IOTA/IOTA-ES occultation update for (972) Cohnia / 2UCAC 41675180 event on 2012 Aug 24, 03:00 UT Visible from Europe, W Africa Summary ------- On 2012 Aug 24 UT, the 80 km diameter asteroid (972) Cohnia will occult a 12.8 mag star in the constellation Taurus for observers along a path across Europe, W Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.1 mag to 14.7 mag (the magnitude of the asteroid) for at most 2.8 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: 64 * date and approx. time of event: 2012 Aug 24, 02:59 - 2012 Aug 24, 03:01 UT * geocentric midpoint of event [JD]: 2456163.62676667 * magnitude of target star: 12.8 * magnitude drop [mag]: 2.1 * estimated maximum duration [s]: 2.8 * Moon: 45 % sunlit, 151° distance * Sun: 67° distance * rough path description: Europe, W Africa The occultation path -------------------- * approximate projected width [km]: 87 * 1 sigma uncertainty interval [path widths]: +/- 0.95 * 1 sigma uncertainty interval [seconds]: +/- 2.3 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .039 +/- .039) * 1 sigma uncertainty ellipse (major, minor, PA): ( .039", .039", 92° ) * approx speed of asteroid's shadow [km/s]: 28.6789 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 41675180 by 972 Cohnia on 2012 Aug 24 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 - 34 0 0 19 18 22 2 59 8 1 60 -58 18 51 4 19 45 46 .. .. .. 20 38 9 - 33 0 0 19 51 28 2 59 8 2 61 -57 19 24 7 20 18 54 .. .. .. 21 11 21 - 32 0 0 20 24 37 2 59 8 3 61 -56 19 57 15 20 52 5 19 5 32 21 44 37 - 31 0 0 20 57 49 2 59 9 4 61 -56 20 30 25 21 25 20 19 38 38 22 17 55 - 30 0 0 21 31 3 2 59 9 5 62 -55 21 3 37 21 58 35 20 11 47 22 51 14 - 29 0 0 22 4 17 2 59 10 6 62 -54 21 36 50 22 31 51 20 44 57 23 24 33 - 28 0 0 22 37 32 2 59 10 7 62 -53 22 10 3 23 5 7 21 18 7 23 57 52 - 27 0 0 23 10 44 2 59 11 8 63 -52 22 43 14 23 38 21 21 51 16 24 31 8 - 26 0 0 23 43 55 2 59 11 9 63 -51 23 16 24 24 11 33 22 24 24 25 4 22 - 25 0 0 24 17 2 2 59 12 10 64 -50 23 49 30 24 44 41 22 57 28 25 37 31 - 24 0 0 24 50 4 2 59 13 12 64 -49 24 22 31 25 17 44 23 30 28 26 10 36 - 23 0 0 25 23 1 2 59 14 13 64 -48 24 55 28 25 50 41 24 3 24 26 43 34 - 22 0 0 25 55 52 2 59 15 14 65 -47 25 28 18 26 23 32 24 36 13 27 16 26 - 21 0 0 26 28 34 2 59 16 15 65 -46 26 1 0 26 56 15 25 8 55 27 49 9 - 20 0 0 27 1 9 2 59 17 16 66 -45 26 33 35 27 28 49 25 41 30 28 21 43 - 19 0 0 27 33 33 2 59 18 17 66 -44 27 6 0 28 1 14 26 13 55 28 54 7 - 18 0 0 28 5 47 2 59 20 18 67 -43 27 38 14 28 33 27 26 46 11 29 26 20 - 17 0 0 28 37 50 2 59 21 19 67 -43 28 10 18 29 5 30 27 18 15 29 58 21 - 16 0 0 29 9 41 2 59 23 20 68 -42 28 42 9 29 37 19 27 50 8 30 30 9 - 15 0 0 29 41 18 2 59 24 21 69 -41 29 13 47 30 8 56 28 21 49 31 1 43 - 14 0 0 30 12 42 2 59 26 22 69 -40 29 45 12 30 40 18 28 53 15 31 33 3 - 13 0 0 30 43 50 2 59 27 23 70 -39 30 16 22 31 11 25 29 24 28 32 4 7 - 12 0 0 31 14 43 2 59 29 24 70 -38 30 47 16 31 42 16 29 55 25 32 34 55 - 11 0 0 31 45 19 2 59 31 25 71 -37 31 17 54 32 12 50 30 26 6 33 5 27 - 10 0 0 32 15 38 2 59 33 26 72 -36 31 48 15 32 43 8 30 56 31 33 35 40 - 9 0 0 32 45 39 2 59 34 27 72 -35 32 18 19 33 13 7 31 26 38 34 5 35 - 8 0 0 33 15 22 2 59 36 28 73 -34 32 48 3 33 42 47 31 56 27 34 35 11 - 7 0 0 33 44 45 2 59 38 29 73 -33 33 17 29 34 12 8 32 25 57 35 4 27 - 6 0 0 34 13 49 2 59 40 30 74 -32 33 46 35 34 41 9 32 55 8 35 33 23 - 5 0 0 34 42 32 2 59 42 30 75 -31 34 15 21 35 9 49 33 23 59 36 1 58 - 4 0 0 35 10 54 2 59 44 31 76 -30 34 43 46 35 38 8 33 52 29 36 30 11 - 3 0 0 35 38 54 2 59 46 32 76 -29 35 11 49 36 6 6 34 20 39 36 58 3 - 2 0 0 36 6 33 2 59 49 33 77 -28 35 39 31 36 33 41 34 48 26 37 25 32 - 1 0 0 36 33 49 2 59 51 34 78 -27 36 6 50 37 0 54 35 15 52 37 52 38 0 0 0 37 0 42 2 59 53 35 79 -27 36 33 47 37 27 43 35 42 54 38 19 21 1 0 0 37 27 12 2 59 55 36 79 -26 37 0 20 37 54 10 36 9 34 38 45 41 2 0 0 37 53 18 2 59 57 37 80 -25 37 26 30 38 20 12 36 35 51 39 11 36 3 0 0 38 19 0 3 0 0 38 81 -24 37 52 16 38 45 51 37 1 44 39 37 7 4 0 0 38 44 18 3 0 2 38 82 -23 38 17 38 39 11 5 37 27 13 40 2 14 5 0 0 39 9 12 3 0 4 39 83 -22 38 42 35 39 35 54 37 52 17 40 26 56 6 0 0 39 33 41 3 0 7 40 84 -21 39 7 8 40 0 19 38 16 57 40 51 13 7 0 0 39 57 44 3 0 9 41 85 -20 39 31 16 40 24 19 38 41 13 41 15 5 8 0 0 40 21 23 3 0 12 42 86 -19 39 54 58 40 47 53 39 5 3 41 38 31 9 0 0 40 44 36 3 0 14 42 87 -19 40 18 16 41 11 2 39 28 28 42 1 32 10 0 0 41 7 23 3 0 17 43 88 -18 40 41 7 41 33 45 39 51 28 42 24 7 11 0 0 41 29 46 3 0 19 44 89 -17 41 3 34 41 56 3 40 14 2 42 46 16 12 0 0 41 51 42 3 0 22 45 90 -16 41 25 34 42 17 55 40 36 11 43 8 0 13 0 0 42 13 12 3 0 24 46 91 -15 41 47 9 42 39 21 40 57 54 43 29 17 14 0 0 42 34 17 3 0 27 46 92 -14 42 8 19 43 0 22 41 19 11 43 50 9 15 0 0 42 54 56 3 0 29 47 93 -14 42 29 2 43 20 56 41 40 3 44 10 35 16 0 0 43 15 9 3 0 32 48 94 -13 42 49 19 43 41 5 42 0 29 44 30 35 17 0 0 43 34 57 3 0 34 48 95 -12 43 9 11 44 0 48 42 20 29 44 50 9 18 0 0 43 54 18 3 0 37 49 96 -11 43 28 37 44 20 4 42 40 3 45 9 18 19 0 0 44 13 14 3 0 39 50 97 -10 43 47 37 44 38 56 42 59 11 45 28 0 20 0 0 44 31 44 3 0 42 50 98 -10 44 6 11 44 57 21 43 17 54 45 46 17 21 0 0 44 49 48 3 0 44 51 100 -9 44 24 20 45 15 21 43 36 11 46 4 9 22 0 0 45 7 27 3 0 47 52 101 -8 44 42 3 45 32 55 43 54 2 46 21 34 23 0 0 45 24 40 3 0 49 52 102 -7 44 59 21 45 50 4 44 11 27 46 38 35 24 0 0 45 41 28 3 0 52 53 103 -7 45 16 13 46 6 48 44 28 28 46 55 10 25 0 0 45 57 50 3 0 55 54 105 -6 45 32 39 46 23 6 44 45 2 47 11 20 26 0 0 46 13 47 3 0 57 54 106 -5 45 48 41 46 38 59 45 1 12 47 27 4 27 0 0 46 29 19 3 1 0 55 107 -4 46 4 17 46 54 27 45 16 56 47 42 24 28 0 0 46 44 27 3 1 2 55 109 -4 46 19 29 47 9 30 45 32 15 47 57 19 29 0 0 46 59 9 3 1 5 56 110 -3 46 34 15 47 24 8 45 47 9 48 11 50 30 0 0 47 13 27 3 1 7 57 112 -2 46 48 37 47 38 22 46 1 38 48 25 56 31 0 0 47 27 20 3 1 10 57 113 -1 47 2 34 47 52 11 46 15 43 48 39 37 32 0 0 47 40 49 3 1 13 58 115 -1 47 16 7 48 5 36 46 29 23 48 52 55 Uncertainty in time = +/- 3 secs Prediction of 2012 Jul 16.0 Data for the target star ------------------------ * name: 2UCAC 41675180 * constellation : Taurus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 05 33 02.8512 DE: +28 14 13.071 * position source: mpos:UCAC4 pm:UCAC4 * standard error: RA,DE ["]: ( .033, .038 ) * V mag [mag]: 12.8 * B mag [mag]: 0.0 * Apparent position with proper motion RA(deg): 83.4641507492 DE(deg): 28.2435889832 * Equation of equinoxes (radians) : 0.000070881048544 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (972) Cohnia approx. diameter [km]: 80 approx. diameter ["]: .041 distance from Earth [AU]: 2.69600 * orbital information: orbit source: Preston date of fit: 2012 Jul 16 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1150 number of rejected observations: 59 time covered by the observations: 1906 Jan 22 - 2012 Jan 03 1 sigma uncertainty ellipse (major, minor, PA): 0.020, 0.008, 97° remarks: * orbital elements for (972) Cohnia : Mean anomaly = 28.65474215 deg Arg. of pericenter = 94.44849176 deg Long. of node = 281.54551387 deg Inclination = 8.36433210 deg Eccentricity = 0.23431622 Semimajor axis = 3.06124025 AU Perihelion dist = 2.34394201 AU Mag: H = 9.54, G = 0.15 Epoch of elements : MJD 56163.12500000 TDT (2012 Aug 24.125) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Aug 24 972 Cohnia 3h 2.5m UT 12.8 5 33 2.851 28 14 13.072UCAC 41675180 0.0 14.7 80 2.8 2.696 3.994 1.46 64.8244 28.237 134.96 10.99 3.0424 -0.01089 0.39160 16.18094 0.44927 -0.00509 -0.00006 2000 28.0796892012 821.00000 94.448492281.545514 8.3643320.23431622 3.0612403 2.3439420 9.5 5.00.15 RATE 1.8401700 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.039 0.039 92 1.95 0.039 0 0 2 1 056124.0020120824_675180 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 16, 18:08 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org