IOTA/IOTA-ES occultation update for (34) Circe / UCAC2 37530440 event on 2012 Sep 25, 21:38 UT Visible from China, SW Asia Summary ------- On 2012 Sep 25 UT, the 117 km diameter asteroid (34) Circe will occult a 11.8 mag star in the constellation Gemini for observers along a path across China, SW Asia. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.1 mag to 13.8 mag (the magnitude of the asteroid) for at most 4.0 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: UCAC. The event at a glimpse ---------------------- * Rank: 51 * date and approx. time of event: 2012 Sep 25, 21:35 - 2012 Sep 25, 21:37 UT * geocentric midpoint of event [JD]: 2456196.40192917 * magnitude of target star: 11.8 * magnitude drop [mag]: 2.1 * estimated maximum duration [s]: 4.0 * Moon: 81 % sunlit, 164° distance * Sun: 68° distance * rough path description: China, SW Asia The occultation path -------------------- * approximate projected width [km]: 119 * 1 sigma uncertainty interval [path widths]: +/- 1.25 * 1 sigma uncertainty interval [seconds]: +/- 4.9 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .075 +/- .074) * 1 sigma uncertainty ellipse (major, minor, PA): ( .075", .074", 90° ) * approx speed of asteroid's shadow [km/s]: 29.4575 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC2 37530440 by 34 Circe on 2012 Sep 25 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 51 0 0 23 47 22 21 35 15 0 73 -62 23 13 32 24 21 15 .. .. .. 25 46 17 52 0 0 24 4 34 21 35 15 1 73 -61 23 30 47 24 38 25 22 6 36 26 3 20 53 0 0 24 21 30 21 35 15 2 73 -61 23 47 46 24 55 18 22 23 41 26 20 7 54 0 0 24 38 9 21 35 15 3 74 -60 24 4 28 25 11 55 22 40 29 26 36 38 55 0 0 24 54 32 21 35 15 4 74 -59 24 20 53 25 28 15 22 57 1 26 52 52 56 0 0 25 10 38 21 35 15 5 75 -58 24 37 2 25 44 19 23 13 16 27 8 49 57 0 0 25 26 27 21 35 16 6 75 -57 24 52 53 26 0 5 23 29 14 27 24 29 58 0 0 25 41 59 21 35 16 7 76 -56 25 8 28 26 15 35 23 44 54 27 39 51 59 0 0 25 57 14 21 35 17 8 76 -56 25 23 45 26 30 46 24 0 18 27 54 56 60 0 0 26 12 10 21 35 17 9 76 -55 25 38 44 26 45 41 24 15 23 28 9 44 61 0 0 26 26 49 21 35 18 10 77 -54 25 53 26 27 0 17 24 30 11 28 24 14 62 0 0 26 41 10 21 35 18 11 77 -53 26 7 49 27 14 35 24 44 41 28 38 26 63 0 0 26 55 14 21 35 19 12 78 -52 26 21 55 27 28 36 24 58 53 28 52 20 64 0 0 27 8 58 21 35 20 13 78 -51 26 35 42 27 42 18 25 12 47 29 5 56 65 0 0 27 22 25 21 35 21 13 79 -51 26 49 11 27 55 42 25 26 22 29 19 13 66 0 0 27 35 33 21 35 21 14 79 -50 27 2 22 28 8 48 25 39 39 29 32 12 67 0 0 27 48 23 21 35 22 15 80 -49 27 15 14 28 21 35 25 52 37 29 44 53 68 0 0 28 0 53 21 35 23 16 80 -48 27 27 47 28 34 3 26 5 17 29 57 15 69 0 0 28 13 6 21 35 24 17 81 -47 27 40 2 28 46 13 26 17 38 30 9 19 70 0 0 28 24 59 21 35 25 18 81 -46 27 51 58 28 58 4 26 29 39 30 21 3 71 0 0 28 36 33 21 35 26 19 82 -45 28 3 34 29 9 36 26 41 22 30 32 29 72 0 0 28 47 49 21 35 28 20 82 -45 28 14 52 29 20 49 26 52 45 30 43 36 73 0 0 28 58 45 21 35 29 21 83 -44 28 25 51 29 31 43 27 3 50 30 54 24 74 0 0 29 9 22 21 35 30 22 83 -43 28 36 30 29 42 18 27 14 34 31 4 53 75 0 0 29 19 40 21 35 31 22 84 -42 28 46 50 29 52 33 27 25 0 31 15 3 76 0 0 29 29 38 21 35 33 23 84 -41 28 56 51 30 2 30 27 35 6 31 24 54 77 0 0 29 39 18 21 35 34 24 85 -40 29 6 32 30 12 7 27 44 53 31 34 26 78 0 0 29 48 37 21 35 36 25 85 -39 29 15 54 30 21 24 27 54 20 31 43 38 79 0 0 29 57 38 21 35 37 26 86 -39 29 24 56 30 30 23 28 3 27 31 52 32 80 0 0 30 6 19 21 35 39 27 86 -38 29 33 39 30 39 1 28 12 15 32 1 5 81 0 0 30 14 40 21 35 40 28 87 -37 29 42 2 30 47 21 28 20 43 32 9 20 82 0 0 30 22 42 21 35 42 29 87 -36 29 50 6 30 55 21 28 28 51 32 17 15 83 0 0 30 30 24 21 35 43 30 88 -35 29 57 50 31 3 1 28 36 39 32 24 51 84 0 0 30 37 46 21 35 45 30 89 -34 30 5 14 31 10 22 28 44 8 32 32 7 85 0 0 30 44 49 21 35 47 31 89 -33 30 12 19 31 17 23 28 51 16 32 39 4 86 0 0 30 51 32 21 35 49 32 90 -33 30 19 3 31 24 4 28 58 5 32 45 42 87 0 0 30 57 55 21 35 50 33 90 -32 30 25 28 31 30 26 29 4 34 32 51 59 88 0 0 31 3 59 21 35 52 34 91 -31 30 31 33 31 36 28 29 10 42 32 57 58 89 0 0 31 9 43 21 35 54 35 91 -30 30 37 18 31 42 11 29 16 31 33 3 37 90 0 0 31 15 7 21 35 56 36 92 -29 30 42 44 31 47 34 29 22 0 33 8 56 91 0 0 31 20 11 21 35 58 36 93 -28 30 47 49 31 52 37 29 27 8 33 13 56 92 0 0 31 24 56 21 36 0 37 93 -28 30 52 35 31 57 20 29 31 57 33 18 36 93 0 0 31 29 20 21 36 2 38 94 -27 30 57 1 32 1 43 29 36 25 33 22 57 94 0 0 31 33 25 21 36 4 39 95 -26 31 1 6 32 5 47 29 40 33 33 26 58 95 0 0 31 37 10 21 36 6 40 95 -25 31 4 52 32 9 31 29 44 22 33 30 40 96 0 0 31 40 35 21 36 8 41 96 -24 31 8 18 32 12 55 29 47 50 33 34 1 97 0 0 31 43 40 21 36 10 42 96 -23 31 11 24 32 15 59 29 50 57 33 37 4 98 0 0 31 46 25 21 36 13 42 97 -22 31 14 10 32 18 44 29 53 45 33 39 46 99 0 0 31 48 50 21 36 15 43 98 -22 31 16 36 32 21 8 29 56 12 33 42 10 100 0 0 31 50 56 21 36 17 44 98 -21 31 18 42 32 23 13 29 58 20 33 44 13 101 0 0 31 52 41 21 36 20 45 99 -20 31 20 27 32 24 58 30 0 7 33 45 57 102 0 0 31 54 7 21 36 22 46 100 -19 31 21 53 32 26 23 30 1 33 33 47 21 103 0 0 31 55 12 21 36 24 47 101 -18 31 22 59 32 27 29 30 2 40 33 48 25 104 0 0 31 55 58 21 36 27 47 101 -17 31 23 45 32 28 14 30 3 26 33 49 10 105 0 0 31 56 23 21 36 29 48 102 -17 31 24 11 32 28 39 30 3 52 33 49 35 106 0 0 31 56 29 21 36 32 49 103 -16 31 24 16 32 28 45 30 3 58 33 49 41 107 0 0 31 56 15 21 36 34 50 104 -15 31 24 2 32 28 31 30 3 44 33 49 27 108 0 0 31 55 40 21 36 37 51 104 -14 31 23 27 32 27 56 30 3 9 33 48 53 109 0 0 31 54 46 21 36 39 52 105 -13 31 22 33 32 27 2 30 2 14 33 47 59 110 0 0 31 53 32 21 36 42 52 106 -12 31 21 18 32 25 48 30 0 58 33 46 46 111 0 0 31 51 57 21 36 45 53 107 -11 31 19 43 32 24 14 29 59 23 33 45 13 112 0 0 31 50 3 21 36 47 54 108 -11 31 17 49 32 22 20 29 57 27 33 43 20 113 0 0 31 47 48 21 36 50 55 108 -10 31 15 34 32 20 6 29 55 10 33 41 7 114 0 0 31 45 14 21 36 53 56 109 -9 31 12 59 32 17 33 29 52 34 33 38 35 115 0 0 31 42 19 21 36 55 57 110 -8 31 10 3 32 14 39 29 49 37 33 35 43 116 0 0 31 39 5 21 36 58 57 111 -7 31 6 48 32 11 25 29 46 19 33 32 31 117 0 0 31 35 30 21 37 1 58 112 -6 31 3 13 32 7 51 29 42 42 33 29 0 118 0 0 31 31 36 21 37 4 59 113 -5 30 59 17 32 3 58 29 38 44 33 25 9 119 0 0 31 27 21 21 37 7 60 114 -5 30 55 1 31 59 44 29 34 26 33 20 57 120 0 0 31 22 46 21 37 10 61 115 -4 30 50 25 31 55 10 29 29 47 33 16 27 121 0 0 31 17 51 21 37 13 62 116 -3 30 45 29 31 50 17 29 24 48 33 11 36 122 0 0 31 12 36 21 37 15 62 117 -2 30 40 13 31 45 3 29 19 29 33 6 26 123 0 0 31 7 1 21 37 18 63 118 -1 30 34 37 31 39 29 29 13 49 33 0 55 124 0 0 31 1 6 21 37 21 64 120 0 30 28 40 31 33 36 29 7 49 32 55 5 Uncertainty in time = +/- 5 secs Prediction of 2012 Aug 7.0 Data for the target star ------------------------ * name: UCAC2 37530440 * constellation : Gemini * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 07 46 22.1998 DE: +16 01 39.112 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .074, .074 ) * V mag [mag]: 11.8 * B mag [mag]: 0.0 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (34) Circe approx. diameter [km]: 117 approx. diameter ["]: .059 distance from Earth [AU]: 2.73600 * orbital information: orbit source: Preston date of fit: 2012 Aug 06 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1510 number of rejected observations: 142 time covered by the observations: 1914 Sep 26 - 2012 Jan 21 1 sigma uncertainty ellipse (major, minor, PA): 0.014, 0.006, 98° remarks: * orbital elements for (34) Circe : Mean anomaly = 309.59082707 deg Arg. of pericenter = 330.00105886 deg Long. of node = 184.45398334 deg Inclination = 5.49795633 deg Eccentricity = 0.10477965 Semimajor axis = 2.68808459 AU Perihelion dist = 2.40642803 AU Mag: H = 8.49, G = 0.15 Epoch of elements : MJD 56195.90200000 TDT (2012 Sep 25.902) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 25 34 Circe 21h 38.8m UT 11.8 7 46 22.200 16 1 39.11UCAC2 37530440 0.0 13.8 117 4.0 2.736 3.600 -12.77 146.7911 16.031 -146.84 -1.28 21.6463 0.04240 0.18145 16.14521 -3.97208 -0.00513 0.00074 2000 308.2709342012 920.00000330.001059184.453983 5.4979560.10477965 2.6880846 2.4064280 8.5 5.00.15 RATE 2.2363490 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.075 0.074 90 2.25 0.074 0 0-2 2 056146.0020120925_530440 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Aug 06, 21:03 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org