IOTA/IOTA-ES occultation update for (409) Aspasia / TYC 6131-00044-1 event on 2008 Dec 28, 23:56 UT Visible from Madagascar, Africa Summary ------- On 2008 Dec 28 UT, the 162 km diameter asteroid (409) Aspasia will occult a 10.2 mag star in the constellation Virgo for observers along a path across Madagascar, Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.5 mag to 12.6 mag (the magnitude of the asteroid) for at most 5.2 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: UCAC. The event at a glimpse ---------------------- * Rank: 99 * date and approx. time of event: 2008 Dec 28, 23:52 - 2008 Dec 28, 23:54 UT * magnitude of target star: 10.2 * magnitude drop [mag]: 2.5 * estimated maximum duration [s]: 5.2 * Moon: 2 % sunlit, 82° distance * Sun: 65° distance * rough path description: Madagascar, Africa The occultation path -------------------- * approximate projected width [km]: 182 * 1 sigma uncertainty interval [path widths]: +/- 0.25 * 1 sigma uncertainty interval [seconds]: +/- 1.2 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .020 +/- .021) * 1 sigma uncertainty ellipse (major, minor, PA): ( .021", .020", 1° ) * approx speed of asteroid's shadow [km/s]: 30.9689 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6131-00044-1 by 409 Aspasia on 2008 Dec 28 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 20 0 0 - 5 23 53 23 52 59 0 110 -57 - 6 16 57 - 4 31 16 - 6 43 40 - 4 5 8 21 0 0 - 5 46 18 23 52 59 2 110 -56 - 6 39 32 - 4 53 32 - 7 6 19 - 4 27 19 22 0 0 - 6 9 15 23 52 59 3 110 -55 - 7 2 39 - 5 16 19 - 7 29 31 - 4 50 1 23 0 0 - 6 32 44 23 52 59 4 110 -54 - 7 26 17 - 5 39 38 - 7 53 15 - 5 13 15 24 0 0 - 6 56 43 23 52 59 5 110 -53 - 7 50 27 - 6 3 28 - 8 17 30 - 5 37 0 25 0 0 - 7 21 14 23 53 0 6 109 -52 - 8 15 8 - 6 27 48 - 8 42 16 - 6 1 15 26 0 0 - 7 46 15 23 53 0 7 109 -51 - 8 40 20 - 6 52 39 - 9 7 33 - 6 26 1 27 0 0 - 8 11 47 23 53 1 8 109 -50 - 9 6 2 - 7 18 0 - 9 33 20 - 6 51 17 28 0 0 - 8 37 48 23 53 1 9 109 -49 - 9 32 13 - 7 43 51 - 9 59 38 - 7 17 3 29 0 0 - 9 4 18 23 53 2 10 109 -48 - 9 58 54 - 8 10 11 -10 26 24 - 7 43 18 30 0 0 - 9 31 17 23 53 3 11 109 -48 -10 26 5 - 8 37 0 -10 53 40 - 8 10 2 31 0 0 - 9 58 45 23 53 4 12 108 -47 -10 53 43 - 9 4 17 -11 21 24 - 8 37 14 32 0 0 -10 26 40 23 53 5 13 108 -46 -11 21 49 - 9 32 2 -11 49 36 - 9 4 53 33 0 0 -10 55 3 23 53 6 14 108 -45 -11 50 23 -10 0 14 -12 18 15 - 9 33 0 34 0 0 -11 23 52 23 53 7 16 108 -44 -12 19 23 -10 28 53 -12 47 21 -10 1 34 35 0 0 -11 53 8 23 53 8 17 108 -42 -12 48 49 -10 57 57 -13 16 52 -10 30 33 36 0 0 -12 22 49 23 53 10 18 107 -41 -13 18 41 -11 27 28 -13 46 50 -10 59 58 37 0 0 -12 52 54 23 53 11 19 107 -40 -13 48 58 -11 57 23 -14 17 12 -11 29 48 38 0 0 -13 23 24 23 53 13 20 107 -39 -14 19 38 -12 27 42 -14 47 58 -12 0 2 39 0 0 -13 54 17 23 53 14 21 106 -38 -14 50 41 -12 58 24 -15 19 7 -12 30 40 40 0 0 -14 25 32 23 53 16 22 106 -37 -15 22 7 -13 29 29 -15 50 38 -13 1 39 41 0 0 -14 57 9 23 53 17 23 106 -36 -15 53 55 -14 0 56 -16 22 31 -13 33 1 42 0 0 -15 29 7 23 53 19 24 105 -35 -16 26 3 -14 32 43 -16 54 44 -14 4 44 43 0 0 -16 1 24 23 53 21 25 105 -34 -16 58 31 -15 4 51 -17 27 17 -14 36 47 44 0 0 -16 34 1 23 53 23 26 104 -33 -17 31 18 -15 37 18 -18 0 9 -15 9 9 45 0 0 -17 6 56 23 53 25 27 104 -32 -18 4 22 -16 10 3 -18 33 19 -15 41 49 46 0 0 -17 40 7 23 53 27 28 104 -31 -18 37 44 -16 43 5 -19 6 45 -16 14 47 47 0 0 -18 13 35 23 53 29 30 103 -30 -19 11 21 -17 16 24 -19 40 27 -16 48 1 48 0 0 -18 47 18 23 53 32 31 103 -29 -19 45 13 -17 49 58 -20 14 24 -17 21 30 49 0 0 -19 21 15 23 53 34 32 102 -28 -20 19 19 -18 23 46 -20 48 35 -17 55 14 50 0 0 -19 55 25 23 53 36 33 101 -26 -20 53 37 -18 57 47 -21 22 58 -18 29 11 51 0 0 -20 29 46 23 53 39 34 101 -25 -21 28 7 -19 32 1 -21 57 32 -19 3 21 52 0 0 -21 4 18 23 53 41 35 100 -24 -22 2 48 -20 6 25 -22 32 16 -19 37 41 53 0 0 -21 39 0 23 53 44 36 100 -23 -22 37 37 -20 40 59 -23 7 10 -20 12 11 54 0 0 -22 13 50 23 53 47 37 99 -22 -23 12 35 -21 15 42 -23 42 11 -20 46 51 55 0 0 -22 48 47 23 53 49 38 98 -21 -23 47 39 -21 50 32 -24 17 19 -21 21 37 56 0 0 -23 23 50 23 53 52 39 97 -20 -24 22 49 -22 25 29 -24 52 32 -21 56 31 57 0 0 -23 58 58 23 53 55 40 97 -19 -24 58 3 -23 0 30 -25 27 50 -22 31 29 58 0 0 -24 34 9 23 53 58 41 96 -18 -25 33 20 -23 35 36 -26 3 10 -23 6 32 59 0 0 -25 9 23 23 54 1 42 95 -17 -26 8 39 -24 10 44 -26 38 32 -23 41 38 60 0 0 -25 44 38 23 54 4 43 94 -16 -26 43 59 -24 45 54 -27 13 54 -24 16 45 61 0 0 -26 19 52 23 54 7 44 93 -14 -27 19 18 -25 21 4 -27 49 15 -24 51 53 62 0 0 -26 55 5 23 54 10 45 92 -13 -27 54 35 -25 56 13 -28 24 34 -25 27 0 63 0 0 -27 30 15 23 54 13 46 91 -12 -28 29 49 -26 31 19 -28 59 50 -26 2 5 64 0 0 -28 5 22 23 54 16 46 90 -11 -29 4 58 -27 6 23 -29 35 1 -26 37 7 65 0 0 -28 40 23 23 54 19 47 89 -10 -29 40 2 -27 41 22 -30 10 7 -27 12 4 66 0 0 -29 15 18 23 54 22 48 88 -9 -30 14 59 -28 16 15 -30 45 5 -27 46 56 67 0 0 -29 50 6 23 54 25 49 87 -8 -30 49 49 -28 51 0 -31 19 55 -28 21 41 68 0 0 -30 24 45 23 54 29 50 85 -7 -31 24 29 -29 25 38 -31 54 36 -28 56 19 69 0 0 -30 59 14 23 54 32 51 84 -6 -31 58 59 -30 0 7 -32 29 6 -29 30 47 70 0 0 -31 33 32 23 54 35 51 83 -5 -32 33 17 -30 34 25 -33 3 24 -30 5 5 71 0 0 -32 7 38 23 54 38 52 81 -4 -33 7 23 -31 8 32 -33 37 30 -30 39 12 72 0 0 -32 41 32 23 54 42 53 80 -3 -33 41 15 -31 42 26 -34 11 22 -31 13 6 73 0 0 -33 15 11 23 54 45 54 78 -2 -34 14 53 -32 16 6 -34 44 59 -31 46 47 74 0 0 -33 48 35 23 54 48 54 77 -1 -34 48 15 -32 49 32 -35 18 20 -32 20 14 Uncertainty in time = +/- 1 secs [Prediction of 2008 Nov 14.0] Data for the target star ------------------------ * name: TYC 6131-00044-1 * constellation : Virgo * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 13 49 28.7711 DE: -19 52 29.048 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .018, .019 ) * V mag [mag]: 10.2 * B mag [mag]: 10.6 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (409) Aspasia approx. diameter [km]: 162 approx. diameter ["]: .083 distance from Earth [AU]: 2.68400 * orbital information: orbit source: Preston date of fit: 2008 Nov 13 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1187 number of rejected observations: 140 time covered by the observations: 1902 Jul 07 - 2008 May 14 1 sigma uncertainty ellipse (major, minor, PA): 0.009, 0.007, 98° remarks: * orbital elements for (409) Aspasia : Mean anomaly = 320.50834956 deg Arg. of pericenter = 352.90586475 deg Long. of node = 242.35164922 deg Inclination = 11.24318534 deg Eccentricity = 0.07035236 Semimajor axis = 2.57610667 AU Perihelion dist = 2.39487149 AU Mag: H = 7.65, G = 0.29 Epoch of elements : MJD 54828.99700000 TDT (2008 Dec 28.997) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Dec 28 409 Aspasia 23h 56.0m UT 10.2 13 49 28.771-19 52 29.05TYC 6131-00044-1 10.6 12.6 162 5.2 2.684 3.771 -21.22 110.5423 -19.869 -178.51 -23.22 23.9338 -0.16953 -0.42570 16.23583 -6.47599 -0.00508 0.00157 2000 318.36370220081220.00000352.905865242.351649 11.2431850.07035236 2.5761067 2.3948715 7.6 5.00.29 RATE 2.3837370 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.021 0.020 1 1.25 0.021 0 54784.5020081228_0044-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Nov 14, 06:54 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org