IOTA/IOTA-ES occultation update for (115) Thyra / HIP 60420 event on 2012 Nov 23, 00:04 UT Visible from India, Arabia Summary ------- On 2012 Nov 23 UT, the 81 km diameter asteroid (115) Thyra will occult a 7.6 mag star in the constellation Virgo for observers along a path across India, Arabia. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.4 mag to 13.0 mag (the magnitude of the asteroid) for at most 2.3 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: . The event at a glimpse ---------------------- * Rank: 99 * date and approx. time of event: 2012 Nov 23, 00:01 - 2012 Nov 23, 00:02 UT * geocentric midpoint of event [JD]: 2456254.5031875 * magnitude of target star: 7.6 * magnitude drop [mag]: 5.4 * estimated maximum duration [s]: 2.3 * Moon: 74 % sunlit, 171° distance * Sun: 52° distance * rough path description: India, Arabia The occultation path -------------------- * approximate projected width [km]: 81 * 1 sigma uncertainty interval [path widths]: +/- 0.27 * 1 sigma uncertainty interval [seconds]: +/- 0.8 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .013 +/- .009) * 1 sigma uncertainty ellipse (major, minor, PA): ( .013", .009", 101° ) * approx speed of asteroid's shadow [km/s]: 34.3790 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 60420 by 115 Thyra on 2012 Nov 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 38 0 0 25 31 48 0 1 31 0 101 -51 25 9 20 .. .. .. 24 57 12 .. .. .. 39 0 0 25 21 1 0 1 31 1 101 -50 24 58 31 25 43 31 24 46 22 25 55 39 40 0 0 25 9 43 0 1 31 2 102 -49 24 47 10 25 32 15 24 34 59 25 44 24 41 0 0 24 57 52 0 1 31 3 102 -49 24 35 17 25 20 27 24 23 5 25 32 38 42 0 0 24 45 30 0 1 31 4 103 -48 24 22 51 25 8 7 24 10 37 25 20 19 43 0 0 24 32 34 0 1 32 5 103 -47 24 9 53 24 55 15 23 57 38 25 7 29 44 0 0 24 19 7 0 1 32 6 103 -46 23 56 23 24 41 50 23 44 5 24 54 6 45 0 0 24 5 7 0 1 32 7 104 -45 23 42 19 24 27 53 23 30 0 24 40 10 46 0 0 23 50 34 0 1 33 8 104 -44 23 27 43 24 13 23 23 15 23 24 25 42 47 0 0 23 35 28 0 1 33 8 105 -43 23 12 34 23 58 21 23 0 12 24 10 42 48 0 0 23 19 49 0 1 33 9 105 -42 22 56 52 23 42 46 22 44 28 23 55 8 49 0 0 23 3 38 0 1 34 10 105 -41 22 40 37 23 26 37 22 28 11 23 39 2 50 0 0 22 46 53 0 1 35 11 106 -40 22 23 48 23 9 56 22 11 20 23 22 23 51 0 0 22 29 35 0 1 35 12 106 -39 22 6 27 22 52 42 21 53 56 23 5 11 52 0 0 22 11 43 0 1 36 13 107 -38 21 48 31 22 34 54 21 35 59 22 47 25 53 0 0 21 53 19 0 1 37 14 107 -37 21 30 3 22 16 33 21 17 28 22 29 6 54 0 0 21 34 20 0 1 37 15 107 -36 21 11 0 21 57 39 20 58 24 22 10 14 55 0 0 21 14 48 0 1 38 16 108 -35 20 51 24 21 38 11 20 38 46 21 50 48 56 0 0 20 54 43 0 1 39 17 108 -34 20 31 15 21 18 10 20 18 34 21 30 49 57 0 0 20 34 4 0 1 40 18 108 -33 20 10 31 20 57 35 19 57 48 21 10 17 58 0 0 20 12 51 0 1 41 19 109 -32 19 49 14 20 36 26 19 36 29 20 49 10 59 0 0 19 51 4 0 1 42 20 109 -31 19 27 23 20 14 44 19 14 35 20 27 30 60 0 0 19 28 44 0 1 44 21 109 -30 19 4 59 19 52 28 18 52 8 20 5 17 61 0 0 19 5 50 0 1 45 22 110 -29 18 42 0 19 29 39 18 29 7 19 42 30 62 0 0 18 42 22 0 1 46 23 110 -28 18 18 28 19 6 15 18 5 33 19 19 9 63 0 0 18 18 21 0 1 47 24 110 -27 17 54 22 18 42 19 17 41 24 18 55 15 64 0 0 17 53 46 0 1 49 25 111 -26 17 29 42 18 17 48 17 16 42 18 30 47 65 0 0 17 28 38 0 1 50 26 111 -25 17 4 29 17 52 45 16 51 27 18 5 46 66 0 0 17 2 56 0 1 52 27 111 -24 16 38 43 17 27 8 16 25 37 17 40 11 67 0 0 16 36 41 0 1 54 29 111 -23 16 12 23 17 0 57 15 59 15 17 14 3 68 0 0 16 9 53 0 1 55 30 112 -22 15 45 30 16 34 14 15 32 20 16 47 22 69 0 0 15 42 32 0 1 57 31 112 -21 15 18 4 16 6 58 15 4 51 16 20 9 70 0 0 15 14 38 0 1 59 32 112 -20 14 50 6 15 39 9 14 36 50 15 52 23 71 0 0 14 46 12 0 2 1 33 112 -19 14 21 35 15 10 48 14 8 17 15 24 4 72 0 0 14 17 14 0 2 3 34 112 -18 13 52 32 14 41 54 13 39 11 14 55 13 73 0 0 13 47 44 0 2 5 35 113 -17 13 22 57 14 12 29 13 9 34 14 25 51 74 0 0 13 17 42 0 2 7 36 113 -16 12 52 51 13 42 32 12 39 25 13 55 56 75 0 0 12 47 10 0 2 9 37 113 -15 12 22 14 13 12 5 12 8 46 13 25 31 76 0 0 12 16 7 0 2 11 38 113 -14 11 51 6 12 41 6 11 37 35 12 54 35 77 0 0 11 44 34 0 2 13 39 113 -12 11 19 28 12 9 38 11 5 55 12 23 9 78 0 0 11 12 31 0 2 16 41 113 -11 10 47 20 11 37 39 10 33 44 11 51 13 79 0 0 10 39 58 0 2 18 42 114 -10 10 14 44 11 5 12 10 1 5 11 18 48 80 0 0 10 6 58 0 2 21 43 114 -9 9 41 39 10 32 16 9 27 58 10 45 55 81 0 0 9 33 29 0 2 23 44 114 -8 9 8 6 9 58 51 8 54 22 10 12 33 82 0 0 8 59 33 0 2 26 45 114 -7 8 34 5 9 25 0 8 20 20 9 38 44 83 0 0 8 25 11 0 2 28 46 114 -6 7 59 39 8 50 42 7 45 51 9 4 28 84 0 0 7 50 23 0 2 31 47 114 -5 7 24 46 8 15 58 7 10 56 8 29 46 85 0 0 7 15 10 0 2 34 49 114 -3 6 49 29 7 40 49 6 35 36 7 54 39 86 0 0 6 39 32 0 2 37 50 114 -2 6 13 48 7 5 15 5 59 53 7 19 8 87 0 0 6 3 32 0 2 40 51 114 -1 5 37 43 6 29 19 5 23 46 6 43 13 Uncertainty in time = +/- 1 secs Prediction of 2012 Nov 16.0 Data for the target star ------------------------ * name: HIP 60420 * constellation : Virgo * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 12 23 16.2861 DE: -09 46 17.773 * position source: mpos:HIP2 pm:HIP2 plx:HIP2 * standard error: RA,DE ["]: ( .010, .007 ) * V mag [mag]: 7.6 * B mag [mag]: 8.7 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (115) Thyra approx. diameter [km]: 81 approx. diameter ["]: .036 distance from Earth [AU]: 3.07600 * orbital information: orbit source: Preston date of fit: 2012 Jul 10 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1131 number of rejected observations: 154 time covered by the observations: 1904 Aug 02 - 2012 Mar 25 1 sigma uncertainty ellipse (major, minor, PA): 0.008, 0.006, 121° remarks: * orbital elements for (115) Thyra : Mean anomaly = 107.31425120 deg Arg. of pericenter = 96.70214131 deg Long. of node = 308.92842432 deg Inclination = 11.60026649 deg Eccentricity = 0.19236898 Semimajor axis = 2.37923352 AU Perihelion dist = 1.92154279 AU Mag: H = 7.50, G = 0.12 Epoch of elements : MJD 56254.00300000 TDT (2012 Nov 23.003) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Nov 23 115 Thyra 0h 4.6m UT 7.6 12 23 16.286- 9 46 17.77HIP 60420 8.7 13.0 81 2.3 3.076 3.198 -29.02 122.2970 -9.764 175.46 -20.38 0.0765 -0.05237 -0.08525 16.53782-10.15056 -0.00437 0.00144 2000 106.23918820121119.00000 96.702141308.928424 11.6002660.19236898 2.3792335 1.9215428 7.5 5.00.12 RATE 2.6856440 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.013 0.009 101 1.27 0.010 0 0 1-3 056247.0020121123__60420 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 10, 03:04 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org