IOTA/IOTA-ES occultation update for (54) Alexandra / UCAC4 306-279491 event on 2023 May 30, 08:00 UT Visible from South America Summary ------- On 2023 May 30 UT, the 152.1 km diameter asteroid (54) Alexandra will occult a 12.2 mag star in the constellation Microscopium for observers along a path across South America. In the case of an occultation, the combined light of the asteroid and the star will drop by 0.46 mag to 11.47 mag (the magnitude of the asteroid) for at most 41.820 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: 100 * date and approx. time of event: 2023 May 30, 07:33 - 2023 May 30, 08:26 * geocentric midpoint of event [JD]: 2460094.83323442 * magnitude of target star: 12.17 * magnitude drop [mag]: 0.46 * estimated maximum duration [s]: 41.820 * Moon: 75 % sunlit, 115° distance * Sun: 125° distance * rough path description: South America Additional comments ------------------- low mag drop The occultation path -------------------- * approximate projected width [km]: 176 * 1 sigma uncertainty interval [path widths]: +/- 0.01 * 1 sigma uncertainty interval [seconds]: +/- 7.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- 0.023, +/- 0.012) * 1 sigma uncertainty ellipse (major, minor, PA): (0.026", 0.001", 62°) * approx speed of asteroid's shadow [km/s]: 3.6373 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC4 306-279491 by 54 Alexandra on 2023 May 30 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 -143 0 0 - 0 54 43 7 34 36.5 0 119 -55 - 1 47 13 - 0 1 45 - 1 48 29 .. .. .. .... -142 0 0 - 1 27 13 7 34 37.1 2 119 -56 - 2 19 27 - 0 34 31 - 2 20 42 - 0 33 14 -0.22 -141 0 0 - 1 58 53 7 34 38.6 3 119 -57 - 2 50 51 - 1 6 27 - 2 52 7 - 1 5 11 -0.34 -140 0 0 - 2 29 43 7 34 40.9 4 119 -58 - 3 21 26 - 1 37 33 - 3 22 41 - 1 36 17 -0.40 -139 0 0 - 2 59 42 7 34 43.9 5 119 -60 - 3 51 10 - 2 7 47 - 3 52 25 - 2 6 32 -0.43 -138 0 0 - 3 28 50 7 34 47.7 6 119 -61 - 4 20 4 - 2 37 11 - 4 21 18 - 2 35 55 -0.44 -137 0 0 - 3 57 7 7 34 52.2 7 119 -62 - 4 48 6 - 3 5 42 - 4 49 20 - 3 4 27 -0.46 -136 0 0 - 4 24 33 7 34 57.5 8 118 -63 - 5 15 18 - 3 33 22 - 5 16 31 - 3 32 7 -0.47 -135 0 0 - 4 51 7 7 35 3.6 9 118 -64 - 5 41 38 - 4 0 10 - 5 42 51 - 3 58 55 -0.48 -134 0 0 - 5 16 48 7 35 10.3 10 118 -65 - 6 7 6 - 4 26 5 - 6 8 19 - 4 24 50 -0.48 -133 0 0 - 5 41 37 7 35 17.8 12 118 -66 - 6 31 43 - 4 51 7 - 6 32 55 - 4 49 53 -0.49 -132 0 0 - 6 5 34 7 35 26.0 13 118 -67 - 6 55 27 - 5 15 16 - 6 56 39 - 5 14 2 -0.50 -131 0 0 - 6 28 38 7 35 34.9 14 118 -68 - 7 18 19 - 5 38 32 - 7 19 31 - 5 37 19 -0.50 -130 0 0 - 6 50 49 7 35 44.4 15 118 -69 - 7 40 18 - 6 0 55 - 7 41 30 - 5 59 42 -0.50 -129 0 0 - 7 12 7 7 35 54.7 16 118 -70 - 8 1 25 - 6 22 24 - 8 2 36 - 6 21 11 -0.51 -128 0 0 - 7 32 31 7 36 5.6 17 118 -71 - 8 21 39 - 6 42 59 - 8 22 50 - 6 41 47 -0.51 -127 0 0 - 7 52 3 7 36 17.2 18 118 -72 - 8 41 0 - 7 2 41 - 8 42 11 - 7 1 29 -0.52 -126 0 0 - 8 10 41 7 36 29.5 19 118 -73 - 8 59 29 - 7 21 29 - 9 0 39 - 7 20 17 -0.52 -125 0 0 - 8 28 25 7 36 42.3 20 118 -73 - 9 17 4 - 7 39 23 - 9 18 14 - 7 38 11 -0.52 -124 0 0 - 8 45 16 7 36 55.9 21 118 -74 - 9 33 46 - 7 56 22 - 9 34 56 - 7 55 11 -0.53 -123 0 0 - 9 1 13 7 37 10.0 22 118 -75 - 9 49 35 - 8 12 28 - 9 50 45 - 8 11 16 -0.53 -122 0 0 - 9 16 16 7 37 24.8 23 117 -76 -10 4 30 - 8 27 38 -10 5 40 - 8 26 27 -0.53 -121 0 0 - 9 30 25 7 37 40.2 24 117 -76 -10 18 32 - 8 41 55 -10 19 42 - 8 40 44 -0.54 -120 0 0 - 9 43 40 7 37 56.2 25 117 -77 -10 31 40 - 8 55 16 -10 32 50 - 8 54 6 -0.54 -119 0 0 - 9 56 0 7 38 12.8 26 117 -78 -10 43 55 - 9 7 43 -10 45 4 - 9 6 33 -0.54 -118 0 0 -10 7 27 7 38 29.9 27 117 -78 -10 55 15 - 9 19 15 -10 56 25 - 9 18 5 -0.54 -117 0 0 -10 17 58 7 38 47.7 28 117 -78 -11 5 42 - 9 29 52 -11 6 51 - 9 28 42 -0.55 -116 0 0 -10 27 36 7 39 6.1 30 117 -79 -11 15 15 - 9 39 33 -11 16 24 - 9 38 23 -0.55 -115 0 0 -10 36 18 7 39 25.0 31 117 -79 -11 23 53 - 9 48 20 -11 25 2 - 9 47 10 -0.55 -114 0 0 -10 44 5 7 39 44.5 32 117 -79 -11 31 37 - 9 56 10 -11 32 46 - 9 55 0 -0.56 -113 0 0 -10 50 57 7 40 4.5 33 117 -79 -11 38 27 -10 3 5 -11 39 36 -10 1 55 -0.56 -112 0 0 -10 56 54 7 40 25.2 34 117 -79 -11 44 21 -10 9 4 -11 45 30 -10 7 54 -0.56 -111 0 0 -11 1 55 7 40 46.4 34 118 -78 -11 49 21 -10 14 6 -11 50 30 -10 12 57 -0.56 -110 0 0 -11 6 0 7 41 8.1 35 118 -78 -11 53 25 -10 18 12 -11 54 34 -10 17 3 -0.57 -109 0 0 -11 9 10 7 41 30.4 36 118 -77 -11 56 34 -10 21 22 -11 57 43 -10 20 12 -0.57 -108 0 0 -11 11 22 7 41 53.2 37 118 -77 -11 58 48 -10 23 34 -11 59 56 -10 22 24 -0.57 -107 0 0 -11 12 38 7 42 16.6 38 118 -76 -12 0 5 -10 24 49 -12 1 13 -10 23 39 -0.57 -106 0 0 -11 12 57 7 42 40.5 39 118 -76 -12 0 26 -10 25 6 -12 1 34 -10 23 56 -0.57 -105 0 0 -11 12 19 7 43 5.0 40 118 -75 -11 59 50 -10 24 26 -12 0 58 -10 23 16 -0.58 -104 0 0 -11 10 43 7 43 30.0 41 119 -74 -11 58 17 -10 22 46 -11 59 26 -10 21 36 -0.58 -103 0 0 -11 8 9 7 43 55.6 42 119 -73 -11 55 46 -10 20 8 -11 56 55 -10 18 58 -0.58 -102 0 0 -11 4 37 7 44 21.6 43 119 -72 -11 52 18 -10 16 31 -11 53 27 -10 15 21 -0.58 -101 0 0 -11 0 5 7 44 48.2 44 120 -71 -11 47 52 -10 11 54 -11 49 1 -10 10 44 -0.58 -100 0 0 -10 54 34 7 45 15.4 45 120 -70 -11 42 26 -10 6 17 -11 43 36 -10 5 7 -0.58 - 99 0 0 -10 48 3 7 45 43.1 46 121 -69 -11 36 2 - 9 59 39 -11 37 11 - 9 58 28 -0.58 - 98 0 0 -10 40 31 7 46 11.3 47 121 -69 -11 28 38 - 9 52 0 -11 29 47 - 9 50 49 -0.59 - 97 0 0 -10 31 59 7 46 40.0 48 122 -68 -11 20 13 - 9 43 19 -11 21 23 - 9 42 8 -0.59 - 96 0 0 -10 22 24 7 47 9.3 48 122 -66 -11 10 48 - 9 33 36 -11 11 58 - 9 32 24 -0.59 - 95 0 0 -10 11 48 7 47 39.1 49 123 -65 -11 0 21 - 9 22 49 -11 1 31 - 9 21 38 -0.59 - 94 0 0 -10 0 8 7 48 9.4 50 124 -64 -10 48 52 - 9 10 59 -10 50 2 - 9 9 47 -0.59 - 93 0 0 - 9 47 25 7 48 40.3 51 124 -63 -10 36 20 - 8 58 5 -10 37 31 - 8 56 53 -0.59 - 92 0 0 - 9 33 38 7 49 11.7 52 125 -62 -10 22 45 - 8 44 5 -10 23 56 - 8 42 53 -0.59 - 91 0 0 - 9 18 46 7 49 43.6 52 126 -61 -10 8 5 - 8 29 0 -10 9 17 - 8 27 47 -0.59 - 90 0 0 - 9 2 48 7 50 16.0 53 127 -60 - 9 52 21 - 8 12 48 - 9 53 33 - 8 11 35 -0.59 - 89 0 0 - 8 45 44 7 50 48.9 54 128 -59 - 9 35 31 - 7 55 28 - 9 36 43 - 7 54 15 -0.59 - 88 0 0 - 8 27 32 7 51 22.4 55 129 -58 - 9 17 35 - 7 37 1 - 9 18 47 - 7 35 47 -0.59 - 87 0 0 - 8 8 12 7 51 56.4 55 130 -57 - 8 58 31 - 7 17 25 - 8 59 44 - 7 16 10 -0.59 - 86 0 0 - 7 47 44 7 52 30.9 56 132 -55 - 8 38 20 - 6 56 38 - 8 39 33 - 6 55 24 -0.59 - 85 0 0 - 7 26 5 7 53 5.8 56 133 -54 - 8 17 0 - 6 34 42 - 8 18 13 - 6 33 27 -0.59 - 84 0 0 - 7 3 17 7 53 41.3 57 135 -53 - 7 54 30 - 6 11 34 - 7 55 44 - 6 10 18 -0.59 - 83 0 0 - 6 39 17 7 54 17.3 58 136 -52 - 7 30 50 - 5 47 13 - 7 32 4 - 5 45 57 -0.59 - 82 0 0 - 6 14 4 7 54 53.8 58 138 -51 - 7 5 58 - 5 21 40 - 7 7 13 - 5 20 23 -0.59 - 81 0 0 - 5 47 39 7 55 30.7 58 140 -50 - 6 39 54 - 4 54 53 - 6 41 10 - 4 53 36 -0.59 - 80 0 0 - 5 20 1 7 56 8.1 59 141 -48 - 6 12 38 - 4 26 51 - 6 13 54 - 4 25 33 -0.59 - 79 0 0 - 4 51 7 7 56 46.0 59 143 -47 - 5 44 8 - 3 57 34 - 5 45 24 - 3 56 15 -0.59 - 78 0 0 - 4 20 58 7 57 24.3 59 145 -46 - 5 14 23 - 3 27 0 - 5 15 40 - 3 25 41 -0.59 - 77 0 0 - 3 49 33 7 58 3.0 60 147 -45 - 4 43 23 - 2 55 9 - 4 44 41 - 2 53 49 -0.58 - 76 0 0 - 3 16 52 7 58 42.2 60 149 -43 - 4 11 7 - 2 22 1 - 4 12 26 - 2 20 41 -0.58 - 75 0 0 - 2 42 53 7 59 21.7 60 152 -42 - 3 37 35 - 1 47 34 - 3 38 54 - 1 46 13 -0.58 - 74 0 0 - 2 7 36 8 0 1.6 60 154 -41 - 3 2 46 - 1 11 49 - 3 4 6 - 1 10 27 -0.58 - 73 0 0 - 1 31 1 8 0 41.8 60 156 -39 - 2 26 39 - 0 34 44 - 2 28 0 - 0 33 22 -0.58 - 72 0 0 - 0 53 7 8 1 22.4 60 158 -38 - 1 49 15 0 3 40 - 1 50 36 0 5 3 -0.57 - 71 0 0 - 0 13 54 8 2 3.3 60 160 -37 - 1 10 32 0 43 24 - 1 11 54 0 44 47 -0.57 - 70 0 0 0 26 39 8 2 44.4 59 163 -35 - 0 30 30 1 24 28 - 0 31 53 1 25 52 -0.57 - 69 0 0 1 8 30 8 3 25.7 59 165 -34 0 10 50 2 6 51 0 9 26 2 8 17 -0.57 - 68 0 0 1 51 41 8 4 7.3 58 167 -33 0 53 28 2 50 35 0 52 4 2 52 1 -0.56 - 67 0 0 2 36 10 8 4 49.0 58 169 -31 1 37 25 3 35 38 1 36 0 3 37 5 -0.56 - 66 0 0 3 21 58 8 5 30.8 57 171 -30 2 22 40 4 22 0 2 21 14 4 23 28 -0.56 - 65 0 0 4 9 4 8 6 12.7 57 173 -28 3 9 11 5 9 40 3 7 45 5 11 9 -0.56 - 64 0 0 4 57 26 8 6 54.6 56 175 -27 3 57 0 5 58 38 3 55 32 6 0 8 -0.55 - 63 0 0 5 47 4 8 7 36.4 55 177 -26 4 46 3 6 48 52 4 44 35 6 50 22 -0.55 - 62 0 0 6 37 57 8 8 18.2 55 179 -24 5 36 21 7 40 20 5 34 52 7 41 51 -0.55 - 61 0 0 7 30 2 8 8 59.8 54 181 -23 6 27 52 8 33 1 6 26 22 8 34 34 -0.55 - 60 0 0 8 23 19 8 9 41.2 53 183 -21 7 20 34 9 26 54 7 19 3 9 28 27 -0.54 - 59 0 0 9 17 45 8 10 22.3 52 184 -20 8 14 25 10 21 55 8 12 53 10 23 29 -0.54 - 58 0 0 10 13 17 8 11 3.1 51 186 -18 9 9 22 11 18 3 9 7 50 11 19 38 -0.54 - 57 0 0 11 9 53 8 11 43.5 50 187 -17 10 5 24 12 15 14 10 3 51 12 16 50 -0.53 - 56 0 0 12 7 29 8 12 23.4 49 189 -15 11 2 27 13 13 26 11 0 53 13 15 2 -0.53 - 55 0 0 13 6 4 8 13 2.8 48 190 -14 12 0 28 14 12 35 11 58 53 14 14 12 -0.53 - 54 0 0 14 5 33 8 13 41.5 46 191 -13 12 59 24 15 12 37 12 57 48 15 14 16 -0.52 - 53 0 0 15 5 52 8 14 19.6 45 192 -11 13 59 11 16 13 29 13 57 34 16 15 8 -0.52 - 52 0 0 16 6 57 8 14 57.0 44 194 -10 14 59 45 17 15 7 14 58 8 17 16 47 -0.52 - 51 0 0 17 8 45 8 15 33.5 43 195 -8 16 1 2 18 17 26 15 59 25 18 19 6 -0.52 - 50 0 0 18 11 10 8 16 9.2 41 196 -7 17 2 59 19 20 21 17 1 20 19 22 2 -0.51 - 49 0 0 19 14 8 8 16 44.0 40 197 -5 18 5 29 20 23 48 18 3 50 20 25 30 -0.51 - 48 0 0 20 17 35 8 17 17.8 39 198 -4 19 8 29 21 27 42 19 6 49 21 29 25 -0.51 - 47 0 0 21 21 24 8 17 50.5 37 199 -3 20 11 53 22 31 58 20 10 13 22 33 41 -0.51 - 46 0 0 22 25 32 8 18 22.1 36 199 -1 21 15 37 23 36 31 21 13 57 23 38 14 -0.51 - 45 0 0 23 29 53 8 18 52.6 35 200 0 22 19 36 24 41 14 22 17 55 24 42 59 -0.51 - 44 0 0 24 34 22 8 19 21.9 33 201 2 23 23 44 25 46 5 23 22 2 25 47 50 -0.50 - 43 0 0 25 38 53 8 19 50.0 32 202 3 24 27 57 26 50 56 24 26 15 26 52 42 -0.50 - 42 0 0 26 43 23 8 20 16.9 31 203 4 25 32 9 27 55 43 25 30 26 27 57 29 -0.50 - 41 0 0 27 47 44 8 20 42.5 29 204 6 26 36 15 29 0 21 26 34 32 29 2 7 -0.50 - 40 0 0 28 51 53 8 21 6.8 28 204 7 27 40 10 30 4 44 27 38 27 30 6 31 -0.50 - 39 0 0 29 55 45 8 21 29.8 26 205 8 28 43 50 31 8 49 28 42 7 31 10 36 -0.50 - 38 0 0 30 59 15 8 21 51.5 25 206 9 29 47 10 32 12 30 29 45 26 32 14 17 -0.50 - 37 0 0 32 2 19 8 22 12.0 24 207 11 30 50 6 33 15 42 30 48 21 33 17 30 -0.50 - 36 0 0 33 4 51 8 22 31.1 22 207 12 31 52 32 34 18 22 31 50 48 34 20 10 -0.50 - 35 0 0 34 6 49 8 22 49.0 21 208 13 32 54 25 35 20 25 32 52 41 35 22 13 -0.50 - 34 0 0 35 8 9 8 23 5.6 20 209 14 33 55 42 36 21 48 33 53 57 36 23 36 -0.50 - 33 0 0 36 8 46 8 23 20.9 19 210 15 34 56 17 37 22 27 34 54 33 37 24 15 -0.50 - 32 0 0 37 8 37 8 23 35.1 17 210 16 35 56 9 38 22 18 35 54 25 38 24 6 -0.50 - 31 0 0 38 7 40 8 23 48.0 16 211 17 36 55 15 39 21 19 36 53 30 39 23 7 -0.50 - 30 0 0 39 5 52 8 23 59.8 15 212 18 37 53 30 40 19 27 37 51 45 40 21 15 -0.50 - 29 0 0 40 3 9 8 24 10.5 13 212 19 38 50 52 41 16 39 38 49 8 41 18 27 -0.50 - 28 0 0 40 59 30 8 24 20.0 12 213 20 39 47 20 42 12 54 39 45 36 42 14 42 -0.50 - 27 0 0 41 54 53 8 24 28.6 11 214 21 40 42 52 43 8 8 40 41 8 43 9 56 -0.50 - 26 0 0 42 49 16 8 24 36.1 10 214 22 41 37 24 44 2 21 41 35 41 44 4 9 -0.51 - 25 0 0 43 42 37 8 24 42.6 9 215 23 42 30 56 44 55 31 42 29 13 44 57 18 -0.51 - 24 0 0 44 34 55 8 24 48.3 8 216 24 43 23 27 45 47 37 43 21 44 45 49 23 -0.51 - 23 0 0 45 26 9 8 24 53.0 6 217 25 44 14 55 46 38 37 44 13 12 46 40 23 -0.51 - 22 0 0 46 16 18 8 24 56.9 5 217 26 45 5 19 47 28 31 45 3 37 47 30 17 -0.51 - 21 0 0 47 5 22 8 25 0.0 4 218 26 45 54 39 48 17 19 45 52 57 48 19 4 -0.52 - 20 0 0 47 53 20 8 25 2.4 3 219 27 46 42 54 49 4 59 46 41 13 49 6 44 -0.52 - 19 0 0 48 40 12 8 25 4.0 2 220 28 47 30 4 49 51 33 47 28 23 49 53 17 -0.53 - 18 0 0 49 25 57 8 25 5.0 1 220 28 48 16 9 50 36 59 48 14 28 50 38 43 -0.55 - 17 0 0 50 10 37 8 25 5.3 0 221 29 49 1 8 .. .. .. 48 59 28 .. .. .. -0.71 - 16 0 0 .. .. .... .. .. .. .. .. .. 49 45 2 .. .. .. 49 43 23 .. .. .. .... Uncertainty in time = +/- 7 secs Prediction of 2023 Apr 29.2 Data for the target star ------------------------ * name: UCAC4 306-279491 * constellation : Microscopium * BCRS position with proper motion to date of event [h,m,s ; °,',"] RA: 20 31 38.4146 DE: -28 52 03.168 * GCRS Astrometric position with proper motion and parallax to date of event [h,m,s ; °,',"] RA: 20 31 38.4147 DE: -28 52 03.168 * position source: Gaia DR3 * standard error: RA,DE [mas]: (0.200,0.100) * V mag [mag]: 12.2 * Diameter [mas]: 0.00 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (54) Alexandra asteroid class: approx. diameter [km]: 152 approx. diameter ["]: 0.144 distance from Earth [AU]: 1.45430 asteroid position offset in RA [mas]: 0 asteroid position offset in DE [mas]: 0 * orbital information: orbit source: JPL#193 date of fit: 2023 Apr 24 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): 0.026", 0.001", 61.685° remarks: * orbital elements for (54)Alexandra : Mean anomaly = 347.9126753975 deg Arg. of pericenter = 345.2791732927 deg Long. of node = 313.2300955048 deg Inclination = 11.7967339637 deg Eccentricity = 0.1967508411 Semimajor axis = 2.7107714797 AU Perihelion dist = 2.1774249111 AU Mag: H = 7.87, G = 0.15 Epoch of elements : MJD 60094.33354167 TDT (2023 May 30.3335) ------ occelmnt file for Occult BEGIN ----------------------------------- JPL#1932023Apr24,41.82,2023,5,30,7.997626,-0.258237,0.430250,1.760512,1.056140,-0.004280,-0.000573,0.000001,0.000000 -59.2757,-28.7879,59.42,21.75,False UCAC4 306-279491,20.52733738,-28.8675468,0.00,12.17,0.00,0.0,0,,20.55116223,-28.7879096,0.46,0.00,0,0,0 54,Alexandra,11.47,152.1,1.4543,0,0,0.809,6.39,,7.6,0 0,347.8390,2023,5,30,345.2792,313.2301,11.7967,0.19675,2.71077,2.17742,7.88,5.0,0.15 1.012,0.0257,0.0013,62,0.0017,Known errors,-1.00,-1,-1,-1 20230530_279491,60063.19 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2023 Apr 29, 04:32 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 stevepr@acm.org