IOTA/IOTA-ES occultation update for (972) Cohnia / TYC 1875-02202-1 event on 2012 Sep 08, 00:58 UT Visible from SW Asia, Africa Summary ------- On 2012 Sep 08 UT, the 80 km diameter asteroid (972) Cohnia will occult a 11.2 mag star in the constellation Taurus for observers along a path across SW Asia, Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 3.4 mag to 14.6 mag (the magnitude of the asteroid) for at most 3.4 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 08, 00:54 - 2012 Sep 08, 00:57 UT * geocentric midpoint of event [JD]: 2456178.54057083 * magnitude of target star: 11.2 * magnitude drop [mag]: 3.4 * estimated maximum duration [s]: 3.4 * Moon: 55 % sunlit, 19° distance * Sun: 77° distance * rough path description: SW Asia, Africa The occultation path -------------------- * approximate projected width [km]: 83 * 1 sigma uncertainty interval [path widths]: +/- 0.49 * 1 sigma uncertainty interval [seconds]: +/- 2.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .029 +/- .021) * 1 sigma uncertainty ellipse (major, minor, PA): ( .029", .021", 95° ) * approx speed of asteroid's shadow [km/s]: 23.5511 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 1875-02202-1 by 972 Cohnia on 2012 Sep 8 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 - 9 0 0 13 36 39 0 54 4 0 61 -70 13 10 59 14 2 23 .. .. .. 14 27 39 - 8 0 0 14 9 24 0 54 4 1 61 -69 13 43 43 14 35 8 13 18 36 15 0 25 - 7 0 0 14 42 7 0 54 5 3 61 -69 14 16 26 15 7 52 13 51 18 15 33 9 - 6 0 0 15 14 49 0 54 5 4 62 -68 14 49 7 15 40 34 14 23 59 16 5 52 - 5 0 0 15 47 28 0 54 5 5 62 -67 15 21 46 16 13 14 14 56 37 16 38 32 - 4 0 0 16 20 3 0 54 6 6 62 -66 15 54 21 16 45 49 15 29 13 17 11 7 - 3 0 0 16 52 34 0 54 6 7 63 -65 16 26 52 17 18 20 16 1 43 17 43 38 - 2 0 0 17 24 59 0 54 7 8 63 -64 16 59 17 17 50 45 16 34 9 18 16 3 - 1 0 0 17 57 18 0 54 8 9 63 -63 17 31 36 18 23 3 17 6 28 18 48 21 0 0 0 18 29 29 0 54 9 10 63 -62 18 3 47 18 55 14 17 38 40 19 20 31 1 0 0 19 1 31 0 54 10 11 64 -61 18 35 50 19 27 16 18 10 44 19 52 32 2 0 0 19 33 25 0 54 11 12 64 -60 19 7 45 19 59 8 18 42 38 20 24 24 3 0 0 20 5 8 0 54 12 14 64 -59 19 39 29 20 30 50 19 14 23 20 56 5 4 0 0 20 36 40 0 54 13 15 65 -58 20 11 2 21 2 21 19 45 57 21 27 35 5 0 0 21 8 0 0 54 15 16 65 -57 20 42 23 21 33 40 20 17 20 21 58 53 6 0 0 21 39 7 0 54 16 17 66 -56 21 13 32 22 4 46 20 48 30 22 29 57 7 0 0 22 10 1 0 54 18 18 66 -55 21 44 27 22 35 38 21 19 27 23 0 48 8 0 0 22 40 40 0 54 19 19 66 -54 22 15 8 23 6 16 21 50 9 23 31 24 9 0 0 23 11 4 0 54 21 20 67 -53 22 45 34 23 36 38 22 20 37 24 1 45 10 0 0 23 41 12 0 54 23 21 67 -52 23 15 44 24 6 44 22 50 49 24 31 49 11 0 0 24 11 4 0 54 25 22 68 -51 23 45 37 24 36 34 23 20 44 25 1 36 12 0 0 24 40 38 0 54 27 23 68 -50 24 15 14 25 6 6 23 50 23 25 31 6 13 0 0 25 9 55 0 54 29 24 69 -50 24 44 33 25 35 20 24 19 44 26 0 18 14 0 0 25 38 52 0 54 31 25 69 -49 25 13 33 26 4 15 24 48 46 26 29 11 15 0 0 26 7 31 0 54 33 26 70 -48 25 42 14 26 32 51 25 17 30 26 57 44 16 0 0 26 35 50 0 54 35 27 70 -47 26 10 35 27 1 7 25 45 54 27 25 58 17 0 0 27 3 48 0 54 38 28 71 -46 26 38 36 27 29 3 26 13 58 27 53 51 18 0 0 27 31 25 0 54 40 29 71 -45 27 6 16 27 56 37 26 41 41 28 21 22 19 0 0 27 58 42 0 54 42 30 72 -44 27 33 36 28 23 51 27 9 3 28 48 33 20 0 0 28 25 36 0 54 45 31 72 -43 28 0 33 28 50 42 27 36 3 29 15 21 21 0 0 28 52 8 0 54 47 32 73 -42 28 27 8 29 17 11 28 2 41 29 41 47 22 0 0 29 18 17 0 54 50 33 74 -41 28 53 20 29 43 17 28 28 57 30 7 49 23 0 0 29 44 3 0 54 53 34 74 -40 29 19 10 30 9 0 28 54 49 30 33 29 24 0 0 30 9 26 0 54 55 35 75 -39 29 44 36 30 34 19 29 20 18 30 58 45 25 0 0 30 34 25 0 54 58 36 75 -38 30 9 38 30 59 15 29 45 24 31 23 37 26 0 0 30 59 0 0 55 1 37 76 -37 30 34 17 31 23 46 30 10 6 31 48 6 27 0 0 31 23 10 0 55 4 38 77 -36 30 58 31 31 47 53 30 34 23 32 12 9 28 0 0 31 46 56 0 55 7 39 77 -35 31 22 20 32 11 36 30 58 16 32 35 48 29 0 0 32 10 18 0 55 9 40 78 -34 31 45 45 32 34 53 31 21 44 32 59 2 30 0 0 32 33 14 0 55 12 41 79 -33 32 8 45 32 57 45 31 44 48 33 21 51 31 0 0 32 55 44 0 55 15 41 79 -32 32 31 19 33 20 13 32 7 26 33 44 14 32 0 0 33 17 50 0 55 18 42 80 -31 32 53 28 33 42 14 32 29 38 34 6 13 33 0 0 33 39 30 0 55 21 43 81 -30 33 15 12 34 3 51 32 51 25 34 27 45 34 0 0 34 0 44 0 55 25 44 82 -30 33 36 29 34 25 1 33 12 47 34 48 52 35 0 0 34 21 32 0 55 28 45 83 -29 33 57 22 34 45 46 33 33 42 35 9 33 36 0 0 34 41 55 0 55 31 46 83 -28 34 17 48 35 6 5 33 54 12 35 29 48 37 0 0 35 1 51 0 55 34 47 84 -27 34 37 48 35 25 57 34 14 16 35 49 37 38 0 0 35 21 22 0 55 37 48 85 -26 34 57 22 35 45 24 34 33 54 36 9 1 39 0 0 35 40 27 0 55 40 48 86 -25 35 16 30 36 4 25 34 53 6 36 27 58 40 0 0 35 59 5 0 55 44 49 87 -24 35 35 13 36 23 0 35 11 51 36 46 29 41 0 0 36 17 17 0 55 47 50 88 -23 35 53 29 36 41 9 35 30 11 37 4 34 42 0 0 36 35 4 0 55 50 51 89 -23 36 11 19 36 58 52 35 48 4 37 22 13 43 0 0 36 52 24 0 55 53 52 90 -22 36 28 42 37 16 8 36 5 32 37 39 27 44 0 0 37 9 18 0 55 57 53 91 -21 36 45 40 37 32 59 36 22 33 37 56 14 45 0 0 37 25 46 0 56 0 53 92 -20 37 2 12 37 49 24 36 39 8 38 12 35 46 0 0 37 41 49 0 56 3 54 93 -19 37 18 17 38 5 22 36 55 17 38 28 30 47 0 0 37 57 25 0 56 7 55 94 -18 37 33 57 38 20 55 37 11 0 38 44 0 48 0 0 38 12 35 0 56 10 56 95 -17 37 49 11 38 36 2 37 26 17 38 59 4 49 0 0 38 27 20 0 56 13 56 96 -17 38 3 59 38 50 44 37 41 8 39 13 42 50 0 0 38 41 39 0 56 17 57 97 -16 38 18 21 39 4 59 37 55 33 39 27 54 51 0 0 38 55 32 0 56 20 58 98 -15 38 32 17 39 18 49 38 9 33 39 41 41 52 0 0 39 9 0 0 56 24 59 99 -14 38 45 48 39 32 14 38 23 7 39 55 2 53 0 0 39 22 2 0 56 27 59 100 -13 38 58 53 39 45 13 38 36 15 40 7 59 54 0 0 39 34 39 0 56 30 60 102 -13 39 11 33 39 57 47 38 48 57 40 20 29 55 0 0 39 46 50 0 56 34 61 103 -12 39 23 47 40 9 55 39 1 15 40 32 35 56 0 0 39 58 36 0 56 37 62 104 -11 39 35 36 40 21 39 39 13 6 40 44 16 57 0 0 40 9 57 0 56 41 62 106 -10 39 47 0 40 32 57 39 24 33 40 55 31 58 0 0 40 20 53 0 56 44 63 107 -9 39 57 59 40 43 50 39 35 34 41 6 22 59 0 0 40 31 25 0 56 48 64 109 -9 40 8 33 40 54 19 39 46 10 41 16 48 60 0 0 40 41 31 0 56 51 64 110 -8 40 18 41 41 4 23 39 56 22 41 26 49 61 0 0 40 51 12 0 56 55 65 112 -7 40 28 25 41 14 2 40 6 8 41 36 26 62 0 0 41 0 29 0 56 58 66 113 -6 40 37 45 41 23 16 40 15 29 41 45 38 63 0 0 41 9 21 0 57 2 66 115 -5 40 46 39 41 32 6 40 24 26 41 54 26 64 0 0 41 17 49 0 57 5 67 117 -5 40 55 9 41 40 32 40 32 58 42 2 49 65 0 0 41 25 53 0 57 9 67 118 -4 41 3 15 41 48 33 40 41 6 42 10 48 66 0 0 41 33 32 0 57 12 68 120 -3 41 10 56 41 56 10 40 48 49 42 18 24 67 0 0 41 40 47 0 57 16 69 122 -2 41 18 13 42 3 23 40 56 7 42 25 35 68 0 0 41 47 38 0 57 19 69 124 -2 41 25 5 42 10 12 41 3 2 42 32 22 69 0 0 41 54 4 0 57 23 70 126 -1 41 31 34 42 16 37 41 9 32 42 38 46 70 0 0 42 0 7 0 57 26 70 129 0 41 37 38 42 22 39 41 15 38 42 44 45 Uncertainty in time = +/- 2 secs Prediction of 2012 Jul 21.0 Data for the target star ------------------------ * name: TYC 1875-02202-1 * constellation : Taurus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 05 55 23.7706 DE: +28 15 55.526 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .020, .020 ) * V mag [mag]: 11.2 * B mag [mag]: 11.6 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (972) Cohnia approx. diameter [km]: 80 approx. diameter ["]: .043 distance from Earth [AU]: 2.54500 * orbital information: orbit source: Preston date of fit: 2012 Jul 21 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1091 number of rejected observations: 59 time covered by the observations: 1906 Jan 22 - 2012 Jan 03 1 sigma uncertainty ellipse (major, minor, PA): 0.021, 0.008, 100° remarks: * orbital elements for (972) Cohnia : Mean anomaly = 31.40210142 deg Arg. of pericenter = 94.44379463 deg Long. of node = 281.54319083 deg Inclination = 8.36476638 deg Eccentricity = 0.23434938 Semimajor axis = 3.06129370 AU Perihelion dist = 2.34388143 AU Mag: H = 9.54, G = 0.15 Epoch of elements : MJD 56178.04100000 TDT (2012 Sep 08.041) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 8 972 Cohnia 0h 58.4m UT 11.2 5 55 23.771 28 15 55.53TYC 1875-02202-1 11.6 14.6 80 3.4 2.545 3.475 -0.79 86.7419 28.266 164.82 5.60 0.9737 -0.00121 0.24589 13.29099 -0.22648 -0.00539 0.00007 2000 29.9224592012 831.00000 94.443795281.543191 8.3647660.23434938 3.0612937 2.3438814 9.5 5.00.15 RATE 1.8401220 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.029 0.021 95 1.49 0.021 0 0-4-4 056129.0020120908_2202-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 21, 15:20 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org