IOTA/IOTA-ES occultation update for (34) Circe / 2UCAC 37883348 event on 2012 Sep 13, 09:28 UT Visible from Canada, USA Summary ------- On 2012 Sep 13 UT, the 117 km diameter asteroid (34) Circe will occult a 12.8 mag star in the constellation Gemini for observers along a path across Canada, USA. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.4 mag to 13.8 mag (the magnitude of the asteroid) for at most 3.5 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: 26 * date and approx. time of event: 2012 Sep 13, 09:25 - 2012 Sep 13, 09:27 UT * geocentric midpoint of event [JD]: 2456183.89500417 * magnitude of target star: 12.8 * magnitude drop [mag]: 1.4 * estimated maximum duration [s]: 3.5 * Moon: 9 % sunlit, 26° distance * Sun: 60° distance * rough path description: Canada, USA Additional comments ------------------- double star The occultation path -------------------- * approximate projected width [km]: 127 * 1 sigma uncertainty interval [path widths]: +/- 2.59 * 1 sigma uncertainty interval [seconds]: +/- 12.6 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .209 +/- .142) * 1 sigma uncertainty ellipse (major, minor, PA): ( .209", .142", 90° ) * approx speed of asteroid's shadow [km/s]: 33.0716 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 37883348 by 34 Circe on 2012 Sep 13 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 -123 0 0 33 34 27 9 25 52 1 70 -49 32 57 39 34 11 25 .. .. .. 37 26 10 -122 0 0 33 52 59 9 25 52 2 70 -48 33 16 13 34 29 55 .. .. .. 37 44 26 -121 0 0 34 11 17 9 25 52 2 71 -47 33 34 34 34 48 11 .. .. .. 38 2 28 -120 0 0 34 29 21 9 25 52 3 72 -47 33 52 41 35 6 12 .. .. .. 38 20 15 -119 0 0 34 47 11 9 25 52 4 72 -46 34 10 33 35 23 59 .. .. .. 38 37 47 -118 0 0 35 4 45 9 25 53 5 73 -45 34 28 10 35 41 31 .. .. .. 38 55 4 -117 0 0 35 22 5 9 25 53 6 73 -44 34 45 33 35 58 48 .. .. .. 39 12 6 -116 0 0 35 39 10 9 25 53 7 74 -44 35 2 40 36 15 50 .. .. .. 39 28 52 -115 0 0 35 55 59 9 25 54 8 75 -43 35 19 32 36 32 36 .. .. .. 39 45 22 -114 0 0 36 12 33 9 25 54 8 75 -42 35 36 9 36 49 7 .. .. .. 40 1 37 -113 0 0 36 28 50 9 25 55 9 76 -41 35 52 30 37 5 22 .. .. .. 40 17 36 -112 0 0 36 44 52 9 25 55 10 76 -41 36 8 35 37 21 21 33 3 6 40 33 18 -111 0 0 37 0 38 9 25 56 11 77 -40 36 24 23 37 37 3 33 19 10 40 48 45 -110 0 0 37 16 8 9 25 56 12 78 -39 36 39 56 37 52 30 33 34 58 41 3 54 -109 0 0 37 31 21 9 25 57 13 78 -39 36 55 12 38 7 40 33 50 29 41 18 48 -108 0 0 37 46 18 9 25 58 13 79 -38 37 10 12 38 22 34 34 5 44 41 33 25 -107 0 0 38 0 58 9 25 58 14 79 -37 37 24 55 38 37 10 34 20 42 41 47 45 -106 0 0 38 15 21 9 25 59 15 80 -36 37 39 21 38 51 30 34 35 23 42 1 48 -105 0 0 38 29 27 9 26 0 16 81 -36 37 53 31 39 5 34 34 49 48 42 15 34 -104 0 0 38 43 16 9 26 1 17 81 -35 38 7 23 39 19 20 35 3 56 42 29 3 -103 0 0 38 56 49 9 26 2 18 82 -34 38 20 58 39 32 49 35 17 46 42 42 15 -102 0 0 39 10 4 9 26 3 18 83 -33 38 34 16 39 46 1 35 31 20 42 55 11 -101 0 0 39 23 2 9 26 4 19 83 -33 38 47 17 39 58 56 35 44 36 43 7 48 -100 0 0 39 35 42 9 26 5 20 84 -32 39 0 1 40 11 33 35 57 35 43 20 9 - 99 0 0 39 48 5 9 26 6 21 85 -31 39 12 27 40 23 53 36 10 16 43 32 13 - 98 0 0 40 0 11 9 26 7 22 85 -30 39 24 36 40 35 56 36 22 40 43 43 59 - 97 0 0 40 12 0 9 26 8 22 86 -30 39 36 27 40 47 42 36 34 46 43 55 28 - 96 0 0 40 23 30 9 26 9 23 87 -29 39 48 1 40 59 9 36 46 34 44 6 40 - 95 0 0 40 34 44 9 26 10 24 88 -28 39 59 17 41 10 20 36 58 5 44 17 34 - 94 0 0 40 45 39 9 26 11 25 88 -27 40 10 16 41 21 12 37 9 18 44 28 11 - 93 0 0 40 56 17 9 26 12 25 89 -27 40 20 57 41 31 48 37 20 13 44 38 30 - 92 0 0 41 6 38 9 26 14 26 90 -26 40 31 20 41 42 5 37 30 50 44 48 33 - 91 0 0 41 16 40 9 26 15 27 90 -25 40 41 25 41 52 5 37 41 9 44 58 17 - 90 0 0 41 26 25 9 26 16 28 91 -24 40 51 13 42 1 47 37 51 10 45 7 45 - 89 0 0 41 35 53 9 26 18 28 92 -24 41 0 43 42 11 12 38 0 53 45 16 55 - 88 0 0 41 45 2 9 26 19 29 93 -23 41 9 55 42 20 19 38 10 18 45 25 47 - 87 0 0 41 53 54 9 26 20 30 94 -22 41 18 50 42 29 8 38 19 26 45 34 23 - 86 0 0 42 2 28 9 26 22 31 94 -22 41 27 26 42 37 40 38 28 15 45 42 41 - 85 0 0 42 10 45 9 26 23 31 95 -21 41 35 45 42 45 54 38 36 46 45 50 41 - 84 0 0 42 18 44 9 26 25 32 96 -20 41 43 46 42 53 50 38 44 58 45 58 25 - 83 0 0 42 26 24 9 26 26 33 97 -19 41 51 29 43 1 29 38 52 53 46 5 51 - 82 0 0 42 33 48 9 26 28 34 98 -19 41 58 55 43 8 50 39 0 30 46 13 0 - 81 0 0 42 40 53 9 26 29 34 98 -18 42 6 3 43 15 53 39 7 48 46 19 51 - 80 0 0 42 47 41 9 26 31 35 99 -17 42 12 53 43 22 39 39 14 49 46 26 25 - 79 0 0 42 54 11 9 26 32 36 100 -16 42 19 25 43 29 7 39 21 31 46 32 42 - 78 0 0 43 0 24 9 26 34 36 101 -16 42 25 39 43 35 17 39 27 55 46 38 42 - 77 0 0 43 6 18 9 26 36 37 102 -15 42 31 36 43 41 10 39 34 1 46 44 25 - 76 0 0 43 11 55 9 26 37 38 103 -14 42 37 14 43 46 45 39 39 48 46 49 50 - 75 0 0 43 17 15 9 26 39 38 103 -14 42 42 35 43 52 3 39 45 18 46 54 59 - 74 0 0 43 22 16 9 26 41 39 104 -13 42 47 39 43 57 3 39 50 29 46 59 50 - 73 0 0 43 27 0 9 26 42 40 105 -12 42 52 24 44 1 46 39 55 22 47 4 24 - 72 0 0 43 31 27 9 26 44 41 106 -11 42 56 52 44 6 10 39 59 57 47 8 41 - 71 0 0 43 35 36 9 26 46 41 107 -11 43 1 2 44 10 18 40 4 14 47 12 41 - 70 0 0 43 39 27 9 26 48 42 108 -10 43 4 55 44 14 8 40 8 13 47 16 24 - 69 0 0 43 43 0 9 26 49 43 109 -9 43 8 29 44 17 40 40 11 54 47 19 50 - 68 0 0 43 46 16 9 26 51 43 110 -8 43 11 46 44 20 55 40 15 16 47 22 59 - 67 0 0 43 49 15 9 26 53 44 111 -8 43 14 46 44 23 52 40 18 20 47 25 51 - 66 0 0 43 51 55 9 26 55 45 112 -7 43 17 27 44 26 32 40 21 7 47 28 25 - 65 0 0 43 54 18 9 26 57 45 113 -6 43 19 51 44 28 54 40 23 35 47 30 43 - 64 0 0 43 56 24 9 26 59 46 114 -6 43 21 58 44 30 59 40 25 44 47 32 44 - 63 0 0 43 58 12 9 27 1 47 115 -5 43 23 46 44 32 47 40 27 36 47 34 28 - 62 0 0 43 59 43 9 27 3 47 116 -4 43 25 17 44 34 17 40 29 10 47 35 55 - 61 0 0 44 0 55 9 27 5 48 117 -3 43 26 31 44 35 29 40 30 25 47 37 5 - 60 0 0 44 1 51 9 27 7 48 118 -3 43 27 26 44 36 24 40 31 23 47 37 59 - 59 0 0 44 2 28 9 27 9 49 119 -2 43 28 4 44 37 2 40 32 2 47 38 35 - 58 0 0 44 2 49 9 27 11 50 121 -1 43 28 25 44 37 22 40 32 23 47 38 54 - 57 0 0 44 2 51 9 27 13 50 122 -1 43 28 27 44 37 24 40 32 26 47 38 56 Uncertainty in time = +/- 13 secs Prediction of 2012 Jul 21.0 Data for the target star ------------------------ * name: 2UCAC 37883348 * constellation : Gemini * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 07 27 37.9101 DE: +17 02 09.808 * position source: mpos:UCAC4 pm:UCAC4 * standard error: RA,DE ["]: ( .209, .142 ) * V mag [mag]: 12.8 * B mag [mag]: 0.0 * Apparent position with proper motion RA(deg): 112.0922417920 DE(deg): 17.0087092356 * Equation of equinoxes (radians) : 0.000068497896127 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (34) Circe approx. diameter [km]: 117 approx. diameter ["]: .056 distance from Earth [AU]: 2.89000 * orbital information: orbit source: Preston date of fit: 2012 Jul 21 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): 0.013, 0.006, 97° remarks: * orbital elements for (34) Circe : Mean anomaly = 306.81186374 deg Arg. of pericenter = 329.98225268 deg Long. of node = 184.45577194 deg Inclination = 5.49796244 deg Eccentricity = 0.10480880 Semimajor axis = 2.68820669 AU Perihelion dist = 2.40645897 AU Mag: H = 8.49, G = 0.15 Epoch of elements : MJD 56183.39500000 TDT (2012 Sep 13.395) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 13 34 Circe 9h 28.8m UT 12.8 7 27 37.910 17 2 9.812UCAC 37883348 0.0 13.8 117 3.5 2.890 3.881 -11.35 -23.0726 17.040 36.75 3.57 9.4801 0.07804 0.38890 18.29054 -3.72772 -0.00482 0.00049 2000 306.0526752012 910.00000329.982253184.455772 5.4979620.10480880 2.6882067 2.4064590 8.5 5.00.15 RATE 2.2361970 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.209 0.142 90 3.59 0.145 0 0 1-2 056129.0020120913_883348 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 22, 03:43 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org