IOTA/IOTA-ES occultation update for (924) Toni / TYC 4974-00584-1 event on 2012 Dec 25, 10:43 UT Visible from N Canada Summary ------- On 2012 Dec 25 UT, the 78 km diameter asteroid (924) Toni will occult a 9.0 mag star in the constellation Virgo for observers along a path across N Canada. In the case of an occultation, the combined light of the asteroid and the star will drop by 6.7 mag to 15.7 mag (the magnitude of the asteroid) for at most 2.9 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: UCAC. The event at a glimpse ---------------------- * Rank: 57 * date and approx. time of event: 2012 Dec 25, 10:41 - 2012 Dec 25, 10:43 UT * geocentric midpoint of event [JD]: 2456286.94685 * magnitude of target star: 9.0 * magnitude drop [mag]: 6.7 * estimated maximum duration [s]: 2.9 * Moon: 92 % sunlit, 147° distance * Sun: 65° distance * rough path description: N Canada The occultation path -------------------- * approximate projected width [km]: 149 * 1 sigma uncertainty interval [path widths]: +/- 1.09 * 1 sigma uncertainty interval [seconds]: +/- 2.9 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .030 +/- .032) * 1 sigma uncertainty ellipse (major, minor, PA): ( .032", .030", 2° ) * approx speed of asteroid's shadow [km/s]: 27.2738 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 4974-00584-1 by 924 Toni on 2012 Dec 25 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 ' " Longitude Longitude Longitude Longitude -111 37 39 69 0 0 10 41 28 3 115 -36 -117 25 57 -106 17 30 ... .. .. - 95 41 43 -104 27 38 68 0 0 10 41 29 6 121 -34 -109 25 53 - 99 45 42 ... .. .. - 90 9 35 Latitude Latitude Latitude Latitude -104 0 0 67 55 50 10 41 30 6 122 -34 67 12 49 68 39 49 65 42 7 70 19 29 -103 0 0 67 46 39 10 41 30 6 123 -34 67 3 33 68 30 43 65 32 42 70 10 35 -102 0 0 67 37 17 10 41 30 7 124 -33 66 54 7 68 21 26 65 23 6 70 1 30 -101 0 0 67 27 44 10 41 31 7 125 -33 66 44 30 68 11 58 65 13 20 69 52 14 -100 0 0 67 18 1 10 41 31 8 125 -33 66 34 42 68 2 20 65 3 24 69 42 47 - 99 0 0 67 8 7 10 41 32 8 126 -32 66 24 43 67 52 30 64 53 17 69 33 9 - 98 0 0 66 58 2 10 41 32 8 127 -32 66 14 34 67 42 30 64 42 59 69 23 20 - 97 0 0 66 47 46 10 41 33 9 128 -32 66 4 14 67 32 18 64 32 31 69 13 20 - 96 0 0 66 37 20 10 41 33 9 129 -31 65 53 44 67 21 56 64 21 52 69 3 8 - 95 0 0 66 26 43 10 41 34 10 130 -31 65 43 3 67 11 24 64 11 3 68 52 46 - 94 0 0 66 15 55 10 41 34 10 131 -31 65 32 11 67 0 40 64 0 4 68 42 13 - 93 0 0 66 4 57 10 41 35 11 132 -30 65 21 9 66 49 46 63 48 54 68 31 29 - 92 0 0 65 53 48 10 41 35 11 133 -30 65 9 57 66 38 41 63 37 34 68 20 34 - 91 0 0 65 42 29 10 41 36 11 134 -30 64 58 34 66 27 26 63 26 5 68 9 28 - 90 0 0 65 30 59 10 41 37 12 135 -29 64 47 1 66 16 0 63 14 25 67 58 11 - 89 0 0 65 19 19 10 41 38 12 136 -29 64 35 18 66 4 24 63 2 35 67 46 44 - 88 0 0 65 7 29 10 41 38 13 137 -28 64 23 25 65 52 37 62 50 35 67 35 6 - 87 0 0 64 55 29 10 41 39 13 138 -28 64 11 21 65 40 41 62 38 26 67 23 17 - 86 0 0 64 43 19 10 41 40 14 139 -28 63 59 8 65 28 34 62 26 8 67 11 17 - 85 0 0 64 30 59 10 41 41 14 140 -27 63 46 46 65 16 17 62 13 40 66 59 8 - 84 0 0 64 18 30 10 41 42 14 141 -27 63 34 14 65 3 50 62 1 2 66 46 48 - 83 0 0 64 5 51 10 41 43 15 141 -26 63 21 32 64 51 13 61 48 16 66 34 18 - 82 0 0 63 53 2 10 41 44 15 142 -26 63 8 41 64 38 27 61 35 21 66 21 38 - 81 0 0 63 40 5 10 41 45 16 143 -25 62 55 42 64 25 32 61 22 17 66 8 48 - 80 0 0 63 26 58 10 41 46 16 144 -25 62 42 33 64 12 27 61 9 4 65 55 48 - 79 0 0 63 13 42 10 41 47 17 145 -25 62 29 15 63 59 13 60 55 43 65 42 39 - 78 0 0 63 0 18 10 41 48 17 146 -24 62 15 50 63 45 51 60 42 14 65 29 20 - 77 0 0 62 46 45 10 41 49 18 147 -24 62 2 15 63 32 19 60 28 37 65 15 52 - 76 0 0 62 33 4 10 41 51 18 148 -23 61 48 33 63 18 40 60 14 53 65 2 16 - 75 0 0 62 19 15 10 41 52 18 149 -23 61 34 43 63 4 52 60 1 1 64 48 31 - 74 0 0 62 5 18 10 41 53 19 150 -22 61 20 46 62 50 56 59 47 2 64 34 37 - 73 0 0 61 51 14 10 41 55 19 151 -22 61 6 41 62 36 52 59 32 56 64 20 35 - 72 0 0 61 37 3 10 41 56 20 152 -21 60 52 29 62 22 41 59 18 43 64 6 25 - 71 0 0 61 22 44 10 41 57 20 153 -21 60 38 10 62 8 23 59 4 24 63 52 7 - 70 0 0 61 8 19 10 41 59 21 154 -20 60 23 45 61 53 58 58 49 58 63 37 42 - 69 0 0 60 53 48 10 42 0 21 155 -20 60 9 14 61 39 27 58 35 27 63 23 10 - 68 0 0 60 39 10 10 42 2 21 156 -19 59 54 37 61 24 49 58 20 51 63 8 32 - 67 0 0 60 24 27 10 42 4 22 157 -18 59 39 54 61 10 5 58 6 9 62 53 46 - 66 0 0 60 9 38 10 42 5 22 158 -18 59 25 6 60 55 16 57 51 22 62 38 55 - 65 0 0 59 54 45 10 42 7 23 159 -17 59 10 13 60 40 21 57 36 31 62 23 58 - 64 0 0 59 39 46 10 42 9 23 160 -17 58 55 16 60 25 21 57 21 36 62 8 55 - 63 0 0 59 24 43 10 42 10 23 161 -16 58 40 14 60 10 17 57 6 37 61 53 47 - 62 0 0 59 9 37 10 42 12 24 162 -16 58 25 9 59 55 9 56 51 34 61 38 35 - 61 0 0 58 54 26 10 42 14 24 164 -15 58 10 0 59 39 56 56 36 29 61 23 19 - 60 0 0 58 39 13 10 42 16 25 165 -14 57 54 48 59 24 41 56 21 21 61 7 58 - 59 0 0 58 23 56 10 42 18 25 166 -14 57 39 34 59 9 22 56 6 10 60 52 34 - 58 0 0 58 8 37 10 42 20 25 167 -13 57 24 17 58 54 1 55 50 58 60 37 7 - 57 0 0 57 53 16 10 42 22 26 168 -13 57 8 59 58 38 38 55 35 43 60 21 37 - 56 0 0 57 37 54 10 42 24 26 169 -12 56 53 39 58 23 12 55 20 28 60 6 5 - 55 0 0 57 22 30 10 42 26 27 170 -12 56 38 17 58 7 46 55 5 12 59 50 31 - 54 0 0 57 7 5 10 42 28 27 171 -11 56 22 56 57 52 18 54 49 56 59 34 56 - 53 0 0 56 51 40 10 42 30 27 172 -10 56 7 34 57 36 50 54 34 40 59 19 20 - 52 0 0 56 36 16 10 42 33 28 173 -10 55 52 12 57 21 22 54 19 24 59 3 44 - 51 0 0 56 20 51 10 42 35 28 174 -9 55 36 51 57 5 54 54 4 10 58 48 8 - 50 0 0 56 5 28 10 42 37 28 176 -8 55 21 31 56 50 27 53 48 56 58 32 32 - 49 0 0 55 50 6 10 42 39 28 177 -8 55 6 13 56 35 1 53 33 45 58 16 57 - 48 0 0 55 34 46 10 42 42 29 178 -7 54 50 56 56 19 37 53 18 35 58 1 23 - 47 0 0 55 19 28 10 42 44 29 179 -7 54 35 42 56 4 16 53 3 29 57 45 52 - 46 0 0 55 4 13 10 42 46 29 180 -6 54 20 31 55 48 57 52 48 25 57 30 22 - 45 0 0 54 49 2 10 42 49 29 181 -5 54 5 23 55 33 41 52 33 25 57 14 56 - 44 0 0 54 33 54 10 42 51 30 182 -5 53 50 19 55 18 28 52 18 29 56 59 33 - 43 0 0 54 18 50 10 42 54 30 184 -4 53 35 20 55 3 20 52 3 38 56 44 14 - 42 0 0 54 3 51 10 42 56 30 185 -3 53 20 25 54 48 16 51 48 51 56 28 59 - 41 0 0 53 48 56 10 42 59 30 186 -3 53 5 35 54 33 17 51 34 9 56 13 48 - 40 0 0 53 34 7 10 43 1 31 187 -2 52 50 50 54 18 24 51 19 33 55 58 43 - 39 0 0 53 19 25 10 43 4 31 188 -2 52 36 12 54 3 36 51 5 4 55 43 44 - 38 0 0 53 4 48 10 43 7 31 190 -1 52 21 40 53 48 55 50 50 41 55 28 51 - 37 0 0 52 50 19 10 43 9 31 191 0 52 7 15 53 34 21 50 36 25 55 14 5 Uncertainty in time = +/- 3 secs Prediction of 2012 Dec 17.0 Data for the target star ------------------------ * name: TYC 4974-00584-1 * constellation : Virgo * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 13 54 58.2739 DE: -05 43 55.030 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .027, .030 ) * V mag [mag]: 9.0 * B mag [mag]: 9.6 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (924) Toni approx. diameter [km]: 78 approx. diameter ["]: .029 distance from Earth [AU]: 3.69100 * orbital information: orbit source: Preston date of fit: 2012 Jul 10 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1265 number of rejected observations: 100 time covered by the observations: 1906 Jan 22 - 2012 May 16 1 sigma uncertainty ellipse (major, minor, PA): 0.013, 0.010, 106° remarks: * orbital elements for (924) Toni : Mean anomaly = 185.76400755 deg Arg. of pericenter = 219.03569587 deg Long. of node = 150.51572400 deg Inclination = 8.99465005 deg Eccentricity = 0.15774080 Semimajor axis = 2.93658267 AU Perihelion dist = 2.47336376 AU Mag: H = 9.35, G = 0.15 Epoch of elements : MJD 56286.44700000 TDT (2012 Dec 25.447) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Dec 25 924 Toni 10h 43.5m UT 9.0 13 54 58.274- 5 43 55.03TYC 4974-00584-1 9.6 15.7 78 2.9 3.691 2.403 -7.64 -46.4742 -5.729 19.21 -23.37 10.7244 0.17446 0.83307 15.05586 -3.20936 -0.00506 0.00216 2000 184.50131320121219.00000219.035696150.515724 8.9946500.15774080 2.9365827 2.4733638 9.4 5.00.15 RATE 1.9585780 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.032 0.030 2 2.09 0.032 0 0-1 0 056278.0020121225_0584-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 10, 06:39 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org