IOTA/IOTA-ES occultation update for (98) Ianthe / TYC 1778-00824-1 event on 2008 Mar 01, 13:34 UT Visible from SE Asia, India Summary ------- On 2008 Mar 01 UT, the 105 km diameter asteroid (98) Ianthe will occult a 12.6 mag star in the constellation Triangulum for observers along a path across SE Asia, India. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.8 mag to 14.2 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 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: 96 * date and approx. time of event: 2008 Mar 01, 13:36 - 2008 Mar 01, 13:38 UT * magnitude of target star: 12.6 * magnitude drop [mag]: 1.8 * estimated maximum duration [s]: 3.5 * Moon: 36 % sunlit, 137° distance * Sun: 64° distance * rough path description: SE Asia, India The occultation path -------------------- * approximate projected width [km]: 109 * 1 sigma uncertainty interval [path widths]: +/- 0.41 * 1 sigma uncertainty interval [seconds]: +/- 2.2 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .037 +/- .020) * 1 sigma uncertainty ellipse (major, minor, PA): ( .037", .020", 88° ) * approx speed of asteroid's shadow [km/s]: 29.4741 * website for maps: http://lunar-occultations.com/iota/asteroids/astrndx.htm http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 1778-00824-1 by 98 Ianthe on 2008 Mar 1 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 67 0 0 16 3 56 13 36 33 57 299 0 15 34 21 16 33 26 15 10 2 16 57 35 68 0 0 15 59 5 13 36 37 56 298 -1 15 29 28 16 28 37 15 5 9 16 52 47 69 0 0 15 53 40 13 36 40 55 298 -2 15 24 2 16 23 14 14 59 41 16 47 25 70 0 0 15 47 42 13 36 43 54 298 -3 15 18 2 16 17 17 14 53 40 16 41 30 71 0 0 15 41 10 13 36 46 53 297 -4 15 11 28 16 10 47 14 47 4 16 35 1 72 0 0 15 34 4 13 36 49 52 297 -5 15 4 21 16 3 43 14 39 55 16 27 59 73 0 0 15 26 25 13 36 52 51 297 -6 14 56 39 15 56 6 14 32 12 16 20 24 74 0 0 15 18 12 13 36 55 50 297 -7 14 48 24 15 47 56 14 23 55 16 12 15 75 0 0 15 9 26 13 36 58 49 297 -8 14 39 35 15 39 12 14 15 4 16 3 33 76 0 0 15 0 5 13 37 1 48 297 -9 14 30 12 15 29 54 14 5 39 15 54 18 77 0 0 14 50 11 13 37 4 47 297 -10 14 20 15 15 20 3 13 55 40 15 44 29 78 0 0 14 39 44 13 37 7 46 297 -11 14 9 45 15 9 38 13 45 6 15 34 7 79 0 0 14 28 42 13 37 9 46 297 -12 13 58 40 14 58 40 13 33 59 15 23 11 80 0 0 14 17 7 13 37 12 45 297 -13 13 47 2 14 47 8 13 22 18 15 11 41 81 0 0 14 4 58 13 37 15 44 297 -14 13 34 49 14 35 2 13 10 3 14 59 38 82 0 0 13 52 15 13 37 18 43 297 -15 13 22 3 14 22 23 12 57 14 14 47 2 83 0 0 13 38 58 13 37 20 42 297 -16 13 8 43 14 9 10 12 43 50 14 33 52 84 0 0 13 25 8 13 37 23 41 297 -16 12 54 48 13 55 23 12 29 53 14 20 8 85 0 0 13 10 44 13 37 25 40 297 -17 12 40 20 13 41 2 12 15 21 14 5 51 86 0 0 12 55 45 13 37 28 39 297 -18 12 25 18 13 26 8 12 0 16 13 51 0 87 0 0 12 40 14 13 37 30 38 297 -19 12 9 42 13 10 41 11 44 37 13 35 36 88 0 0 12 24 8 13 37 33 37 297 -20 11 53 32 12 54 39 11 28 23 13 19 38 89 0 0 12 7 29 13 37 35 36 297 -21 11 36 48 12 38 4 11 11 36 13 3 7 90 0 0 11 50 16 13 37 37 35 297 -22 11 19 31 12 20 56 10 54 14 12 46 2 91 0 0 11 32 29 13 37 40 34 297 -23 11 1 40 12 3 14 10 36 19 12 28 23 92 0 0 11 14 9 13 37 42 33 297 -24 10 43 15 11 44 58 10 17 50 12 10 12 93 0 0 10 55 15 13 37 44 32 297 -25 10 24 16 11 26 10 9 58 48 11 51 27 94 0 0 10 35 48 13 37 46 31 297 -26 10 4 44 11 6 48 9 39 12 11 32 9 95 0 0 10 15 48 13 37 48 30 297 -27 9 44 39 10 46 52 9 19 2 11 12 18 96 0 0 9 55 14 13 37 50 29 298 -28 9 24 0 10 26 24 8 58 19 10 51 53 97 0 0 9 34 8 13 37 52 27 298 -29 9 2 48 10 5 22 8 37 3 10 30 56 98 0 0 9 12 28 13 37 54 26 298 -30 8 41 3 9 43 48 8 15 14 10 9 26 99 0 0 8 50 16 13 37 56 25 298 -31 8 18 46 9 21 41 7 52 52 9 47 24 100 0 0 8 27 31 13 37 58 24 298 -32 7 55 56 8 59 2 7 29 57 9 24 49 101 0 0 8 4 14 13 37 59 23 298 -33 7 32 33 8 35 50 7 6 30 9 1 42 102 0 0 7 40 25 13 38 1 22 298 -34 7 8 38 8 12 7 6 42 31 8 38 3 103 0 0 7 16 4 13 38 2 21 298 -35 6 44 12 7 47 51 6 17 59 8 13 52 104 0 0 6 51 11 13 38 4 20 298 -36 6 19 13 7 23 4 5 52 57 7 49 9 105 0 0 6 25 47 13 38 5 19 298 -37 5 53 44 6 57 46 5 27 22 7 23 56 106 0 0 5 59 53 13 38 7 18 298 -38 5 27 43 6 31 57 5 1 17 6 58 11 107 0 0 5 33 27 13 38 8 17 298 -39 5 1 12 6 5 37 4 34 41 6 31 56 108 0 0 5 6 31 13 38 9 16 299 -40 4 34 10 5 38 47 4 7 35 6 5 11 109 0 0 4 39 6 13 38 10 15 299 -41 4 6 39 5 11 27 3 39 58 5 37 56 110 0 0 4 11 11 13 38 11 14 299 -42 3 38 38 4 43 38 3 11 53 5 10 11 111 0 0 3 42 47 13 38 12 12 299 -43 3 10 8 4 15 20 2 43 18 4 41 58 112 0 0 3 13 54 13 38 13 11 299 -44 2 41 10 3 46 33 2 14 15 4 13 16 113 0 0 2 44 34 13 38 14 10 299 -44 2 11 44 3 17 19 1 44 45 3 44 6 114 0 0 2 14 46 13 38 15 9 299 -45 1 41 51 2 47 36 1 14 46 3 14 28 115 0 0 1 44 32 13 38 15 8 299 -46 1 11 30 2 17 28 0 44 21 2 44 24 116 0 0 1 13 51 13 38 16 7 299 -47 0 40 44 1 46 52 0 13 30 2 13 53 117 0 0 0 42 45 13 38 17 6 299 -48 0 9 32 1 15 52 - 0 17 46 1 42 57 118 0 0 0 11 13 13 38 17 5 299 -49 - 0 22 5 0 44 26 - 0 49 27 1 11 36 119 0 0 - 0 20 42 13 38 17 3 299 -50 - 0 54 5 0 12 36 - 1 21 33 0 39 50 120 0 0 - 0 53 1 13 38 17 2 299 -51 - 1 26 30 - 0 19 38 - 1 54 1 0 7 41 121 0 0 - 1 25 42 13 38 18 1 299 -52 - 1 59 16 - 0 52 14 - 2 26 52 - 0 24 51 122 0 0 - 1 58 45 13 38 18 0 299 -52 .. .. .. - 1 25 12 .. .. .. - 0 57 45 Uncertainty in time = +/- 3 secs [Prediction of 2008 Feb 14.0] Data for the target star ------------------------ * name: TYC 1778-00824-1 * constellation : Triangulum * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 02 29 17.8757 DE: +28 47 04.584 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .035, .019 ) * V mag [mag]: 12.6 * B mag [mag]: 13.3 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (98) Ianthe approx. diameter [km]: 105 approx. diameter ["]: .051 distance from Earth [AU]: 2.84000 * orbital information: orbit source: Preston date of fit: 2008 Feb 13 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 707 number of rejected observations: 47 time covered by the observations: 1927 Aug 30 - 2008 Jan 15 1 sigma uncertainty ellipse (major, minor, PA): 0.010, 0.008, 60° remarks: * orbital elements for (98) Ianthe : Mean anomaly = 294.52816610 deg Arg. of pericenter = 158.49916703 deg Long. of node = 354.13018518 deg Inclination = 15.60972487 deg Eccentricity = 0.18928519 Semimajor axis = 2.68542831 AU Perihelion dist = 2.17711652 AU Mag: H = 8.76, G = 0.15 Epoch of elements : MJD 54526.56600000 TDT (2008 Mar 01.566) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Mar 1 98 Ianthe 13h 34.8m UT 12.6 2 29 17.876 28 47 4.58TYC 1778-00824-1 13.3 14.2 105 3.5 2.840 3.822 11.36 33.8948 28.781 -20.63 -7.31 13.5801 0.05595 -0.25295 16.22628 3.66945 0.00470 0.00225 2000 293.0576002008 224.00000158.499167354.130185 15.6097250.18928519 2.6854283 2.1771165 8.8 5.00.15 RATE 2.2396680 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.037 0.020 88 1.41 0.021 0 54510.5020080301_0824-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Feb 14, 02:27 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org