IOTA/IOTA-ES occultation update for (299) Thora / TYC 1879-00184-1 event on 2012 Sep 16, 23:41 UT Visible from India, Africa Summary ------- On 2012 Sep 16 UT, the 17 km diameter asteroid (299) Thora will occult a 8.4 mag star in the constellation Gemini for observers along a path across India, Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 7.8 mag to 16.2 mag (the magnitude of the asteroid) for at most 0.7 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: 36 * date and approx. time of event: 2012 Sep 16, 23:36 - 2012 Sep 16, 23:40 UT * geocentric midpoint of event [JD]: 2456187.4868 * magnitude of target star: 8.4 * magnitude drop [mag]: 7.8 * estimated maximum duration [s]: 0.7 * Moon: 1 % sunlit, 90° distance * Sun: 78° distance * rough path description: India, Africa The occultation path -------------------- * approximate projected width [km]: 17 * 1 sigma uncertainty interval [path widths]: +/- 1.83 * 1 sigma uncertainty interval [seconds]: +/- 1.8 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .028 +/- .018) * 1 sigma uncertainty ellipse (major, minor, PA): ( .028", .018", 93° ) * approx speed of asteroid's shadow [km/s]: 23.3039 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 1879-00184-1 by 299 Thora on 2012 Sep 16 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 17 0 0 0 21 41 23 36 27 1 67 -77 0 16 40 0 26 42 - 0 1 43 0 45 4 18 0 0 0 47 15 23 36 27 2 67 -76 0 42 14 0 52 16 0 23 52 1 10 38 19 0 0 1 12 43 23 36 28 3 67 -75 1 7 42 1 17 44 0 49 20 1 36 4 20 0 0 1 38 3 23 36 28 4 67 -74 1 33 3 1 43 4 1 14 42 2 1 24 21 0 0 2 3 17 23 36 28 5 67 -73 1 58 16 2 8 17 1 39 56 2 26 36 22 0 0 2 28 21 23 36 29 6 67 -72 2 23 21 2 33 21 2 5 2 2 51 40 23 0 0 2 53 17 23 36 30 7 67 -71 2 48 17 2 58 17 2 29 59 3 16 35 24 0 0 3 18 4 23 36 30 9 67 -70 3 13 4 3 23 3 2 54 47 3 41 20 25 0 0 3 42 40 23 36 31 10 67 -69 3 37 41 3 47 40 3 19 25 4 5 55 26 0 0 4 7 6 23 36 32 11 67 -68 4 2 7 4 12 5 3 43 52 4 30 19 27 0 0 4 31 21 23 36 33 12 67 -67 4 26 22 4 36 20 4 8 8 4 54 33 28 0 0 4 55 24 23 36 34 13 67 -65 4 50 25 5 0 22 4 32 13 5 18 34 29 0 0 5 19 14 23 36 35 14 68 -64 5 14 16 5 24 12 4 56 5 5 42 23 30 0 0 5 42 52 23 36 37 15 68 -63 5 37 54 5 47 50 5 19 44 6 5 59 31 0 0 6 6 17 23 36 38 16 68 -62 6 1 19 6 11 14 5 43 10 6 29 22 32 0 0 6 29 27 23 36 40 17 68 -61 6 24 30 6 34 24 6 6 23 6 52 31 33 0 0 6 52 24 23 36 41 18 68 -60 6 47 27 6 57 20 6 29 21 7 15 26 34 0 0 7 15 5 23 36 43 19 68 -59 7 10 9 7 20 1 6 52 4 7 38 6 35 0 0 7 37 31 23 36 44 20 68 -58 7 32 35 7 42 27 7 14 32 8 0 30 36 0 0 7 59 42 23 36 46 21 68 -57 7 54 46 8 4 37 7 36 44 8 22 38 37 0 0 8 21 36 23 36 48 22 68 -56 8 16 41 8 26 31 7 58 41 8 44 31 38 0 0 8 43 14 23 36 50 24 69 -55 8 38 19 8 48 8 8 20 20 9 6 6 39 0 0 9 4 34 23 36 52 25 69 -54 8 59 40 9 9 28 8 41 43 9 27 25 40 0 0 9 25 37 23 36 54 26 69 -53 9 20 44 9 30 31 9 2 48 9 48 26 41 0 0 9 46 23 23 36 57 27 69 -52 9 41 29 9 51 16 9 23 35 10 9 10 42 0 0 10 6 50 23 36 59 28 69 -51 10 1 57 10 11 43 9 44 4 10 29 35 43 0 0 10 26 58 23 37 1 29 69 -50 10 22 6 10 31 51 10 4 15 10 49 41 44 0 0 10 46 48 23 37 4 30 69 -49 10 41 56 10 51 40 10 24 7 11 9 29 45 0 0 11 6 19 23 37 6 31 70 -47 11 1 27 11 11 10 10 43 39 11 28 57 46 0 0 11 25 29 23 37 9 32 70 -46 11 20 38 11 30 21 11 2 52 11 48 6 47 0 0 11 44 20 23 37 12 33 70 -45 11 39 30 11 49 11 11 21 45 12 6 55 48 0 0 12 2 51 23 37 14 34 70 -44 11 58 1 12 7 42 11 40 18 12 25 24 49 0 0 12 21 2 23 37 17 35 70 -43 12 16 12 12 25 51 11 58 31 12 43 32 50 0 0 12 38 51 23 37 20 36 70 -42 12 34 2 12 43 41 12 16 23 13 1 20 51 0 0 12 56 20 23 37 23 37 71 -41 12 51 31 13 1 9 12 33 53 13 18 46 52 0 0 13 13 28 23 37 26 38 71 -40 13 8 39 13 18 16 12 51 3 13 35 52 53 0 0 13 30 14 23 37 29 39 71 -39 13 25 26 13 35 2 13 7 51 13 52 36 54 0 0 13 46 38 23 37 32 40 71 -38 13 41 51 13 51 26 13 24 18 14 8 58 55 0 0 14 2 41 23 37 35 41 71 -37 13 57 54 14 7 28 13 40 22 14 24 59 56 0 0 14 18 22 23 37 39 42 72 -36 14 13 35 14 23 8 13 56 5 14 40 37 57 0 0 14 33 40 23 37 42 43 72 -35 14 28 54 14 38 26 14 11 25 14 55 54 58 0 0 14 48 36 23 37 45 44 72 -34 14 43 50 14 53 22 14 26 23 15 10 48 59 0 0 15 3 9 23 37 49 45 72 -33 14 58 24 15 7 55 14 40 59 15 25 19 60 0 0 15 17 20 23 37 52 46 72 -32 15 12 35 15 22 5 14 55 11 15 39 28 61 0 0 15 31 8 23 37 56 47 73 -31 15 26 23 15 35 52 15 9 1 15 53 14 62 0 0 15 44 32 23 37 59 48 73 -30 15 39 48 15 49 17 15 22 27 16 6 37 63 0 0 15 57 34 23 38 3 49 73 -29 15 52 50 16 2 18 15 35 31 16 19 36 64 0 0 16 10 12 23 38 6 50 73 -28 16 5 29 16 14 56 15 48 11 16 32 13 65 0 0 16 22 27 23 38 10 51 73 -27 16 17 44 16 27 10 16 0 28 16 44 26 66 0 0 16 34 19 23 38 14 52 73 -26 16 29 36 16 39 1 16 12 21 16 56 16 67 0 0 16 45 46 23 38 18 53 74 -25 16 41 4 16 50 29 16 23 50 17 7 42 68 0 0 16 56 51 23 38 21 54 74 -24 16 52 9 17 1 33 16 34 56 17 18 45 69 0 0 17 7 31 23 38 25 55 74 -23 17 2 49 17 12 13 16 45 38 17 29 23 70 0 0 17 17 48 23 38 29 56 74 -22 17 13 6 17 22 29 16 55 56 17 39 38 71 0 0 17 27 40 23 38 33 57 74 -21 17 22 59 17 32 21 17 5 50 17 49 30 72 0 0 17 37 9 23 38 37 58 74 -20 17 32 28 17 41 50 17 15 20 17 58 57 73 0 0 17 46 14 23 38 41 59 74 -19 17 41 33 17 50 54 17 24 26 18 8 0 74 0 0 17 54 54 23 38 45 60 75 -18 17 50 14 17 59 34 17 33 8 18 16 39 75 0 0 18 3 10 23 38 49 61 75 -17 17 58 30 18 7 50 17 41 26 18 24 54 76 0 0 18 11 2 23 38 53 62 75 -16 18 6 23 18 15 42 17 49 19 18 32 45 77 0 0 18 18 30 23 38 57 63 75 -15 18 13 51 18 23 10 17 56 48 18 40 12 78 0 0 18 25 34 23 39 2 64 75 -14 18 20 55 18 30 13 18 3 53 18 47 14 79 0 0 18 32 13 23 39 6 65 75 -13 18 27 34 18 36 52 18 10 33 18 53 52 80 0 0 18 38 28 23 39 10 66 75 -12 18 33 49 18 43 7 18 16 49 19 0 6 81 0 0 18 44 18 23 39 14 67 75 -11 18 39 40 18 48 57 18 22 40 19 5 56 82 0 0 18 49 44 23 39 19 68 75 -10 18 45 6 18 54 23 18 28 7 19 11 21 83 0 0 18 54 46 23 39 23 69 75 -9 18 50 8 18 59 24 18 33 10 19 16 22 84 0 0 18 59 23 23 39 27 70 74 -9 18 54 45 19 4 1 18 37 47 19 20 58 85 0 0 19 3 35 23 39 32 71 74 -8 18 58 58 19 8 13 18 42 1 19 25 10 86 0 0 19 7 23 23 39 36 71 74 -7 19 2 46 19 12 1 18 45 49 19 28 57 87 0 0 19 10 47 23 39 40 72 74 -6 19 6 9 19 15 24 18 49 13 19 32 20 88 0 0 19 13 46 23 39 45 73 73 -5 19 9 8 19 18 23 18 52 13 19 35 18 89 0 0 19 16 20 23 39 49 74 73 -4 19 11 43 19 20 57 18 54 47 19 37 52 90 0 0 19 18 30 23 39 54 75 72 -3 19 13 53 19 23 7 18 56 57 19 40 2 91 0 0 19 20 15 23 39 58 76 71 -2 19 15 38 19 24 52 18 58 43 19 41 47 92 0 0 19 21 36 23 40 3 77 71 -1 19 16 58 19 26 13 19 0 4 19 43 7 Uncertainty in time = +/- 2 secs Prediction of 2012 Apr 8.0 Data for the target star ------------------------ * name: TYC 1879-00184-1 * constellation : Gemini * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 06 25 20.7971 DE: +23 03 24.435 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .015, .014 ) * V mag [mag]: 8.4 * B mag [mag]: 8.5 * Apparent position with proper motion RA(deg): 96.5327578596 DE(deg): 23.0476343448 * Equation of equinoxes (radians) : 0.000066455429412 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (299) Thora approx. diameter [km]: 17 approx. diameter ["]: .010 distance from Earth [AU]: 2.29100 * orbital information: orbit source: Preston date of fit: 2012 Apr 08 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1154 number of rejected observations: 55 time covered by the observations: 1932 Nov 30 - 2011 Oct 10 1 sigma uncertainty ellipse (major, minor, PA): 0.023, 0.012, 94° remarks: * orbital elements for (299) Thora : Mean anomaly = 33.22504434 deg Arg. of pericenter = 151.61435672 deg Long. of node = 241.55007158 deg Inclination = 1.60358956 deg Eccentricity = 0.06276904 Semimajor axis = 2.43513664 AU Perihelion dist = 2.28228546 AU Mag: H = 11.23, G = 0.15 Epoch of elements : MJD 56186.98700000 TDT (2012 Sep 16.987) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 16 299 Thora 23h 41.0m UT 8.4 6 25 20.797 23 3 24.44TYC 1879-00184-1 8.5 16.2 17 0.7 2.291 3.649 -3.62 104.7687 23.058 -176.61 2.18 23.6832 -0.00780 -0.07152 13.11967 -0.94094 -0.00539 0.00023 2000 31.4128292012 910.00000151.614357241.550072 1.6035900.06276904 2.4351366 2.282285511.4 5.00.15 RATE 2.5936960 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.028 0.018 93 2.83 0.019 0 0 1-5 056025.0020120916_0184-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 22, 03:59 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org