IOTA/IOTA-ES occultation update for (88) Thisbe / TYC 6161-01200-1 event on 2012 Dec 23, 10:15 UT Visible from SE USA Summary ------- On 2012 Dec 23 UT, the 220 km diameter asteroid (88) Thisbe will occult a 10.4 mag star in the constellation Libra for observers along a path across SE USA. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.5 mag to 12.8 mag (the magnitude of the asteroid) for at most 5.9 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: 99 * date and approx. time of event: 2012 Dec 23, 10:13 - 2012 Dec 23, 10:13 UT * geocentric midpoint of event [JD]: 2456284.92755 * magnitude of target star: 10.4 * magnitude drop [mag]: 2.5 * estimated maximum duration [s]: 5.9 * Moon: 79 % sunlit, 174° distance * Sun: 49° distance * rough path description: SE USA The occultation path -------------------- * approximate projected width [km]: 235 * 1 sigma uncertainty interval [path widths]: +/- 0.32 * 1 sigma uncertainty interval [seconds]: +/- 1.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .023 +/- .029) * 1 sigma uncertainty ellipse (major, minor, PA): ( .029", .023", 0° ) * approx speed of asteroid's shadow [km/s]: 37.4224 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6161-01200-1 by 88 Thisbe on 2012 Dec 23 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 -100 0 0 36 56 30 10 13 1 0 115 -42 35 46 38 .. .. .. 35 2 12 .. .. .. - 99 0 0 36 33 45 10 13 1 1 116 -42 35 23 44 37 44 22 34 39 12 38 29 53 - 98 0 0 36 10 37 10 13 1 2 116 -41 35 0 26 37 21 23 34 15 49 38 7 1 - 97 0 0 35 47 6 10 13 1 3 117 -40 34 36 46 36 58 1 33 52 3 37 43 45 - 96 0 0 35 23 12 10 13 2 4 118 -39 34 12 44 36 34 16 33 27 55 37 20 6 - 95 0 0 34 58 56 10 13 2 5 118 -38 33 48 19 36 10 9 33 3 25 36 56 4 - 94 0 0 34 34 17 10 13 2 6 119 -38 33 23 32 35 45 39 32 38 32 36 31 40 - 93 0 0 34 9 17 10 13 2 7 119 -37 32 58 23 35 20 47 32 13 19 36 6 54 - 92 0 0 33 43 55 10 13 3 8 120 -36 32 32 53 34 55 33 31 47 43 35 41 45 - 91 0 0 33 18 12 10 13 3 9 120 -35 32 7 2 34 29 58 31 21 47 35 16 15 - 90 0 0 32 52 7 10 13 4 10 121 -34 31 40 50 34 4 2 30 55 31 34 50 24 - 89 0 0 32 25 43 10 13 4 10 121 -33 31 14 18 33 37 44 30 28 54 34 24 11 - 88 0 0 31 58 58 10 13 5 11 122 -32 30 47 26 33 11 7 30 1 58 33 57 38 - 87 0 0 31 31 53 10 13 5 12 123 -31 30 20 15 32 44 9 29 34 43 33 30 45 - 86 0 0 31 4 29 10 13 6 13 123 -30 29 52 45 32 16 52 29 7 8 33 3 32 - 85 0 0 30 36 47 10 13 7 14 124 -29 29 24 56 31 49 16 28 39 16 32 36 0 - 84 0 0 30 8 46 10 13 8 15 124 -28 28 56 50 31 21 21 28 11 6 32 8 10 - 83 0 0 29 40 28 10 13 8 16 125 -28 28 28 26 30 53 9 27 42 38 31 40 1 - 82 0 0 29 11 53 10 13 9 17 125 -27 27 59 45 30 24 38 27 13 55 31 11 34 - 81 0 0 28 43 1 10 13 10 18 126 -26 27 30 49 29 55 52 26 44 55 30 42 50 - 80 0 0 28 13 53 10 13 11 19 126 -25 27 1 36 29 26 48 26 15 40 30 13 50 - 79 0 0 27 44 30 10 13 12 20 127 -24 26 32 9 28 57 30 25 46 10 29 44 34 - 78 0 0 27 14 53 10 13 14 21 127 -23 26 2 28 28 27 56 25 16 27 29 15 3 - 77 0 0 26 45 2 10 13 15 22 128 -22 25 32 34 27 58 8 24 46 30 28 45 18 - 76 0 0 26 14 57 10 13 16 23 128 -21 25 2 27 27 28 7 24 16 21 28 15 19 - 75 0 0 25 44 41 10 13 17 24 129 -20 24 32 8 26 57 53 23 46 1 27 45 6 - 74 0 0 25 14 13 10 13 19 25 129 -19 24 1 37 26 27 27 23 15 29 27 14 42 - 73 0 0 24 43 34 10 13 20 26 130 -18 23 30 57 25 56 50 22 44 47 26 44 6 - 72 0 0 24 12 45 10 13 22 27 130 -17 23 0 7 25 26 3 22 13 57 26 13 20 - 71 0 0 23 41 48 10 13 23 28 131 -16 22 29 8 24 55 6 21 42 57 25 42 23 - 70 0 0 23 10 42 10 13 25 29 131 -15 21 58 2 24 24 1 21 11 51 25 11 18 - 69 0 0 22 39 28 10 13 27 31 132 -13 21 26 48 23 52 47 20 40 37 24 40 5 - 68 0 0 22 8 8 10 13 28 32 132 -12 20 55 29 23 21 27 20 9 18 24 8 44 - 67 0 0 21 36 43 10 13 30 33 133 -11 20 24 4 22 50 1 19 37 54 23 37 18 - 66 0 0 21 5 13 10 13 32 34 134 -10 19 52 36 22 18 30 19 6 26 23 5 46 - 65 0 0 20 33 40 10 13 34 35 134 -9 19 21 4 21 46 55 18 34 55 22 34 10 - 64 0 0 20 2 3 10 13 36 36 135 -8 18 49 29 21 15 16 18 3 22 22 2 30 - 63 0 0 19 30 25 10 13 38 37 135 -7 18 17 54 20 43 36 17 31 48 21 30 48 - 62 0 0 18 58 46 10 13 40 38 136 -6 17 46 18 20 11 54 17 0 14 20 59 4 - 61 0 0 18 27 8 10 13 42 39 136 -5 17 14 42 19 40 12 16 28 40 20 27 20 - 60 0 0 17 55 30 10 13 44 40 137 -4 16 43 8 19 8 30 15 57 8 19 55 36 - 59 0 0 17 23 54 10 13 47 41 138 -3 16 11 37 18 36 51 15 25 39 19 23 53 - 58 0 0 16 52 22 10 13 49 42 138 -2 15 40 8 18 5 14 14 54 14 18 52 13 - 57 0 0 16 20 53 10 13 51 43 139 -1 15 8 45 17 33 40 14 22 53 18 20 37 Uncertainty in time = +/- 2 secs Prediction of 2012 Dec 17.0 Data for the target star ------------------------ * name: TYC 6161-01200-1 * constellation : Libra * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 14 37 35.8183 DE: -19 39 40.279 * position source: mpos:UCAC4 pm:UCAC4 * standard error: RA,DE ["]: ( .022, .029 ) * V mag [mag]: 10.4 * B mag [mag]: 11.4 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (88) Thisbe approx. diameter [km]: 220 approx. diameter ["]: .090 distance from Earth [AU]: 3.36200 * orbital information: orbit source: Preston date of fit: 2012 Jul 10 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1750 number of rejected observations: 145 time covered by the observations: 1903 Aug 06 - 2012 Apr 25 1 sigma uncertainty ellipse (major, minor, PA): 0.007, 0.004, 105° remarks: * orbital elements for (88) Thisbe : Mean anomaly = 273.78135117 deg Arg. of pericenter = 36.06053610 deg Long. of node = 276.68789115 deg Inclination = 5.21436248 deg Eccentricity = 0.16453430 Semimajor axis = 2.76814221 AU Perihelion dist = 2.31268787 AU Mag: H = 7.16, G = 0.14 Epoch of elements : MJD 56284.42800000 TDT (2012 Dec 23.428) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Dec 23 88 Thisbe 10h 15.7m UT 10.4 14 37 35.818-19 39 40.28TYC 6161-01200-1 11.4 12.8 220 5.9 3.362 3.699 -17.97 -26.8793 -19.656 25.90 -23.42 10.2612 0.11429 0.33334 19.97359 -6.87065 -0.00435 0.00112 2000 272.83374220121219.00000 36.060536276.687891 5.2143620.16453430 2.7681422 2.3126879 7.0 5.00.14 RATE 2.1400380 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.029 0.023 0 1.32 0.029 0 0 3 1 056278.0020121223_1200-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 10, 06:31 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org