IOTA/IOTA-ES occultation update for (987) Wallia / TYC 2421-00398-1 event on 2012 Sep 11, 04:35 UT Visible from Europe Summary ------- On 2012 Sep 11 UT, the 52 km diameter asteroid (987) Wallia will occult a 11.1 mag star in the constellation Auriga for observers along a path across Europe. In the case of an occultation, the combined light of the asteroid and the star will drop by 4.1 mag to 15.2 mag (the magnitude of the asteroid) for at most 2.3 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: 47 * date and approx. time of event: 2012 Sep 11, 04:30 - 2012 Sep 11, 04:33 UT * geocentric midpoint of event [JD]: 2456181.69099583 * magnitude of target star: 11.1 * magnitude drop [mag]: 4.1 * estimated maximum duration [s]: 2.3 * Moon: 26 % sunlit, 17° distance * Sun: 73° distance * rough path description: Europe The occultation path -------------------- * approximate projected width [km]: 54 * 1 sigma uncertainty interval [path widths]: +/- 1.39 * 1 sigma uncertainty interval [seconds]: +/- 2.8 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .032 +/- .031) * 1 sigma uncertainty ellipse (major, minor, PA): ( .032", .031", 93° ) * approx speed of asteroid's shadow [km/s]: 22.7850 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 2421-00398-1 by 987 Wallia on 2012 Sep 11 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 - 58 0 0 11 9 55 4 30 33 0 58 -71 10 52 39 11 27 12 .. .. .. 12 15 25 - 57 0 0 11 46 41 4 30 33 2 59 -70 11 29 23 12 3 59 10 41 29 12 52 17 - 56 0 0 12 23 33 4 30 33 3 59 -69 12 6 14 12 40 53 11 18 16 13 29 15 - 55 0 0 13 0 30 4 30 34 4 59 -68 12 43 10 13 17 52 11 55 9 14 6 17 - 54 0 0 13 37 31 4 30 34 5 59 -67 13 20 10 13 54 54 12 32 5 14 43 22 - 53 0 0 14 14 35 4 30 35 6 59 -66 13 57 13 14 31 59 13 9 5 15 20 30 - 52 0 0 14 51 40 4 30 35 7 60 -65 14 34 17 15 9 5 13 46 7 15 57 39 - 51 0 0 15 28 46 4 30 36 8 60 -64 15 11 22 15 46 11 14 23 10 16 34 47 - 50 0 0 16 5 50 4 30 37 10 60 -63 15 48 25 16 23 16 15 0 11 17 11 54 - 49 0 0 16 42 52 4 30 38 11 61 -61 16 25 27 17 0 18 15 37 11 17 48 57 - 48 0 0 17 19 50 4 30 39 12 61 -60 17 2 25 17 37 17 16 14 8 18 25 57 - 47 0 0 17 56 43 4 30 40 13 61 -59 17 39 18 18 14 10 16 51 1 19 2 51 - 46 0 0 18 33 31 4 30 42 14 62 -58 18 16 5 18 50 58 17 27 48 19 39 39 - 45 0 0 19 10 11 4 30 43 15 62 -57 18 52 45 19 27 38 18 4 28 20 16 19 - 44 0 0 19 46 42 4 30 45 16 62 -56 19 29 17 20 4 9 18 41 0 20 52 50 - 43 0 0 20 23 4 4 30 47 18 63 -55 20 5 39 20 40 31 19 17 23 21 29 10 - 42 0 0 20 59 15 4 30 48 19 63 -54 20 41 51 21 16 41 19 53 36 22 5 20 - 41 0 0 21 35 14 4 30 50 20 63 -53 21 17 50 21 52 40 20 29 37 22 41 17 - 40 0 0 22 11 0 4 30 52 21 64 -51 21 53 37 22 28 25 21 5 26 23 17 0 - 39 0 0 22 46 32 4 30 54 22 64 -50 22 29 10 23 3 56 21 41 1 23 52 28 - 38 0 0 23 21 49 4 30 56 23 65 -49 23 4 28 23 39 12 22 16 22 24 27 41 - 37 0 0 23 56 50 4 30 59 24 65 -48 23 39 29 24 14 12 22 51 27 25 2 37 - 36 0 0 24 31 33 4 31 1 25 66 -47 24 14 14 24 48 54 23 26 15 25 37 16 - 35 0 0 25 5 58 4 31 3 26 66 -46 24 48 40 25 23 17 24 0 45 26 11 36 - 34 0 0 25 40 4 4 31 6 27 67 -45 25 22 48 25 57 22 24 34 57 26 45 36 - 33 0 0 26 13 50 4 31 8 28 67 -44 25 56 35 26 31 6 25 8 49 27 19 15 - 32 0 0 26 47 15 4 31 11 29 68 -43 26 30 2 27 4 29 25 42 20 27 52 34 - 31 0 0 27 20 18 4 31 13 30 68 -42 27 3 8 27 37 31 26 15 31 28 25 30 - 30 0 0 27 52 59 4 31 16 31 69 -41 27 35 51 28 10 10 26 48 19 28 58 4 - 29 0 0 28 25 17 4 31 19 33 69 -40 28 8 10 28 42 26 27 20 45 29 30 14 - 28 0 0 28 57 11 4 31 22 34 70 -39 28 40 7 29 14 17 27 52 47 30 1 59 - 27 0 0 29 28 41 4 31 25 35 71 -38 29 11 38 29 45 45 28 24 25 30 33 20 - 26 0 0 29 59 45 4 31 28 36 71 -37 29 42 45 30 16 47 28 55 38 31 4 15 - 25 0 0 30 30 24 4 31 31 37 72 -36 30 13 26 30 47 23 29 26 26 31 34 45 - 24 0 0 31 0 36 4 31 34 38 73 -35 30 43 41 31 17 33 29 56 48 32 4 48 - 23 0 0 31 30 22 4 31 37 38 73 -34 31 13 30 31 47 16 30 26 43 32 34 24 - 22 0 0 31 59 41 4 31 40 39 74 -33 31 42 51 32 16 32 30 56 12 33 3 32 - 21 0 0 32 28 32 4 31 43 40 75 -32 32 11 45 32 45 21 31 25 14 33 32 13 - 20 0 0 32 56 56 4 31 47 41 75 -31 32 40 11 33 13 41 31 53 47 34 0 26 - 19 0 0 33 24 51 4 31 50 42 76 -30 33 8 9 33 41 34 32 21 53 34 28 10 - 18 0 0 33 52 17 4 31 53 43 77 -29 33 35 39 34 8 57 32 49 30 34 55 26 - 17 0 0 34 19 15 4 31 57 44 78 -28 34 2 39 34 35 52 33 16 39 35 22 12 - 16 0 0 34 45 44 4 32 0 45 79 -27 34 29 11 35 2 18 33 43 19 35 48 30 - 15 0 0 35 11 43 4 32 3 46 80 -26 34 55 14 35 28 14 34 9 30 36 14 18 - 14 0 0 35 37 13 4 32 7 47 80 -25 35 20 47 35 53 42 34 35 11 36 39 36 - 13 0 0 36 2 14 4 32 10 48 81 -24 35 45 50 36 18 39 35 0 23 37 4 25 - 12 0 0 36 26 45 4 32 14 49 82 -23 36 10 25 36 43 7 35 25 6 37 28 44 - 11 0 0 36 50 46 4 32 17 49 83 -22 36 34 29 37 7 5 35 49 19 37 52 34 - 10 0 0 37 14 18 4 32 21 50 84 -21 36 58 3 37 30 33 36 13 2 38 15 53 - 9 0 0 37 37 19 4 32 24 51 85 -20 37 21 8 37 53 32 36 36 15 38 38 43 - 8 0 0 37 59 51 4 32 28 52 86 -20 37 43 43 38 16 1 36 58 59 39 1 3 - 7 0 0 38 21 53 4 32 31 53 87 -19 38 5 48 38 38 0 37 21 12 39 22 53 - 6 0 0 38 43 25 4 32 35 54 88 -18 38 27 24 38 59 29 37 42 56 39 44 14 - 5 0 0 39 4 28 4 32 38 54 89 -17 38 48 29 39 20 28 38 4 10 40 5 5 - 4 0 0 39 25 1 4 32 42 55 90 -16 39 9 5 39 40 58 38 24 55 40 25 26 - 3 0 0 39 45 4 4 32 45 56 92 -15 39 29 11 40 0 58 38 45 9 40 45 17 - 2 0 0 40 4 38 4 32 49 57 93 -14 39 48 48 40 20 29 39 4 54 41 4 40 - 1 0 0 40 23 42 4 32 53 57 94 -14 40 7 55 40 39 30 39 24 10 41 23 33 0 0 0 40 42 17 4 32 56 58 95 -13 40 26 33 40 58 2 39 42 56 41 41 56 1 0 0 41 0 23 4 33 0 59 96 -12 40 44 42 41 16 5 40 1 13 41 59 51 2 0 0 41 18 0 4 33 3 60 98 -11 41 2 22 41 33 39 40 19 1 42 17 17 3 0 0 41 35 8 4 33 7 60 99 -10 41 19 33 41 50 45 40 36 20 42 34 14 4 0 0 41 51 48 4 33 10 61 101 -9 41 36 15 42 7 21 40 53 10 42 50 43 5 0 0 42 7 58 4 33 14 62 102 -9 41 52 29 42 23 29 41 9 31 43 6 43 6 0 0 42 23 41 4 33 18 62 103 -8 42 8 14 42 39 9 41 25 24 43 22 16 7 0 0 42 38 55 4 33 21 63 105 -7 42 23 31 42 54 21 41 40 48 43 37 20 8 0 0 42 53 42 4 33 25 64 107 -6 42 38 20 43 9 4 41 55 44 43 51 56 9 0 0 43 8 0 4 33 28 64 108 -6 42 52 41 43 23 20 42 10 12 44 6 5 10 0 0 43 21 51 4 33 32 65 110 -5 43 6 34 43 37 9 42 24 12 44 19 46 11 0 0 43 35 14 4 33 35 66 112 -4 43 20 0 43 50 29 42 37 45 44 33 0 12 0 0 43 48 10 4 33 39 66 113 -3 43 32 59 44 3 23 42 50 50 44 45 47 13 0 0 44 0 39 4 33 43 67 115 -2 43 45 30 44 15 50 43 3 27 44 58 7 14 0 0 44 12 41 4 33 46 67 117 -2 43 57 34 44 27 49 43 15 38 45 10 0 15 0 0 44 24 16 4 33 50 68 119 -1 44 9 11 44 39 22 43 27 21 45 21 27 16 0 0 44 35 25 4 33 53 68 121 0 44 20 22 44 50 29 43 38 38 45 32 28 Uncertainty in time = +/- 3 secs Prediction of 2012 Jul 21.0 Data for the target star ------------------------ * name: TYC 2421-00398-1 * constellation : Auriga * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 06 25 19.2628 DE: +31 05 40.523 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .027, .029 ) * V mag [mag]: 11.1 * B mag [mag]: 12.0 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (987) Wallia approx. diameter [km]: 52 approx. diameter ["]: .022 distance from Earth [AU]: 3.20300 * orbital information: orbit source: Preston date of fit: 2012 Jul 21 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1111 number of rejected observations: 57 time covered by the observations: 1937 May 01 - 2012 Feb 02 1 sigma uncertainty ellipse (major, minor, PA): 0.017, 0.011, 100° remarks: * orbital elements for (987) Wallia : Mean anomaly = 70.49893012 deg Arg. of pericenter = 16.71433076 deg Long. of node = 322.79542661 deg Inclination = 8.88281625 deg Eccentricity = 0.23197161 Semimajor axis = 3.14980390 AU Perihelion dist = 2.41913882 AU Mag: H = 9.46, G = 0.15 Epoch of elements : MJD 56181.19100000 TDT (2012 Sep 11.191) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 11 987 Wallia 4h 35.0m UT 11.1 6 25 19.263 31 5 40.52TYC 2421-00398-1 12.0 15.2 52 2.3 3.203 2.745 1.73 36.9651 31.094 110.39 4.41 4.5839 -0.01510 0.26752 12.84495 0.63160 -0.00548 0.00047 2000 70.2889442012 910.00000 16.714331322.795427 8.8828160.23197161 3.1498039 2.4191388 9.3 5.00.15 RATE 1.7631070 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.032 0.031 93 2.39 0.031 0 0-2 3 056129.0020120911_0398-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 21, 15:34 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org