IOTA/IOTA-ES occultation update for (8174) 1991 SL2 / UCAC4 322-187225 event on 2024 Mar 14, 01:09 UT Visible from Summary ------- On 2024 Mar 14 UT, the 22.5273474981338 km diameter asteroid (8174) 1991 SL2 will occult a 10.5 mag star in the constellation Sagittarius for observers along a path across . In the case of an occultation, the combined light of the asteroid and the star will drop by 8.14 mag to 18.61 mag (the magnitude of the asteroid) for at most 1.030 seconds. This update is based on, astrometry for the asteroid kindly provided by the IAU Minor Planet Center. This work has made use of data from the European Space Agency (ESA) mission Gaia (http://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, http://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. The event at a glimpse ---------------------- * Rank: 99 * date and approx. time of event: 2024 Mar 14, 01:05 - 2024 Mar 14, 01:13 * geocentric midpoint of event [JD]: 2460383.54830558 * magnitude of target star: 10.47 * magnitude drop [mag]: 8.14 * estimated maximum duration [s]: 1.030 * Moon: 18 % sunlit, 125° distance * Sun: 75° distance * rough path description: The occultation path -------------------- * approximate projected width [km]: 31 * 1 sigma uncertainty interval [path widths]: +/- 0.13 * 1 sigma uncertainty interval [seconds]: +/- 2.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- 0.018, +/- 0.002) * 1 sigma uncertainty ellipse (major, minor, PA): (0.018", 0.001", 97°) * approx speed of asteroid's shadow [km/s]: 23.2347 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC4 322-187225 by 8174 1991 SL2 on 2024 Mar 14 Centre Star Star Sun Path Limits Error Limits Alt E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4 Crn o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " Latitude Latitude Latitude Latitude 26 0 0 40 30 18 1 6 6.2 0 125 -37 40 19 58 40 40 40 40 17 20 40 43 18 .... 27 0 0 39 58 19 1 6 6.3 1 126 -37 39 48 0 40 8 40 39 45 23 40 11 18 -0.35 28 0 0 39 26 17 1 6 6.5 2 126 -37 39 15 59 39 36 36 39 13 22 39 39 15 -0.56 29 0 0 38 54 12 1 6 6.7 3 127 -36 38 43 56 39 4 30 38 41 19 39 7 8 -0.65 30 0 0 38 22 5 1 6 7.1 4 128 -36 38 11 51 38 32 22 38 9 14 38 35 0 -0.70 31 0 0 37 49 59 1 6 7.6 5 128 -36 37 39 45 38 0 14 37 37 9 38 2 51 -0.73 32 0 0 37 17 53 1 6 8.1 6 129 -35 37 7 41 37 28 7 37 5 5 37 30 43 -0.75 33 0 0 36 45 49 1 6 8.8 7 129 -35 36 35 38 36 56 1 36 33 3 36 58 37 -0.76 34 0 0 36 13 48 1 6 9.6 8 130 -34 36 3 39 36 23 58 36 1 4 36 26 34 -0.77 35 0 0 35 41 51 1 6 10.5 9 131 -34 35 31 43 35 52 0 35 29 9 35 54 35 -0.78 36 0 0 35 9 59 1 6 11.5 10 131 -33 34 59 53 35 20 7 34 57 19 35 22 42 -0.79 37 0 0 34 38 14 1 6 12.6 11 132 -33 34 28 10 34 48 20 34 25 36 34 50 54 -0.80 38 0 0 34 6 36 1 6 13.8 12 132 -32 33 56 34 34 16 40 33 54 1 34 19 14 -0.80 39 0 0 33 35 8 1 6 15.1 13 133 -31 33 25 7 33 45 10 33 22 35 33 47 43 -0.80 40 0 0 33 3 48 1 6 16.5 14 134 -31 32 53 50 33 13 49 32 51 18 33 16 22 -0.81 41 0 0 32 32 40 1 6 18.0 15 134 -30 32 22 44 32 42 39 32 20 12 32 45 11 -0.81 42 0 0 32 1 44 1 6 19.7 16 135 -30 31 51 50 32 11 40 31 49 18 32 14 13 -0.82 43 0 0 31 31 1 1 6 21.4 17 135 -29 31 21 8 31 40 55 31 18 38 31 43 27 -0.82 44 0 0 31 0 32 1 6 23.3 18 136 -28 30 50 41 31 10 24 30 48 11 31 12 55 -0.82 45 0 0 30 30 18 1 6 25.2 19 137 -27 30 20 29 30 40 8 30 17 59 30 42 39 -0.82 46 0 0 30 0 19 1 6 27.3 19 137 -27 29 50 33 30 10 8 29 48 4 30 12 38 -0.82 47 0 0 29 30 38 1 6 29.5 20 138 -26 29 20 54 29 40 25 29 18 25 29 42 54 -0.83 48 0 0 29 1 15 1 6 31.8 21 138 -25 28 51 33 29 11 0 28 49 4 29 13 29 -0.83 49 0 0 28 32 11 1 6 34.1 22 139 -24 28 22 30 28 41 53 28 20 3 28 44 22 -0.83 50 0 0 28 3 27 1 6 36.6 23 140 -24 27 53 48 28 13 7 27 51 21 28 15 35 -0.83 51 0 0 27 35 3 1 6 39.2 24 140 -23 27 25 27 27 44 41 27 23 0 27 47 9 -0.83 52 0 0 27 7 1 1 6 41.8 25 141 -22 26 57 26 27 16 37 26 55 0 27 19 4 -0.83 53 0 0 26 39 21 1 6 44.6 26 142 -21 26 29 49 26 48 55 26 27 23 26 51 21 -0.84 54 0 0 26 12 4 1 6 47.5 27 142 -20 26 2 34 26 21 36 26 0 9 26 24 2 -0.84 55 0 0 25 45 12 1 6 50.4 28 143 -20 25 35 43 25 54 41 25 33 19 25 57 7 -0.84 56 0 0 25 18 43 1 6 53.5 29 144 -19 25 9 17 25 28 11 25 6 53 25 30 36 -0.84 57 0 0 24 52 41 1 6 56.6 30 144 -18 24 43 17 25 2 7 24 40 53 25 4 31 -0.84 58 0 0 24 27 4 1 6 59.8 31 145 -17 24 17 42 24 36 28 24 15 19 24 38 52 -0.84 59 0 0 24 1 55 1 7 3.1 31 146 -16 23 52 35 24 11 17 23 50 12 24 13 40 -0.84 60 0 0 23 37 13 1 7 6.5 32 147 -15 23 27 54 23 46 32 23 25 32 23 48 55 -0.84 61 0 0 23 12 58 1 7 10.0 33 147 -14 23 3 42 23 22 16 23 1 20 23 24 39 -0.84 62 0 0 22 49 13 1 7 13.5 34 148 -13 22 39 58 22 58 29 22 37 37 23 0 51 -0.84 63 0 0 22 25 57 1 7 17.1 35 149 -12 22 16 44 22 35 11 22 14 23 22 37 32 -0.85 64 0 0 22 3 10 1 7 20.8 36 150 -12 21 53 59 22 12 22 21 51 39 22 14 43 -0.85 65 0 0 21 40 54 1 7 24.6 36 151 -11 21 31 45 21 50 4 21 29 25 21 52 24 -0.85 66 0 0 21 19 8 1 7 28.4 37 151 -10 21 10 1 21 28 16 21 7 42 21 30 36 -0.85 67 0 0 20 57 54 1 7 32.3 38 152 -9 20 48 48 21 7 0 20 46 29 21 9 20 -0.85 68 0 0 20 37 11 1 7 36.3 39 153 -8 20 28 7 20 46 16 20 25 49 20 48 35 -0.85 69 0 0 20 17 0 1 7 40.3 39 154 -7 20 7 58 20 26 3 20 5 40 20 28 22 -0.85 70 0 0 19 57 21 1 7 44.4 40 155 -6 19 48 21 20 6 23 19 46 4 20 8 41 -0.85 71 0 0 19 38 16 1 7 48.5 41 156 -5 19 29 17 19 47 16 19 27 0 19 49 34 -0.85 72 0 0 19 19 44 1 7 52.7 41 157 -4 19 10 46 19 28 42 19 8 30 19 30 59 -0.85 73 0 0 19 1 45 1 7 57.0 42 158 -3 18 52 49 19 10 42 18 50 33 19 12 59 -0.85 74 0 0 18 44 20 1 8 1.3 43 159 -2 18 35 26 18 53 15 18 33 10 18 55 32 -0.85 75 0 0 18 27 29 1 8 5.6 43 160 -1 18 18 36 18 36 23 18 16 21 18 38 39 -0.85 76 0 0 18 11 12 1 8 10.0 44 161 0 18 2 21 18 20 5 18 0 6 18 22 21 -0.86 77 0 0 17 55 30 1 8 14.4 44 162 1 17 46 40 18 4 21 17 44 25 18 6 37 -0.86 78 0 0 17 40 23 1 8 18.9 45 164 2 17 31 35 17 49 13 17 29 20 17 51 28 -0.86 79 0 0 17 25 51 1 8 23.4 45 165 3 17 17 4 17 34 40 17 14 50 17 36 55 -0.86 80 0 0 17 11 55 1 8 27.9 46 166 4 17 3 9 17 20 42 17 0 55 17 22 57 -0.86 81 0 0 16 58 34 1 8 32.4 46 167 5 16 49 49 17 7 20 16 47 35 17 9 34 -0.86 82 0 0 16 45 48 1 8 37.0 47 169 6 16 37 4 16 54 33 16 34 51 16 56 47 -0.86 83 0 0 16 33 39 1 8 41.6 47 170 7 16 24 56 16 42 23 16 22 43 16 44 36 -0.86 84 0 0 16 22 5 1 8 46.3 47 171 8 16 13 23 16 30 48 16 11 11 16 33 2 -0.86 85 0 0 16 11 8 1 8 50.9 48 172 9 16 2 27 16 19 50 16 0 14 16 22 3 -0.86 86 0 0 16 0 47 1 8 55.6 48 174 10 15 52 7 16 9 28 15 49 54 16 11 41 -0.86 87 0 0 15 51 2 1 9 0.3 48 175 11 15 42 23 15 59 42 15 40 11 16 1 55 -0.86 88 0 0 15 41 54 1 9 5.0 49 176 12 15 33 16 15 50 33 15 31 4 15 52 46 -0.86 89 0 0 15 33 22 1 9 9.7 49 178 13 15 24 45 15 42 1 15 22 33 15 44 13 -0.86 90 0 0 15 25 28 1 9 14.4 49 179 14 15 16 51 15 34 5 15 14 39 15 36 18 -0.86 91 0 0 15 18 10 1 9 19.2 49 181 15 15 9 33 15 26 47 15 7 22 15 28 59 -0.86 92 0 0 15 11 29 1 9 23.9 49 182 16 15 2 53 15 20 5 15 0 42 15 22 17 -0.86 93 0 0 15 5 25 1 9 28.7 49 183 17 14 56 50 15 14 1 14 54 38 15 16 12 -0.86 94 0 0 14 59 57 1 9 33.4 49 185 18 14 51 23 15 8 33 14 49 12 15 10 45 -0.86 95 0 0 14 55 7 1 9 38.1 49 186 19 14 46 33 15 3 42 14 44 22 15 5 54 -0.86 96 0 0 14 50 54 1 9 42.9 49 188 20 14 42 21 14 59 29 14 40 10 15 1 40 -0.86 97 0 0 14 47 18 1 9 47.6 49 189 21 14 38 45 14 55 53 14 36 34 14 58 4 -0.86 98 0 0 14 44 20 1 9 52.3 49 190 22 14 35 47 14 52 54 14 33 36 14 55 5 -0.86 99 0 0 14 41 58 1 9 57.0 49 192 23 14 33 25 14 50 32 14 31 15 14 52 43 -0.86 100 0 0 14 40 14 1 10 1.7 49 193 24 14 31 41 14 48 48 14 29 31 14 50 59 -0.87 101 0 0 14 39 7 1 10 6.4 48 195 25 14 30 34 14 47 40 14 28 24 14 49 52 -0.87 102 0 0 14 38 37 1 10 11.0 48 196 26 14 30 4 14 47 11 14 27 54 14 49 22 -0.87 103 0 0 14 38 44 1 10 15.7 48 197 27 14 30 12 14 47 18 14 28 1 14 49 29 -0.87 104 0 0 14 39 29 1 10 20.3 48 198 28 14 30 56 14 48 2 14 28 46 14 50 14 -0.87 105 0 0 14 40 50 1 10 24.9 47 200 29 14 32 18 14 49 24 14 30 7 14 51 35 -0.87 106 0 0 14 42 49 1 10 29.4 47 201 29 14 34 16 14 51 23 14 32 6 14 53 34 -0.87 107 0 0 14 45 25 1 10 34.0 46 202 30 14 36 52 14 53 59 14 34 42 14 56 11 -0.87 108 0 0 14 48 38 1 10 38.5 46 203 31 14 40 5 14 57 13 14 37 54 14 59 24 -0.87 109 0 0 14 52 28 1 10 43.0 46 205 32 14 43 55 15 1 3 14 41 44 15 3 14 -0.87 110 0 0 14 56 55 1 10 47.4 45 206 33 14 48 21 15 5 31 14 46 11 15 7 42 -0.87 111 0 0 15 2 0 1 10 51.8 45 207 34 14 53 25 15 10 35 14 51 14 15 12 47 -0.87 112 0 0 15 7 40 1 10 56.2 44 208 35 14 59 5 15 16 16 14 56 54 15 18 28 -0.87 113 0 0 15 13 58 1 11 0.5 43 209 36 15 5 23 15 22 35 15 3 11 15 24 47 -0.87 114 0 0 15 20 53 1 11 4.8 43 210 37 15 12 16 15 29 30 15 10 5 15 31 42 -0.87 115 0 0 15 28 24 1 11 9.0 42 211 38 15 19 47 15 37 1 15 17 35 15 39 14 -0.87 116 0 0 15 36 31 1 11 13.2 42 212 39 15 27 54 15 45 10 15 25 42 15 47 22 -0.87 117 0 0 15 45 15 1 11 17.3 41 213 40 15 36 37 15 53 55 15 34 25 15 56 7 -0.87 118 0 0 15 54 36 1 11 21.4 40 214 41 15 45 57 16 3 16 15 43 45 16 5 28 -0.87 119 0 0 16 4 32 1 11 25.4 40 215 41 15 55 52 16 13 13 15 53 40 16 15 26 -0.87 120 0 0 16 15 5 1 11 29.4 39 215 42 16 6 24 16 23 47 16 4 12 16 26 0 -0.87 121 0 0 16 26 13 1 11 33.3 38 216 43 16 17 32 16 34 56 16 15 19 16 37 10 -0.87 122 0 0 16 37 58 1 11 37.2 37 217 44 16 29 15 16 46 42 16 27 2 16 48 56 -0.87 123 0 0 16 50 18 1 11 41.0 37 218 45 16 41 35 16 59 3 16 39 22 17 1 17 -0.87 124 0 0 17 3 14 1 11 44.7 36 219 46 16 54 29 17 12 0 16 52 16 17 14 14 -0.87 125 0 0 17 16 45 1 11 48.4 35 219 47 17 7 59 17 25 32 17 5 45 17 27 46 -0.87 126 0 0 17 30 51 1 11 52.0 34 220 47 17 22 4 17 39 39 17 19 49 17 41 54 -0.87 127 0 0 17 45 32 1 11 55.5 34 221 48 17 36 43 17 54 21 17 34 29 17 56 36 -0.87 128 0 0 18 0 47 1 11 58.9 33 221 49 17 51 57 18 9 38 17 49 42 18 11 53 -0.87 129 0 0 18 16 37 1 12 2.3 32 222 50 18 7 46 18 25 29 18 5 31 18 27 45 -0.87 130 0 0 18 33 1 1 12 5.6 31 223 50 18 24 8 18 41 54 18 21 53 18 44 11 -0.87 131 0 0 18 49 58 1 12 8.8 30 223 51 18 41 5 18 58 54 18 38 49 19 1 10 -0.87 132 0 0 19 7 30 1 12 12.0 29 224 52 18 58 34 19 16 26 18 56 18 19 18 43 -0.87 133 0 0 19 25 34 1 12 15.0 28 225 52 19 16 38 19 34 32 19 14 21 19 36 50 -0.87 134 0 0 19 44 12 1 12 18.0 28 225 53 19 35 14 19 53 12 19 32 57 19 55 29 -0.87 135 0 0 20 3 22 1 12 20.9 27 226 54 19 54 22 20 12 23 19 52 5 20 14 41 -0.87 136 0 0 20 23 4 1 12 23.7 26 226 54 20 14 3 20 32 7 20 11 45 20 34 26 -0.87 137 0 0 20 43 18 1 12 26.4 25 227 55 20 34 15 20 52 23 20 31 57 20 54 42 -0.87 138 0 0 21 4 4 1 12 29.0 24 227 55 20 54 59 21 13 10 20 52 40 21 15 29 -0.87 139 0 0 21 25 20 1 12 31.6 23 228 56 21 16 14 21 34 28 21 13 55 21 36 48 -0.87 140 0 0 21 47 7 1 12 34.0 22 228 56 21 37 59 21 56 17 21 35 39 21 58 38 -0.87 141 0 0 22 9 25 1 12 36.3 21 229 57 22 0 14 22 18 36 21 57 54 22 20 57 -0.87 142 0 0 22 32 11 1 12 38.6 20 229 57 22 22 59 22 41 25 22 20 39 22 43 46 -0.87 143 0 0 22 55 28 1 12 40.7 19 230 57 22 46 14 23 4 43 22 43 53 23 7 5 -0.87 144 0 0 23 19 12 1 12 42.7 18 230 58 23 9 56 23 28 29 23 7 35 23 30 52 -0.87 145 0 0 23 43 25 1 12 44.7 17 231 58 23 34 7 23 52 44 23 31 45 23 55 6 -0.87 146 0 0 24 8 4 1 12 46.5 16 231 58 23 58 45 24 17 25 23 56 22 24 19 49 -0.87 147 0 0 24 33 11 1 12 48.2 15 232 58 24 23 49 24 42 34 24 21 26 24 44 58 -0.87 148 0 0 24 58 44 1 12 49.8 14 232 59 24 49 20 25 8 9 24 46 57 25 10 33 -0.87 149 0 0 25 24 42 1 12 51.4 13 233 59 25 15 17 25 34 9 25 12 53 25 36 34 -0.87 150 0 0 25 51 5 1 12 52.8 12 233 59 25 41 38 26 0 34 25 39 13 26 2 59 -0.87 151 0 0 26 17 52 1 12 54.1 11 234 59 26 8 23 26 27 23 26 5 58 26 29 49 -0.87 152 0 0 26 45 3 1 12 55.2 10 234 59 26 35 31 26 54 36 26 33 6 26 57 2 -0.88 153 0 0 27 12 36 1 12 56.3 9 235 59 27 3 2 27 22 11 27 0 37 27 24 38 -0.88 154 0 0 27 40 31 1 12 57.3 8 235 58 27 30 55 27 50 8 27 28 29 27 52 35 -0.88 155 0 0 28 8 47 1 12 58.1 7 236 58 27 59 9 28 18 26 27 56 42 28 20 54 -0.88 156 0 0 28 37 23 1 12 58.9 6 236 58 28 27 43 28 47 4 28 25 16 28 49 33 -0.89 157 0 0 29 6 18 1 12 59.5 5 237 58 28 56 37 29 16 2 28 54 9 29 18 30 -0.89 158 0 0 29 35 32 1 13 0.0 4 237 58 29 25 48 29 45 17 29 23 20 29 47 47 -0.90 159 0 0 30 5 3 1 13 0.5 3 238 57 29 55 18 30 14 51 29 52 49 30 17 21 -0.92 160 0 0 30 34 51 1 13 0.8 2 238 57 30 25 3 30 44 40 30 22 34 30 47 11 -0.94 161 0 0 31 4 55 1 13 0.9 1 239 56 30 55 5 31 14 46 30 52 35 31 17 17 -1.01 162 0 0 31 35 13 1 13 1.0 0 239 56 31 25 21 31 45 6 31 22 51 31 47 37 -1.46 Uncertainty in time = +/- 2 secs Prediction of 2023 Jul 14.2 Data for the target star ------------------------ * name: UCAC4 322-187225 * constellation : Sagittarius * BCRS position with proper motion to date of event [h,m,s ; °,',"] RA: 18 38 32.5336 DE: -25 46 31.946 * GCRS Astrometric position with proper motion and parallax to date of event [h,m,s ; °,',"] RA: 18 38 32.5337 DE: -25 46 31.946 * position source: Gaia DR3 * standard error: RA,DE [mas]: (0.300,0.200) * V mag [mag]: 10.5 * B mag [mag]: 12.3 * Diameter [mas]: 0.50 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (8174) 1991 SL2 asteroid class: approx. diameter [km]: 23 approx. diameter ["]: 0.009 distance from Earth [AU]: 3.61700 asteroid position offset in RA [mas]: 0 asteroid position offset in DE [mas]: 0 * orbital information: orbit source: JPL#53 date of fit: 2023 Apr 25 source of used astrometry: MPC, JPL number of used observations: 0 number of rejected observations: 0 time covered by the observations: 1800 Jan 01 - 1800 Jan 01 1 sigma uncertainty ellipse (major, minor, PA): 0.018", 0.001", 96.7° remarks: * orbital elements for (8174)1991 SL2 : Mean anomaly = 231.5614506408 deg Arg. of pericenter = 335.2523975480 deg Long. of node = 67.6082608913 deg Inclination = 10.3301797885 deg Eccentricity = 0.1430313298 Semimajor axis = 3.1760981123 AU Perihelion dist = 2.7218165756 AU Mag: H = 12.25, G = 0.15 Epoch of elements : MJD 60383.04830563 TDT (2024 Mar 14.0483) ------ occelmnt file for Occult BEGIN ----------------------------------- JPL#532023Apr25,1.03,2024,3,14,1.159334,0.060326,0.650528,13.058732,-1.205859,-0.005761,-0.000471,0.000000,0.000000 90.4654,-25.7550,164.91,-2.40,False UCAC4 322-187225,18.64237043,-25.7755406,12.27,10.47,9.50,0.5,0,,18.66711206,-25.7550475,8.14,8.67,0,0,0 8174,1991 SL2,18.61,23.839,3.6170,0,0,2.351,-2.93,,2.0,0 0,231.3789,2024,3,13,335.2524,67.6083,10.3302,0.14303,3.17610,2.72182,12.24,5.0,0.15 1.127,0.0180,0.0011,97,0.0012,Known errors,0.89,0,-1,-1 20240314_187225,60139.23 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2023 Jul 14, 05:34 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 stevepr@acm.org