58 48 0 0 -20 49 33 2 46 9 48 353 -1 -21 20 45 -20 18 35 -21 52 14 -19 47 52 49 0 0 -20 48 57 2 46 17 48 352 0 -21 20 10 -20 18 0 -21 51 38 -19 47 17 Uncertainty in time = +/- 5 secs Prediction of 2012 Jul 21.0 Data for the target star ------------------------ * name: TYC 1293-00686-1 * constellation : Taurus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 05 00 44.3097 DE: +21 13 26.025 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .025, .017 ) * V mag [mag]: 9.0 * B mag [mag]: 10.2 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (122) Gerda approx. diameter [km]: 85 approx. diameter ["]: .039 distance from Earth [AU]: 3.00600 * orbital information: orbit source: Preston date of fit: 2012 Jul 21 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1310 number of rejected observations: 113 time covered by the observations: 1901 Aug 09 - 2012 Jan 19 1 sigma uncertainty ellipse (major, minor, PA): 0.017, 0.010, 84° remarks: * orbital elements for (122) Gerda : Mean anomaly = 282.76604882 deg Arg. of pericenter = 320.92446504 deg Long. of node = 178.37032347 deg Inclination = 1.63908613 deg Eccentricity = 0.03647470 Semimajor axis = 3.23089250 AU Perihelion dist = 3.11304668 AU Mag: H = 7.62, G = 0.15 Epoch of elements : MJD 56181.11500000 TDT (2012 Sep 11.115) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 11 122 Gerda 2h 45.8m UT 9.0 5 0 44.310 21 13 26.02TYC 1293-00686-1 10.2 13.7 85 5.9 3.006 1.695 0.96 43.2127 21.223 137.71 4.44 2.7627 0.02366 -0.66907 8.10289 0.32841 -0.00574 -0.00058 2000 282.5768172012 910.00000320.924465178.370323 1.6390860.03647470 3.2308925 3.1130467 7.9 5.00.15 RATE 1.6971500 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.030 0.019 88 1.50 0.019 0 0-3 5 056129.0020120911_0686-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 21, 15:33 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org