IOTA/IOTA-ES occultation update for (87) Sylvia / 2UCAC 40154575 event on 2012 Sep 17, 09:37 UT Visible from SE USA, Mexico Summary ------- On 2012 Sep 17 UT, the 263 km diameter asteroid (87) Sylvia will occult a 12.4 mag star in the constellation Gemini for observers along a path across SE USA, Mexico. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.2 mag to 13.2 mag (the magnitude of the asteroid) for at most 15.3 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: 99 * date and approx. time of event: 2012 Sep 17, 09:31 - 2012 Sep 17, 09:37 UT * geocentric midpoint of event [JD]: 2456187.9013625 * magnitude of target star: 12.4 * magnitude drop [mag]: 1.2 * estimated maximum duration [s]: 15.3 * Moon: 2 % sunlit, 102° distance * Sun: 84° distance * rough path description: SE USA, Mexico Additional comments ------------------- 6" double star The occultation path -------------------- * approximate projected width [km]: 269 * 1 sigma uncertainty interval [path widths]: +/- 0.28 * 1 sigma uncertainty interval [seconds]: +/- 4.1 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .030 +/- .029) * 1 sigma uncertainty ellipse (major, minor, PA): ( .030", .029", 89° ) * approx speed of asteroid's shadow [km/s]: 17.1994 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 40154575 by 87 Sylvia on 2012 Sep 17 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 -140 0 0 1 54 18 9 31 56 0 66 -84 .. .. .. 3 14 21 .. .. .. 3 59 23 -139 0 0 2 20 45 9 31 56 1 66 -83 1 1 2 3 40 55 0 16 35 4 26 2 -138 0 0 2 47 27 9 31 56 2 67 -82 1 27 37 4 7 45 0 43 5 4 52 56 -137 0 0 3 14 24 9 31 57 3 67 -81 1 54 26 4 34 49 1 9 50 5 20 5 -136 0 0 3 41 34 9 31 57 4 67 -80 2 21 29 5 2 7 1 36 50 5 47 26 -135 0 0 4 8 58 9 31 58 6 67 -79 2 48 46 5 29 37 2 4 2 6 15 1 -134 0 0 4 36 34 9 31 59 7 67 -78 3 16 15 5 57 20 2 31 28 6 42 48 -133 0 0 5 4 22 9 31 59 8 67 -77 3 43 57 6 25 15 2 59 6 7 10 46 -132 0 0 5 32 21 9 32 1 9 67 -76 4 11 50 6 53 20 3 26 56 7 38 55 -131 0 0 6 0 30 9 32 2 10 67 -74 4 39 53 7 21 36 3 54 56 8 7 14 -130 0 0 6 28 50 9 32 3 11 67 -73 5 8 7 7 50 1 4 23 6 8 35 42 -129 0 0 6 57 18 9 32 5 12 67 -72 5 36 30 8 18 34 4 51 26 9 4 19 -128 0 0 7 25 54 9 32 6 13 67 -71 6 5 1 8 47 16 5 19 55 9 33 3 -127 0 0 7 54 38 9 32 8 14 68 -70 6 33 41 9 16 4 5 48 32 10 1 54 -126 0 0 8 23 29 9 32 10 15 68 -69 7 2 27 9 45 0 6 17 16 10 30 52 -125 0 0 8 52 26 9 32 12 17 68 -68 7 31 20 10 14 0 6 46 6 10 59 55 -124 0 0 9 21 27 9 32 14 18 68 -67 8 0 18 10 43 6 7 15 2 11 29 2 -123 0 0 9 50 33 9 32 16 19 68 -66 8 29 20 11 12 15 7 44 3 11 58 14 -122 0 0 10 19 43 9 32 19 20 69 -64 8 58 27 11 41 28 8 13 8 12 27 28 -121 0 0 10 48 55 9 32 21 21 69 -63 9 27 37 12 10 42 8 42 16 12 56 44 -120 0 0 11 18 9 9 32 24 22 69 -62 9 56 49 12 39 59 9 11 27 13 26 2 -119 0 0 11 47 24 9 32 27 23 69 -61 10 26 2 13 9 16 9 40 39 13 55 20 -118 0 0 12 16 40 9 32 30 24 69 -60 10 55 16 13 38 32 10 9 52 14 24 37 -117 0 0 12 45 55 9 32 33 25 70 -59 11 24 29 14 7 48 10 39 5 14 53 54 -116 0 0 13 15 8 9 32 36 26 70 -58 11 53 42 14 37 2 11 8 17 15 23 8 -115 0 0 13 44 19 9 32 39 28 70 -57 12 22 53 15 6 13 11 37 28 15 52 19 -114 0 0 14 13 27 9 32 43 29 71 -56 12 52 1 15 35 21 12 6 36 16 21 27 -113 0 0 14 42 31 9 32 46 30 71 -55 13 21 6 16 4 25 12 35 41 16 50 30 -112 0 0 15 11 30 9 32 50 31 71 -53 13 50 6 16 33 23 13 4 42 17 19 28 -111 0 0 15 40 24 9 32 54 32 72 -52 14 19 1 17 2 16 13 33 38 17 48 20 -110 0 0 16 9 11 9 32 57 33 72 -51 14 47 50 17 31 1 14 2 28 18 17 4 -109 0 0 16 37 52 9 33 1 34 72 -50 15 16 33 17 59 39 14 31 11 18 45 41 -108 0 0 17 6 24 9 33 5 35 73 -49 15 45 8 18 28 9 14 59 48 19 14 10 -107 0 0 17 34 48 9 33 10 36 73 -48 16 13 34 18 56 30 15 28 16 19 42 29 -106 0 0 18 3 3 9 33 14 37 74 -47 16 41 52 19 24 41 15 56 36 20 10 38 -105 0 0 18 31 7 9 33 18 38 74 -46 17 10 0 19 52 42 16 24 46 20 38 36 -104 0 0 18 59 0 9 33 23 39 75 -45 17 37 58 20 20 31 16 52 45 21 6 23 -103 0 0 19 26 42 9 33 27 40 75 -44 18 5 44 20 48 8 17 20 34 21 33 58 -102 0 0 19 54 12 9 33 32 41 76 -43 18 33 18 21 15 33 17 48 11 22 1 20 -101 0 0 20 21 29 9 33 37 42 76 -42 19 0 40 21 42 45 18 15 35 22 28 29 -100 0 0 20 48 32 9 33 41 43 77 -41 19 27 48 22 9 42 18 42 47 22 55 23 - 99 0 0 21 15 21 9 33 46 45 77 -40 19 54 43 22 36 25 19 9 45 23 22 3 - 98 0 0 21 41 55 9 33 51 46 78 -38 20 21 23 23 2 53 19 36 28 23 48 27 - 97 0 0 22 8 13 9 33 56 47 78 -37 20 47 48 23 29 5 20 2 57 24 14 35 - 96 0 0 22 34 16 9 34 1 48 79 -36 21 13 58 23 55 1 20 29 10 24 40 27 - 95 0 0 23 0 2 9 34 6 49 80 -35 21 39 51 24 20 40 20 55 7 25 6 2 - 94 0 0 23 25 31 9 34 11 50 81 -34 22 5 27 24 46 2 21 20 47 25 31 20 - 93 0 0 23 50 43 9 34 17 51 81 -33 22 30 46 25 11 6 21 46 10 25 56 20 - 92 0 0 24 15 36 9 34 22 52 82 -32 22 55 47 25 35 52 22 11 15 26 21 1 - 91 0 0 24 40 11 9 34 27 52 83 -31 23 20 30 26 0 18 22 36 2 26 45 23 - 90 0 0 25 4 27 9 34 32 53 84 -30 23 44 54 26 24 26 23 0 31 27 9 26 - 89 0 0 25 28 24 9 34 38 54 84 -29 24 8 59 26 48 14 23 24 40 27 33 9 - 88 0 0 25 52 0 9 34 43 55 85 -28 24 32 44 27 11 42 23 48 30 27 56 32 - 87 0 0 26 15 17 9 34 49 56 86 -27 24 56 9 27 34 50 24 12 0 28 19 35 - 86 0 0 26 38 13 9 34 54 57 87 -26 25 19 14 27 57 37 24 35 10 28 42 17 - 85 0 0 27 0 48 9 35 0 58 88 -25 25 41 58 28 20 3 24 57 59 29 4 37 - 84 0 0 27 23 2 9 35 5 59 89 -24 26 4 21 28 42 7 25 20 27 29 26 37 - 83 0 0 27 44 54 9 35 11 60 90 -23 26 26 23 29 3 51 25 42 34 29 48 15 - 82 0 0 28 6 25 9 35 17 61 91 -22 26 48 3 29 25 12 26 4 19 30 9 30 - 81 0 0 28 27 34 9 35 22 62 93 -21 27 9 21 29 46 11 26 25 43 30 30 24 - 80 0 0 28 48 20 9 35 28 63 94 -20 27 30 17 30 6 48 26 46 44 30 50 55 - 79 0 0 29 8 44 9 35 33 64 95 -20 27 50 51 30 27 2 27 7 23 31 11 4 - 78 0 0 29 28 46 9 35 39 64 96 -19 28 11 2 30 46 54 27 27 39 31 30 50 - 77 0 0 29 48 24 9 35 45 65 98 -18 28 30 50 31 6 23 27 47 32 31 50 14 - 76 0 0 30 7 40 9 35 51 66 99 -17 28 50 15 31 25 28 28 7 3 32 9 14 - 75 0 0 30 26 32 9 35 56 67 101 -16 29 9 17 31 44 11 28 26 10 32 27 51 - 74 0 0 30 45 1 9 36 2 68 103 -15 29 27 56 32 2 30 28 44 54 32 46 4 - 73 0 0 31 3 7 9 36 8 68 104 -14 29 46 11 32 20 26 29 3 15 33 3 55 - 72 0 0 31 20 49 9 36 13 69 106 -13 30 4 2 32 37 58 29 21 12 33 21 22 - 71 0 0 31 38 7 9 36 19 70 108 -12 30 21 30 32 55 7 29 38 45 33 38 25 - 70 0 0 31 55 2 9 36 25 71 110 -11 30 38 35 33 11 52 29 55 54 33 55 5 - 69 0 0 32 11 33 9 36 30 71 113 -10 30 55 15 33 28 14 30 12 40 34 11 21 - 68 0 0 32 27 40 9 36 36 72 115 -9 31 11 31 33 44 11 30 29 2 34 27 13 - 67 0 0 32 43 24 9 36 42 73 117 -8 31 27 24 33 59 45 30 44 59 34 42 42 - 66 0 0 32 58 43 9 36 48 73 120 -8 31 42 52 34 14 56 31 0 33 34 57 47 - 65 0 0 33 13 38 9 36 53 74 123 -7 31 57 57 34 29 42 31 15 42 35 12 28 - 64 0 0 33 28 10 9 36 59 74 126 -6 32 12 37 34 44 4 31 30 27 35 26 45 - 63 0 0 33 42 17 9 37 5 75 129 -5 32 26 53 34 58 3 31 44 48 35 40 39 - 62 0 0 33 56 1 9 37 10 75 133 -4 32 40 45 35 11 38 31 58 45 35 54 8 - 61 0 0 34 9 20 9 37 16 76 136 -3 32 54 13 35 24 48 32 12 17 36 7 15 - 60 0 0 34 22 15 9 37 21 76 140 -2 33 7 17 35 37 36 32 25 25 36 19 57 - 59 0 0 34 34 47 9 37 27 77 144 -2 33 19 56 35 49 59 32 38 10 36 32 16 - 58 0 0 34 46 54 9 37 33 77 148 -1 33 32 12 36 1 58 32 50 29 36 44 11 Uncertainty in time = +/- 4 secs Prediction of 2012 Jul 22.0 Data for the target star ------------------------ * name: 2UCAC 40154575 * constellation : Gemini * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 06 01 10.0915 DE: +23 32 12.132 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .029, .029 ) * V mag [mag]: 12.4 * B mag [mag]: 0.0 * Apparent position with proper motion RA(deg): 90.4897499091 DE(deg): 23.5350817729 * Equation of equinoxes (radians) : 0.000066197824894 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (87) Sylvia approx. diameter [km]: 263 approx. diameter ["]: .105 distance from Earth [AU]: 3.44800 * orbital information: orbit source: Preston date of fit: 2012 Jul 21 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 2200 number of rejected observations: 103 time covered by the observations: 1909 Apr 21 - 2012 Feb 02 1 sigma uncertainty ellipse (major, minor, PA): 0.010, 0.006, 78° remarks: * orbital elements for (87) Sylvia : Mean anomaly = 84.73588908 deg Arg. of pericenter = 265.78690855 deg Long. of node = 73.14296629 deg Inclination = 10.88572421 deg Eccentricity = 0.08712495 Semimajor axis = 3.49815493 AU Perihelion dist = 3.19337835 AU Mag: H = 6.70, G = 0.15 Epoch of elements : MJD 56187.40100000 TDT (2012 Sep 17.401) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 17 87 Sylvia 9h 38.0m UT 12.4 6 1 10.092 23 32 12.132UCAC 40154575 0.0 13.2 263 15.3 3.448 1.772 4.33 -50.9260 23.536 34.11 2.02 9.6327 -0.03906 0.20627 9.55822 1.69760 -0.00583 0.00002 2000 83.6209892012 910.00000265.786909 73.142966 10.8857240.08712495 3.4981549 3.1933784 6.9 5.00.15 RATE 1.5064180 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.030 0.029 89 1.28 0.029 2 7 706 18 1356 0-5 2 056130.0020120917_154575 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 22, 04:01 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org