IOTA/IOTA-ES occultation update for (160) Una / TYC 6866-00084-1 event on 2008 Mar 31, 06:25 UT Visible from Argentina, Chile Summary ------- On 2008 Mar 31 UT, the 81 km diameter asteroid (160) Una will occult a 11.8 mag star in the constellation Sagittarius for observers along a path across Argentina, Chile. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.8 mag to 14.5 mag (the magnitude of the asteroid) for at most 5.3 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: 83 * date and approx. time of event: 2008 Mar 31, 06:19 - 2008 Mar 31, 06:25 UT * magnitude of target star: 11.8 * magnitude drop [mag]: 2.8 * estimated maximum duration [s]: 5.3 * Moon: 37 % sunlit, 18° distance * Sun: 93° distance * rough path description: Argentina, Chile The occultation path -------------------- * approximate projected width [km]: 98 * 1 sigma uncertainty interval [path widths]: +/- 0.63 * 1 sigma uncertainty interval [seconds]: +/- 3.1 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .028 +/- .026) * 1 sigma uncertainty ellipse (major, minor, PA): ( .028", .026", 89° ) * approx speed of asteroid's shadow [km/s]: 15.1974 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6866-00084-1 by 160 Una on 2008 Mar 31 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 -109 0 0 -27 13 20 6 19 15 1 120 -63 -27 44 43 -26 42 11 -28 24 36 .. .. .. -108 0 0 -27 45 29 6 19 16 2 120 -63 -28 16 57 -27 14 14 -28 56 57 .. .. .. -107 0 0 -28 17 48 6 19 16 3 119 -63 -28 49 21 -27 46 28 -29 29 27 .. .. .. -106 0 0 -28 50 16 6 19 17 4 119 -63 -29 21 55 -28 18 52 -30 2 7 -27 39 37 -105 0 0 -29 22 53 6 19 17 5 118 -63 -29 54 36 -28 51 24 -30 34 55 -28 12 3 -104 0 0 -29 55 37 6 19 18 6 118 -63 -30 27 25 -29 24 3 -31 7 50 -28 44 37 -103 0 0 -30 28 28 6 19 19 7 117 -63 -31 0 20 -29 56 49 -31 40 51 -29 17 17 -102 0 0 -31 1 23 6 19 20 8 117 -62 -31 33 20 -30 29 41 -32 13 57 -29 50 4 -101 0 0 -31 34 23 6 19 22 9 116 -62 -32 6 24 -31 2 36 -32 47 5 -30 22 54 -100 0 0 -32 7 25 6 19 23 10 116 -62 -32 39 30 -31 35 35 -33 20 17 -30 55 48 - 99 0 0 -32 40 29 6 19 25 11 115 -61 -33 12 37 -32 8 35 -33 53 29 -31 28 44 - 98 0 0 -33 13 33 6 19 27 12 115 -61 -33 45 45 -32 41 36 -34 26 41 -32 1 41 - 97 0 0 -33 46 37 6 19 29 13 114 -60 -34 18 52 -33 14 37 -34 59 52 -32 34 38 - 96 0 0 -34 19 39 6 19 31 14 113 -60 -34 51 57 -33 47 36 -35 33 1 -33 7 34 - 95 0 0 -34 52 38 6 19 33 15 113 -59 -35 24 59 -34 20 33 -36 6 6 -33 40 27 - 94 0 0 -35 25 33 6 19 35 16 112 -59 -35 57 56 -34 53 25 -36 39 6 -34 13 17 - 93 0 0 -35 58 23 6 19 38 17 112 -58 -36 30 48 -35 26 13 -37 12 1 -34 46 2 - 92 0 0 -36 31 6 6 19 40 18 111 -58 -37 3 33 -35 58 54 -37 44 48 -35 18 41 - 91 0 0 -37 3 42 6 19 43 19 110 -57 -37 36 10 -36 31 29 -38 17 27 -35 51 13 - 90 0 0 -37 36 9 6 19 46 20 110 -57 -38 8 39 -37 3 54 -38 49 57 -36 23 38 - 89 0 0 -38 8 26 6 19 49 21 109 -56 -38 40 57 -37 36 11 -39 22 17 -36 55 53 - 88 0 0 -38 40 33 6 19 52 22 108 -55 -39 13 4 -38 8 17 -39 54 25 -37 27 58 - 87 0 0 -39 12 28 6 19 55 22 107 -55 -39 45 0 -38 40 12 -40 26 21 -37 59 52 - 86 0 0 -39 44 10 6 19 58 23 107 -54 -40 16 42 -39 11 54 -40 58 3 -38 31 34 - 85 0 0 -40 15 39 6 20 2 24 106 -53 -40 48 10 -39 43 22 -41 29 31 -39 3 3 - 84 0 0 -40 46 52 6 20 5 25 105 -53 -41 19 23 -40 14 37 -42 0 43 -39 34 18 - 83 0 0 -41 17 50 6 20 9 26 104 -52 -41 50 20 -40 45 35 -42 31 39 -40 5 18 - 82 0 0 -41 48 32 6 20 12 27 103 -51 -42 21 1 -41 16 18 -43 2 18 -40 36 2 - 81 0 0 -42 18 56 6 20 16 28 103 -50 -42 51 23 -41 46 44 -43 32 39 -41 6 29 - 80 0 0 -42 49 2 6 20 20 29 102 -50 -43 21 28 -42 16 51 -44 2 41 -41 36 39 - 79 0 0 -43 18 49 6 20 24 29 101 -49 -43 51 13 -42 46 40 -44 32 23 -42 6 31 - 78 0 0 -43 48 16 6 20 28 30 100 -48 -44 20 38 -43 16 10 -45 1 45 -42 36 3 - 77 0 0 -44 17 23 6 20 32 31 99 -47 -44 49 42 -43 45 20 -45 30 46 -43 5 16 - 76 0 0 -44 46 9 6 20 36 32 98 -47 -45 18 25 -44 14 8 -45 59 26 -43 34 8 - 75 0 0 -45 14 34 6 20 40 33 97 -46 -45 46 46 -44 42 36 -46 27 43 -44 2 39 - 74 0 0 -45 42 36 6 20 44 33 96 -45 -46 14 45 -45 10 41 -46 55 37 -44 30 49 - 73 0 0 -46 10 15 6 20 48 34 95 -44 -46 42 21 -45 38 24 -47 23 8 -44 58 36 - 72 0 0 -46 37 31 6 20 52 35 94 -44 -47 9 33 -46 5 44 -47 50 15 -45 26 1 - 71 0 0 -47 4 24 6 20 57 35 93 -43 -47 36 21 -46 32 41 -48 16 59 -45 53 2 - 70 0 0 -47 30 52 6 21 1 36 92 -42 -48 2 45 -46 59 13 -48 43 17 -46 19 40 - 69 0 0 -47 56 56 6 21 5 37 91 -41 -48 28 45 -47 25 22 -49 9 10 -46 45 54 - 68 0 0 -48 22 35 6 21 9 38 90 -41 -48 54 19 -47 51 5 -49 34 39 -47 11 43 - 67 0 0 -48 47 49 6 21 14 38 89 -40 -49 19 28 -48 16 24 -49 59 41 -47 37 8 - 66 0 0 -49 12 38 6 21 18 39 88 -39 -49 44 12 -48 41 18 -50 24 18 -48 2 8 - 65 0 0 -49 37 1 6 21 23 40 87 -38 -50 8 30 -49 5 46 -50 48 29 -48 26 42 - 64 0 0 -50 0 58 6 21 27 40 85 -38 -50 32 22 -49 29 49 -51 12 14 -48 50 51 - 63 0 0 -50 24 30 6 21 31 41 84 -37 -50 55 47 -49 53 26 -51 35 33 -49 14 35 - 62 0 0 -50 47 35 6 21 36 41 83 -36 -51 18 47 -50 16 37 -51 58 25 -49 37 53 - 61 0 0 -51 10 15 6 21 40 42 82 -36 -51 41 21 -50 39 22 -52 20 51 -50 0 45 - 60 0 0 -51 32 28 6 21 45 43 81 -35 -52 3 28 -51 1 41 -52 42 51 -50 23 11 - 59 0 0 -51 54 14 6 21 49 43 79 -34 -52 25 9 -51 23 33 -53 4 24 -50 45 11 - 58 0 0 -52 15 35 6 21 53 44 78 -33 -52 46 23 -51 45 0 -53 25 30 -51 6 45 - 57 0 0 -52 36 30 6 21 58 44 77 -33 -53 7 11 -52 6 0 -53 46 10 -51 27 53 - 56 0 0 -52 56 58 6 22 2 45 76 -32 -53 27 33 -52 26 35 -54 6 24 -51 48 35 - 55 0 0 -53 17 0 6 22 7 45 74 -31 -53 47 29 -52 46 43 -54 26 12 -52 8 51 - 54 0 0 -53 36 36 6 22 11 46 73 -31 -54 6 59 -53 6 25 -54 45 33 -52 28 41 - 53 0 0 -53 55 46 6 22 15 46 72 -30 -54 26 3 -53 25 42 -55 4 29 -52 48 5 - 52 0 0 -54 14 31 6 22 20 47 70 -29 -54 44 40 -53 44 33 -55 22 59 -53 7 4 - 51 0 0 -54 32 49 6 22 24 47 69 -29 -55 2 53 -54 2 58 -55 41 3 -53 25 37 - 50 0 0 -54 50 42 6 22 28 48 68 -28 -55 20 40 -54 20 57 -55 58 41 -53 43 44 - 49 0 0 -55 8 10 6 22 33 48 66 -27 -55 38 1 -54 38 31 -56 15 54 -54 1 26 - 48 0 0 -55 25 13 6 22 37 48 65 -27 -55 54 57 -54 55 40 -56 32 42 -54 18 43 - 47 0 0 -55 41 51 6 22 41 49 64 -26 -56 11 28 -55 12 24 -56 49 5 -54 35 34 - 46 0 0 -55 58 4 6 22 46 49 62 -26 -56 27 35 -55 28 43 -57 5 3 -54 52 1 - 45 0 0 -56 13 52 6 22 50 49 61 -25 -56 43 17 -55 44 38 -57 20 37 -55 8 3 - 44 0 0 -56 29 16 6 22 54 50 59 -24 -56 58 34 -56 0 8 -57 35 47 -55 23 41 - 43 0 0 -56 44 15 6 22 58 50 58 -24 -57 13 28 -56 15 14 -57 50 32 -55 38 55 - 42 0 0 -56 58 51 6 23 2 51 56 -23 -57 27 58 -56 29 56 -58 4 54 -55 53 44 - 41 0 0 -57 13 3 6 23 7 51 55 -23 -57 42 4 -56 44 14 -58 18 52 -56 8 10 - 40 0 0 -57 26 52 6 23 11 51 53 -22 -57 55 46 -56 58 9 -58 32 27 -56 22 12 - 39 0 0 -57 40 17 6 23 15 51 52 -21 -58 9 6 -57 11 40 -58 45 38 -56 35 50 - 38 0 0 -57 53 20 6 23 19 52 50 -21 -58 22 2 -57 24 48 -58 58 27 -56 49 5 - 37 0 0 -58 5 59 6 23 23 52 49 -20 -58 34 36 -57 37 33 -59 10 54 -57 1 58 - 36 0 0 -58 18 17 6 23 27 52 47 -20 -58 46 47 -57 49 56 -59 22 58 -57 14 27 - 35 0 0 -58 30 11 6 23 31 53 46 -19 -58 58 37 -58 1 56 -59 34 40 -57 26 35 - 34 0 0 -58 41 44 6 23 35 53 44 -18 -59 10 4 -58 13 35 -59 46 0 -57 38 19 - 33 0 0 -58 52 55 6 23 39 53 43 -18 -59 21 9 -58 24 51 -59 56 59 -57 49 42 - 32 0 0 -59 3 45 6 23 43 53 41 -17 -59 31 54 -58 35 45 -60 7 36 -58 0 43 - 31 0 0 -59 14 13 6 23 47 53 40 -17 -59 42 16 -58 46 19 -60 17 52 -58 11 23 - 30 0 0 -59 24 20 6 23 51 54 38 -16 -59 52 18 -58 56 30 -60 27 48 -58 21 41 - 29 0 0 -59 34 6 6 23 55 54 36 -16 -60 1 59 -59 6 21 -60 37 23 -58 31 38 - 28 0 0 -59 43 31 6 23 59 54 35 -15 -60 11 20 -59 15 51 -60 46 37 -58 41 13 - 27 0 0 -59 52 36 6 24 2 54 33 -15 -60 20 20 -59 25 1 -60 55 31 -58 50 29 - 26 0 0 -60 1 20 6 24 6 54 32 -14 -60 29 0 -59 33 50 -61 4 5 -58 59 23 - 25 0 0 -60 9 45 6 24 10 54 30 -14 -60 37 20 -59 42 19 -61 12 20 -59 7 57 - 24 0 0 -60 17 50 6 24 14 55 28 -13 -60 45 21 -59 50 28 -61 20 15 -59 16 11 - 23 0 0 -60 25 35 6 24 18 55 27 -13 -60 53 2 -59 58 17 -61 27 51 -59 24 6 - 22 0 0 -60 33 0 6 24 21 55 25 -12 -61 0 24 -60 5 46 -61 35 7 -59 31 40 - 21 0 0 -60 40 7 6 24 25 55 24 -12 -61 7 26 -60 12 56 -61 42 5 -59 38 55 - 20 0 0 -60 46 54 6 24 29 55 22 -11 -61 14 10 -60 19 47 -61 48 44 -59 45 50 - 19 0 0 -60 53 22 6 24 33 55 20 -11 -61 20 34 -60 26 19 -61 55 4 -59 52 26 - 18 0 0 -60 59 32 6 24 36 55 19 -10 -61 26 41 -60 32 32 -62 1 6 -59 58 43 - 17 0 0 -61 5 23 6 24 40 55 17 -10 -61 32 28 -60 38 26 -62 6 50 -60 4 41 - 16 0 0 -61 10 55 6 24 44 55 16 -9 -61 37 58 -60 44 2 -62 12 15 -60 10 20 - 15 0 0 -61 16 10 6 24 47 55 14 -9 -61 43 9 -60 49 19 -62 17 23 -60 15 41 - 14 0 0 -61 21 6 6 24 51 55 12 -8 -61 48 2 -60 54 17 -62 22 12 -60 20 43 - 13 0 0 -61 25 44 6 24 54 55 11 -8 -61 52 38 -60 58 58 -62 26 45 -60 25 27 - 12 0 0 -61 30 4 6 24 58 55 9 -7 -61 56 55 -61 3 20 -62 30 59 -60 29 52 - 11 0 0 -61 34 6 6 25 2 55 8 -7 -62 0 55 -61 7 25 -62 34 56 -60 34 0 - 10 0 0 -61 37 50 6 25 5 55 6 -6 -62 4 38 -61 11 12 -62 38 36 -60 37 49 - 9 0 0 -61 41 17 6 25 9 55 4 -6 -62 8 3 -61 14 40 -62 41 58 -60 41 20 - 8 0 0 -61 44 27 6 25 12 55 3 -5 -62 11 11 -61 17 52 -62 45 4 -60 44 33 - 7 0 0 -61 47 19 6 25 16 55 1 -5 -62 14 1 -61 20 45 -62 47 52 -60 47 29 - 6 0 0 -61 49 54 6 25 19 55 360 -4 -62 16 34 -61 23 21 -62 50 23 -60 50 7 - 5 0 0 -61 52 11 6 25 23 55 358 -4 -62 18 50 -61 25 40 -62 52 38 -60 52 27 - 4 0 0 -61 54 11 6 25 26 55 356 -3 -62 20 49 -61 27 42 -62 54 36 -60 54 30 - 3 0 0 -61 55 54 6 25 30 55 355 -3 -62 22 32 -61 29 26 -62 56 16 -60 56 15 - 2 0 0 -61 57 20 6 25 33 55 353 -2 -62 23 57 -61 30 52 -62 57 40 -60 57 43 - 1 0 0 -61 58 29 6 25 37 55 352 -2 -62 25 5 -61 32 2 -62 58 48 -60 58 54 0 0 0 -61 59 21 6 25 40 55 350 -1 -62 25 56 -61 32 54 -62 59 39 -60 59 47 1 0 0 -61 59 56 6 25 44 55 348 -1 -62 26 31 -61 33 30 -63 0 13 -61 0 22 2 0 0 -62 0 14 6 25 47 55 347 0 -62 26 49 -61 33 48 -63 0 30 -61 0 40 Uncertainty in time = +/- 4 secs [Prediction of 2008 Mar 28.0] Data for the target star ------------------------ * name: TYC 6866-00084-1 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 35 38.3628 DE: -27 03 53.083 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .023, .024 ) * V mag [mag]: 11.8 * B mag [mag]: 12.5 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (160) Una approx. diameter [km]: 81 approx. diameter ["]: .042 distance from Earth [AU]: 2.67200 * orbital information: orbit source: Preston date of fit: 2008 Mar 27 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 865 number of rejected observations: 134 time covered by the observations: 1910 Oct 12 - 2007 Aug 07 1 sigma uncertainty ellipse (major, minor, PA): 0.016, 0.011, 86° remarks: * orbital elements for (160) Una : Mean anomaly = 201.72394142 deg Arg. of pericenter = 49.88070612 deg Long. of node = 8.80702380 deg Inclination = 3.82186663 deg Eccentricity = 0.06607127 Semimajor axis = 2.72911188 AU Perihelion dist = 2.54879599 AU Mag: H = 9.01, G = 0.15 Epoch of elements : MJD 54556.26800000 TDT (2008 Mar 31.268) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Mar 31 160 Una 6h 25.0m UT 11.8 18 35 38.363-27 3 53.08TYC 6866-00084-1 12.5 14.5 81 5.3 2.672 2.108 -2.02 -6.3515 -27.065 84.78 4.32 6.4172 -0.03907 -0.56356 8.55581 -0.61449 -0.00578 -0.00034 2000 200.3536872008 325.00000 49.880706 8.807024 3.8218670.06607127 2.7291119 2.5487960 9.1 5.00.15 RATE 2.1861100 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.028 0.026 89 1.63 0.026 0 54553.5020080331_0084-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 28, 06:07 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org