IOTA/IOTA-ES occultation update for (39) Laetitia / TYC 0275-00367-1 event on 2012 Oct 22, 20:39 UT Visible from E Russia Summary ------- On 2012 Oct 22 UT, the 216 km diameter asteroid (39) Laetitia will occult a 10.1 mag star in the constellation Virgo for observers along a path across E Russia. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.2 mag to 12.1 mag (the magnitude of the asteroid) for at most 5.4 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 Oct 22, 20:37 - 2012 Oct 22, 20:37 UT * geocentric midpoint of event [JD]: 2456223.36091667 * magnitude of target star: 10.1 * magnitude drop [mag]: 2.2 * estimated maximum duration [s]: 5.4 * Moon: 58 % sunlit, 133° distance * Sun: 35° distance * rough path description: E Russia The occultation path -------------------- * approximate projected width [km]: 248 * 1 sigma uncertainty interval [path widths]: +/- 0.32 * 1 sigma uncertainty interval [seconds]: +/- 1.8 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .026 +/- .025) * 1 sigma uncertainty ellipse (major, minor, PA): ( .026", .025", 91° ) * approx speed of asteroid's shadow [km/s]: 39.8971 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 0275-00367-1 by 39 Laetitia on 2012 Oct 22 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 102 0 0 48 36 14 20 37 25 0 86 -31 47 29 14 49 43 59 46 46 43 50 27 46 103 0 0 48 39 3 20 37 25 1 87 -31 47 32 5 49 46 46 46 49 35 50 30 31 104 0 0 48 41 37 20 37 25 2 87 -30 47 34 40 49 49 18 46 52 12 50 33 2 105 0 0 48 43 55 20 37 25 2 88 -29 47 37 0 49 51 34 46 54 32 50 35 17 106 0 0 48 45 57 20 37 25 3 89 -29 47 39 4 49 53 35 46 56 37 50 37 17 107 0 0 48 47 44 20 37 25 4 90 -28 47 40 52 49 55 20 46 58 26 50 39 2 108 0 0 48 49 15 20 37 25 4 90 -27 47 42 24 49 56 50 46 59 59 50 40 31 109 0 0 48 50 30 20 37 25 5 91 -27 47 43 40 49 58 5 47 1 16 50 41 44 110 0 0 48 51 30 20 37 26 5 92 -26 47 44 41 49 59 4 47 2 17 50 42 43 111 0 0 48 52 14 20 37 26 6 93 -25 47 45 25 49 59 47 47 3 2 50 43 26 112 0 0 48 52 43 20 37 26 7 93 -25 47 45 54 50 0 15 47 3 31 50 43 54 113 0 0 48 52 56 20 37 26 7 94 -24 47 46 8 50 0 28 47 3 44 50 44 6 114 0 0 48 52 53 20 37 27 8 95 -23 47 46 5 50 0 25 47 3 42 50 44 4 115 0 0 48 52 34 20 37 27 9 96 -23 47 45 46 50 0 7 47 3 23 50 43 45 116 0 0 48 52 0 20 37 27 9 96 -22 47 45 12 49 59 33 47 2 49 50 43 12 117 0 0 48 51 11 20 37 28 10 97 -22 47 44 22 49 58 44 47 1 58 50 42 23 118 0 0 48 50 5 20 37 28 11 98 -21 47 43 16 49 57 39 47 0 52 50 41 19 119 0 0 48 48 44 20 37 28 11 99 -20 47 41 54 49 56 19 46 59 29 50 39 59 120 0 0 48 47 8 20 37 29 12 99 -20 47 40 16 49 54 43 46 57 51 50 38 24 121 0 0 48 45 15 20 37 29 13 100 -19 47 38 23 49 52 52 46 55 57 50 36 34 122 0 0 48 43 7 20 37 30 13 101 -18 47 36 13 49 50 46 46 53 47 50 34 28 123 0 0 48 40 43 20 37 30 14 102 -18 47 33 48 49 48 23 46 51 20 50 32 6 124 0 0 48 38 4 20 37 31 15 103 -17 47 31 7 49 45 45 46 48 38 50 29 30 125 0 0 48 35 8 20 37 31 15 103 -16 47 28 10 49 42 52 46 45 40 50 26 37 126 0 0 48 31 57 20 37 32 16 104 -16 47 24 57 49 39 43 46 42 25 50 23 30 127 0 0 48 28 30 20 37 33 17 105 -15 47 21 27 49 36 18 46 38 55 50 20 7 128 0 0 48 24 48 20 37 33 17 106 -14 47 17 42 49 32 38 46 35 8 50 16 28 129 0 0 48 20 49 20 37 34 18 106 -14 47 13 41 49 28 42 46 31 6 50 12 34 130 0 0 48 16 35 20 37 34 19 107 -13 47 9 24 49 24 30 46 26 47 50 8 24 131 0 0 48 12 4 20 37 35 19 108 -12 47 4 51 49 20 3 46 22 12 50 3 58 132 0 0 48 7 18 20 37 36 20 109 -12 47 0 2 49 15 20 46 17 21 49 59 17 133 0 0 48 2 16 20 37 37 21 110 -11 46 54 57 49 10 21 46 12 14 49 54 20 134 0 0 47 56 58 20 37 37 21 110 -10 46 49 35 49 5 6 46 6 50 49 49 8 135 0 0 47 51 24 20 37 38 22 111 -10 46 43 58 48 59 35 46 1 11 49 43 39 136 0 0 47 45 34 20 37 39 23 112 -9 46 38 4 48 53 49 45 55 15 49 37 56 137 0 0 47 39 28 20 37 40 23 113 -8 46 31 54 48 47 47 45 49 3 49 31 56 138 0 0 47 33 5 20 37 41 24 114 -7 46 25 28 48 41 28 45 42 34 49 25 40 139 0 0 47 26 27 20 37 42 25 114 -7 46 18 46 48 34 54 45 35 50 49 19 9 140 0 0 47 19 33 20 37 43 25 115 -6 46 11 48 48 28 4 45 28 49 49 12 22 141 0 0 47 12 22 20 37 44 26 116 -5 46 4 33 48 20 58 45 21 31 49 5 18 142 0 0 47 4 56 20 37 45 27 117 -5 45 57 2 48 13 36 45 13 58 48 57 59 143 0 0 46 57 13 20 37 46 27 118 -4 45 49 15 48 5 58 45 6 8 48 50 24 144 0 0 46 49 14 20 37 47 28 119 -3 45 41 11 47 58 4 44 58 1 48 42 33 145 0 0 46 40 59 20 37 48 29 119 -3 45 32 52 47 49 54 44 49 39 48 34 26 146 0 0 46 32 28 20 37 49 29 120 -2 45 24 16 47 41 28 44 41 0 48 26 3 147 0 0 46 23 41 20 37 50 30 121 -1 45 15 23 47 32 45 44 32 4 48 17 24 148 0 0 46 14 37 20 37 51 31 122 0 45 6 15 47 23 47 44 22 52 48 8 29 Uncertainty in time = +/- 2 secs Prediction of 2012 Jul 10.0 Data for the target star ------------------------ * name: TYC 0275-00367-1 * constellation : Virgo * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 11 43 15.6271 DE: +02 57 17.396 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .025, .024 ) * V mag [mag]: 10.1 * B mag [mag]: 10.5 * Apparent position with proper motion RA(deg): 175.9786083581 DE(deg): 2.8838992828 * Equation of equinoxes (radians) : 0.000060713726209 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (39) Laetitia approx. diameter [km]: 216 approx. diameter ["]: .078 distance from Earth [AU]: 3.82300 * orbital information: orbit source: Preston date of fit: 2012 Jul 10 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 4574 number of rejected observations: 332 time covered by the observations: 1903 May 19 - 2012 May 01 1 sigma uncertainty ellipse (major, minor, PA): 0.006, 0.005, 103° remarks: * orbital elements for (39) Laetitia : Mean anomaly = 153.74768753 deg Arg. of pericenter = 208.41600759 deg Long. of node = 157.13487360 deg Inclination = 10.38192560 deg Eccentricity = 0.11455102 Semimajor axis = 2.76740287 AU Perihelion dist = 2.45039406 AU Mag: H = 6.00, G = 0.15 Epoch of elements : MJD 56222.86100000 TDT (2012 Oct 22.861) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Oct 22 39 Laetitia 20h 39.7m UT 10.1 11 43 15.627 2 57 17.40TYC 0275-00367-1 10.5 12.1 216 5.4 3.823 3.272 -16.74 -165.7932 2.960 -133.83 -11.42 20.6620 0.15803 0.46746 21.31114 -7.27607 -0.00306 0.00141 2000 153.13517820121020.00000208.416008157.134874 10.3819260.11455102 2.7674029 2.4503940 6.1 5.00.15 RATE 2.1408950 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.026 0.025 91 1.32 0.025 0 0 1-4 056118.0020121022_0367-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Aug 26, 05:00 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org