IOTA/IOTA-ES occultation update for (65) Cybele / HIP 48161 event on 2012 Sep 27, 12:39 UT Visible from Mexico (twilight) Summary ------- On 2012 Sep 27 UT, the 301 km diameter asteroid (65) Cybele will occult a 8.4 mag star in the constellation Leo for observers along a path across Mexico (twilight). In the case of an occultation, the combined light of the asteroid and the star will drop by 5.0 mag to 13.4 mag (the magnitude of the asteroid) for at most 7.9 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: 100 * date and approx. time of event: 2012 Sep 27, 12:36 - 2012 Sep 27, 12:37 UT * geocentric midpoint of event [JD]: 2456198.0275875 * magnitude of target star: 8.4 * magnitude drop [mag]: 5.0 * estimated maximum duration [s]: 7.9 * Moon: 93 % sunlit, 170° distance * Sun: 39° distance * rough path description: Mexico (twilight) The occultation path -------------------- * approximate projected width [km]: 301 * 1 sigma uncertainty interval [path widths]: +/- 0.12 * 1 sigma uncertainty interval [seconds]: +/- 1.7 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .022 +/- .010) * 1 sigma uncertainty ellipse (major, minor, PA): ( .022", .010", 92° ) * approx speed of asteroid's shadow [km/s]: 37.8918 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 48161 by 65 Cybele on 2012 Sep 27 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 -142 0 0 18 48 47 12 36 56 1 77 -39 17 25 12 20 12 21 17 5 9 20 32 25 -141 0 0 19 1 17 12 36 56 2 78 -38 17 37 49 20 24 46 17 17 47 20 44 48 -140 0 0 19 13 27 12 36 56 3 78 -37 17 50 5 20 36 50 17 30 4 20 56 51 -139 0 0 19 25 16 12 36 56 4 78 -36 18 2 0 20 48 33 17 42 0 21 8 33 -138 0 0 19 36 44 12 36 56 4 79 -35 18 13 34 20 59 55 17 53 36 21 19 54 -137 0 0 19 47 51 12 36 56 5 79 -34 18 24 47 21 10 57 18 4 50 21 30 54 -136 0 0 19 58 38 12 36 57 6 79 -33 18 35 38 21 21 37 18 15 43 21 41 33 -135 0 0 20 9 3 12 36 57 7 80 -32 18 46 9 21 31 57 18 26 15 21 51 51 -134 0 0 20 19 6 12 36 57 8 80 -31 18 56 18 21 41 55 18 36 25 22 1 48 -133 0 0 20 28 49 12 36 58 9 81 -30 19 6 5 21 51 32 18 46 14 22 11 24 -132 0 0 20 38 9 12 36 58 10 81 -29 19 15 31 22 0 48 18 55 41 22 20 39 -131 0 0 20 47 9 12 36 59 11 81 -28 19 24 35 22 9 43 19 4 46 22 29 32 -130 0 0 20 55 47 12 36 59 12 82 -27 19 33 18 22 18 16 19 13 30 22 38 4 -129 0 0 21 4 3 12 37 0 13 82 -26 19 41 39 22 26 28 19 21 52 22 46 15 -128 0 0 21 11 58 12 37 1 14 82 -25 19 49 38 22 34 18 19 29 52 22 54 4 -127 0 0 21 19 31 12 37 1 15 83 -24 19 57 15 22 41 47 19 37 30 23 1 32 -126 0 0 21 26 42 12 37 2 16 83 -23 20 4 31 22 48 55 19 44 47 23 8 39 -125 0 0 21 33 32 12 37 3 17 83 -22 20 11 24 22 55 40 19 51 41 23 15 23 -124 0 0 21 40 0 12 37 4 18 84 -22 20 17 55 23 2 4 19 58 13 23 21 47 -123 0 0 21 46 6 12 37 5 19 84 -21 20 24 5 23 8 7 20 4 23 23 27 48 -122 0 0 21 51 50 12 37 5 20 84 -20 20 29 52 23 13 47 20 10 12 23 33 28 -121 0 0 21 57 12 12 37 6 21 85 -19 20 35 17 23 19 6 20 15 37 23 38 46 -120 0 0 22 2 12 12 37 7 22 85 -18 20 40 20 23 24 4 20 20 41 23 43 43 -119 0 0 22 6 50 12 37 8 22 86 -17 20 45 1 23 28 39 20 25 23 23 48 18 -118 0 0 22 11 6 12 37 9 23 86 -16 20 49 20 23 32 53 20 29 42 23 52 31 -117 0 0 22 15 0 12 37 11 24 86 -15 20 53 16 23 36 44 20 33 39 23 56 22 -116 0 0 22 18 32 12 37 12 25 87 -14 20 56 50 23 40 14 20 37 13 23 59 51 -115 0 0 22 21 42 12 37 13 26 87 -13 21 0 2 23 43 23 20 40 25 24 2 59 -114 0 0 22 24 30 12 37 14 27 88 -12 21 2 51 23 46 9 20 43 15 24 5 45 -113 0 0 22 26 56 12 37 15 28 88 -11 21 5 18 23 48 33 20 45 43 24 8 9 -112 0 0 22 28 59 12 37 17 29 88 -10 21 7 23 23 50 35 20 47 48 24 10 11 -111 0 0 22 30 41 12 37 18 30 89 -9 21 9 6 23 52 16 20 49 31 24 11 51 -110 0 0 22 32 0 12 37 19 31 89 -8 21 10 26 23 53 34 20 50 51 24 13 9 -109 0 0 22 32 57 12 37 21 32 89 -8 21 11 23 23 54 31 20 51 49 24 14 6 -108 0 0 22 33 32 12 37 22 33 90 -7 21 11 59 23 55 5 20 52 24 24 14 40 -107 0 0 22 33 45 12 37 24 34 90 -6 21 12 11 23 55 18 20 52 37 24 14 53 -106 0 0 22 33 35 12 37 25 35 91 -5 21 12 2 23 55 9 20 52 27 24 14 43 -105 0 0 22 33 3 12 37 27 35 91 -4 21 11 30 23 54 37 20 51 55 24 14 12 -104 0 0 22 32 9 12 37 28 36 91 -3 21 10 35 23 53 44 20 51 0 24 13 19 -103 0 0 22 30 53 12 37 30 37 92 -2 21 9 18 23 52 28 20 49 43 24 12 3 -102 0 0 22 29 15 12 37 32 38 92 -1 21 7 39 23 50 51 20 48 4 24 10 26 -101 0 0 22 27 14 12 37 34 39 93 0 21 5 37 23 48 51 20 46 1 24 8 27 Uncertainty in time = +/- 2 secs Prediction of 2012 Aug 7.0 Data for the target star ------------------------ * name: HIP 48161 * constellation : Leo * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 09 48 59.8588 DE: +12 05 47.406 * position source: mpos:HIP2 pm:HIP2 plx:HIP2 * standard error: RA,DE ["]: ( .020, .009 ) * V mag [mag]: 8.4 * B mag [mag]: 8.9 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (65) Cybele approx. diameter [km]: 301 approx. diameter ["]: .096 distance from Earth [AU]: 4.32000 * orbital information: orbit source: Preston date of fit: 2012 Aug 06 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1729 number of rejected observations: 128 time covered by the observations: 1903 Dec 14 - 2012 Mar 15 1 sigma uncertainty ellipse (major, minor, PA): 0.008, 0.005, 106° remarks: * orbital elements for (65) Cybele : Mean anomaly = 247.89523058 deg Arg. of pericenter = 102.63560541 deg Long. of node = 155.65036826 deg Inclination = 3.56299605 deg Eccentricity = 0.10999841 Semimajor axis = 3.42538575 AU Perihelion dist = 3.04859878 AU Mag: H = 6.72, G = 0.01 Epoch of elements : MJD 56197.52800000 TDT (2012 Sep 27.528) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 27 65 Cybele 12h 39.7m UT 8.4 9 48 59.859 12 5 47.41HIP 48161 8.9 13.4 301 7.9 4.320 2.813 -13.93 -49.3905 12.100 -12.22 -1.91 12.6621 0.00024 0.00627 20.26392 -6.83991 -0.00353 0.00116 2000 246.7248712012 920.00000102.635605155.650368 3.5629960.10999841 3.4253858 3.0485988 6.6 5.00.01 RATE 1.5546760 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.022 0.010 92 1.12 0.011 0 0-2-4 056146.0020120927__48161 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Aug 06, 21:06 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org