IOTA/IOTA-ES occultation update for (2655) Guangxi / UCAC4 336-085683 event on 2023 Aug 28, 20:14 UT Visible from Europe, Africa Summary ------- On 2023 Aug 28 UT, the 16.5 km diameter asteroid (2655) Guangxi will occult a 11.8 mag star in the constellation Ophiuchus for observers along a path across Europe, Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 6.18 mag to 17.97 mag (the magnitude of the asteroid) for at most 1.710 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: 33 * date and approx. time of event: 2023 Aug 28, 20:08 - 2023 Aug 28, 20:19 * geocentric midpoint of event [JD]: 2460185.34317454 * magnitude of target star: 11.79 * magnitude drop [mag]: 6.18 * estimated maximum duration [s]: 1.710 * Moon: 93 % sunlit, 50° distance * Sun: 99° distance * rough path description: Europe, Africa The occultation path -------------------- * approximate projected width [km]: 35 * 1 sigma uncertainty interval [path widths]: +/- 2.00 * 1 sigma uncertainty interval [seconds]: +/- 4.7 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- 0.017, +/- 0.015) * 1 sigma uncertainty ellipse (major, minor, PA): (0.018", 0.013", 118°) * approx speed of asteroid's shadow [km/s]: 9.6331 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC4 336-085683 by 2655 Guangxi on 2023 Aug 28 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 ' " Longitude Longitude Longitude Longitude .. .. .. 67 0 0 .. .. .... .. .. .. ... .. .. ... .. .. - 21 24 0 ... .. .. .... - 19 41 50 66 0 0 20 8 57.0 1 186 4 - 20 4 28 - 19 19 5 - 21 33 53 - 17 46 38 .... - 19 51 3 65 0 0 20 8 57.6 2 186 4 - 20 12 46 - 19 29 13 - 21 38 38 - 18 0 33 1.24 - 19 55 16 64 0 0 20 8 58.6 3 186 3 - 20 16 10 - 19 34 15 - 21 38 52 - 18 8 58 1.43 - 19 55 1 63 0 0 20 9 0.0 4 186 3 - 20 15 11 - 19 34 44 - 21 35 3 - 18 12 28 -1.53 - 19 50 47 62 0 0 20 9 1.8 5 186 3 - 20 10 18 - 19 31 10 - 21 27 36 - 18 11 36 -1.58 - 19 42 55 61 0 0 20 9 4.1 6 186 2 - 20 1 51 - 19 23 54 - 21 16 50 - 18 6 46 -1.62 - 19 31 45 60 0 0 20 9 6.8 7 186 2 - 19 50 9 - 19 13 16 - 21 3 3 - 17 58 20 -1.65 - 19 17 33 59 0 0 20 9 9.9 8 187 2 - 19 35 28 - 18 59 33 - 20 46 28 - 17 46 37 -1.67 - 19 0 33 58 0 0 20 9 13.5 9 187 1 - 19 18 2 - 18 42 59 - 20 27 18 - 17 31 50 -1.68 - 18 40 54 57 0 0 20 9 17.4 10 187 1 - 18 57 59 - 18 23 44 - 20 5 43 - 17 14 12 -1.69 - 18 18 48 56 0 0 20 9 21.8 11 188 0 - 18 35 32 - 18 1 59 - 19 41 51 - 16 53 55 -1.70 - 17 54 21 55 0 0 20 9 26.7 12 188 0 - 18 10 45 - 17 37 52 - 19 15 48 - 16 31 5 -1.71 - 17 27 40 54 0 0 20 9 32.0 13 189 -1 - 17 43 47 - 17 11 28 - 18 47 41 - 16 5 52 -1.72 - 16 58 50 53 0 0 20 9 37.8 14 189 -1 - 17 14 42 - 16 42 54 - 18 17 35 - 15 38 21 -1.73 - 16 27 56 52 0 0 20 9 44.0 15 190 -2 - 16 43 34 - 16 12 13 - 17 45 32 - 15 8 36 -1.73 - 15 55 0 51 0 0 20 9 50.6 16 190 -3 - 16 10 26 - 15 39 29 - 17 11 36 - 14 36 41 -1.74 - 15 20 4 50 0 0 20 9 57.8 16 191 -3 - 15 35 20 - 15 4 44 - 16 35 47 - 14 2 38 -1.74 - 14 43 10 49 0 0 20 10 5.4 17 192 -4 - 14 58 17 - 14 27 59 - 15 58 9 - 13 26 28 -1.75 - 14 4 18 48 0 0 20 10 13.5 18 192 -5 - 14 19 17 - 13 49 15 - 15 18 39 - 12 48 13 -1.75 - 13 23 28 47 0 0 20 10 22.1 19 193 -6 - 13 38 21 - 13 8 30 - 14 37 19 - 12 7 51 -1.76 - 12 40 37 46 0 0 20 10 31.2 20 194 -6 - 12 55 26 - 12 25 44 - 13 54 5 - 11 25 22 -1.76 - 11 55 45 45 0 0 20 10 40.8 21 195 -7 - 12 10 31 - 11 40 54 - 13 8 57 - 10 40 42 -1.76 - 11 8 46 44 0 0 20 10 51.0 22 196 -8 - 11 23 31 - 10 53 57 - 12 21 51 - 9 53 48 -1.77 - 10 19 39 43 0 0 20 11 1.7 22 197 -9 - 10 34 24 - 10 4 49 - 11 32 44 - 9 4 37 -1.77 - 9 28 16 42 0 0 20 11 12.9 23 198 -10 - 9 43 3 - 9 13 24 - 10 41 29 - 8 13 1 -1.78 - 8 34 31 41 0 0 20 11 24.8 24 199 -11 - 8 49 22 - 8 19 35 - 9 48 2 - 7 18 53 -1.78 - 7 38 16 40 0 0 20 11 37.2 25 200 -12 - 7 53 13 - 7 23 13 - 8 52 15 - 6 22 4 -1.79 - 6 39 21 39 0 0 20 11 50.3 25 201 -13 - 6 54 26 - 6 24 10 - 7 53 58 - 5 22 22 -1.79 - 5 37 33 38 0 0 20 12 4.0 26 202 -15 - 5 52 49 - 5 22 11 - 6 53 1 - 4 19 35 -1.80 - 4 32 39 37 0 0 20 12 18.4 26 203 -16 - 4 48 9 - 4 17 3 - 5 49 11 - 3 13 26 -1.80 - 3 24 21 36 0 0 20 12 33.5 27 205 -17 - 3 40 7 - 3 8 27 - 4 42 12 - 2 3 34 -1.81 - 2 12 17 35 0 0 20 12 49.4 27 206 -19 - 2 28 25 - 1 56 2 - 3 31 47 - 0 49 34 -1.81 - 0 56 0 34 0 0 20 13 6.2 28 208 -20 - 1 12 33 - 0 39 18 - 2 17 31 0 29 7 -1.82 0 25 5 33 0 0 20 13 23.8 28 209 -21 0 8 0 0 42 21 - 0 58 55 1 53 9 -1.83 1 51 42 32 0 0 20 13 42.5 28 211 -23 1 33 58 2 9 38 0 24 37 3 23 27 -1.83 3 24 48 31 0 0 20 14 2.2 28 213 -25 3 6 14 3 43 36 1 53 53 5 1 13 -1.84 5 5 42 30 0 0 20 14 23.3 28 215 -27 4 46 5 5 25 36 3 29 55 6 48 10 -1.85 6 56 16 29 0 0 20 14 45.9 28 217 -29 6 35 16 7 17 37 5 14 8 8 46 51 -1.86 8 59 19 28 0 0 20 15 10.3 28 219 -31 8 36 25 9 22 41 7 8 36 11 1 21 -1.87 Latitude Latitude Latitude Latitude 9 0 0 27 59 42 20 15 10.4 28 219 -31 27 49 6 28 10 21 27 7 20 28 53 46 -1.85 10 0 0 27 32 58 20 15 22.1 28 220 -32 27 22 30 27 43 29 26 41 14 28 26 20 -1.86 11 0 0 27 7 49 20 15 33.5 27 221 -33 26 57 29 27 18 14 26 16 40 28 0 34 -1.86 12 0 0 26 44 15 20 15 44.7 27 222 -34 26 34 2 26 54 33 25 53 39 27 36 24 -1.87 13 0 0 26 22 14 20 15 55.7 27 223 -35 26 12 7 26 32 25 25 32 8 27 13 51 -1.87 14 0 0 26 1 44 20 16 6.5 26 224 -36 25 51 42 26 11 50 25 12 5 26 52 51 -1.87 15 0 0 25 42 44 20 16 17.1 26 224 -37 25 32 47 25 52 44 24 53 30 26 33 23 -1.87 16 0 0 25 25 12 20 16 27.4 25 225 -38 25 15 20 25 35 8 24 36 21 26 15 26 -1.87 17 0 0 25 9 8 20 16 37.5 25 226 -38 24 59 21 25 18 59 24 20 38 25 58 59 -1.87 18 0 0 24 54 30 20 16 47.4 24 227 -39 24 44 47 25 4 17 24 6 20 25 44 0 -1.88 19 0 0 24 41 18 20 16 57.0 24 228 -40 24 31 38 24 51 1 23 53 25 25 30 29 -1.88 20 0 0 24 29 30 20 17 6.4 23 229 -41 24 19 53 24 39 10 23 41 52 25 18 24 -1.88 21 0 0 24 19 6 20 17 15.5 23 229 -42 24 9 32 24 28 43 23 31 42 25 7 45 -1.88 22 0 0 24 10 4 20 17 24.3 22 230 -43 24 0 33 24 19 39 23 22 53 24 58 30 -1.88 23 0 0 24 2 25 20 17 32.8 21 231 -44 23 52 56 24 11 57 23 15 24 24 50 40 -1.88 24 0 0 23 56 7 20 17 41.1 21 231 -44 23 46 40 24 5 37 23 9 15 24 44 12 -1.88 25 0 0 23 51 10 20 17 49.2 20 232 -45 23 41 44 24 0 38 23 4 25 24 39 7 -1.88 26 0 0 23 47 33 20 17 56.9 19 233 -46 23 38 8 23 57 0 23 0 55 24 35 24 -1.88 27 0 0 23 45 16 20 18 4.3 19 233 -46 23 35 53 23 54 43 22 58 42 24 33 2 -1.88 28 0 0 23 44 19 20 18 11.5 18 234 -47 23 34 56 23 53 45 22 57 48 24 32 2 -1.88 29 0 0 23 44 42 20 18 18.3 17 235 -48 23 35 19 23 54 7 22 58 12 24 32 22 -1.88 30 0 0 23 46 23 20 18 24.9 16 235 -48 23 37 0 23 55 48 22 59 54 24 34 3 -1.88 31 0 0 23 49 23 20 18 31.1 15 236 -49 23 40 0 23 58 49 23 2 52 24 37 5 -1.88 32 0 0 23 53 41 20 18 37.0 15 236 -49 23 44 18 24 3 8 23 7 8 24 41 26 -1.88 33 0 0 23 59 18 20 18 42.6 14 237 -50 23 49 54 24 8 45 23 12 41 24 47 8 -1.88 34 0 0 24 6 13 20 18 47.9 13 237 -50 23 56 48 24 15 42 23 19 30 24 54 9 -1.88 35 0 0 24 14 27 20 18 52.9 12 238 -51 24 5 0 24 23 57 23 27 37 25 2 31 -1.89 36 0 0 24 24 0 20 18 57.5 11 238 -51 24 14 31 24 33 32 23 37 1 25 12 13 -1.89 37 0 0 24 34 51 20 19 1.8 10 239 -51 24 25 20 24 44 25 23 47 42 25 23 15 -1.89 38 0 0 24 47 1 20 19 5.7 9 239 -52 24 37 27 24 56 37 23 59 40 25 35 37 -1.90 39 0 0 25 0 29 20 19 9.3 9 240 -52 24 50 53 25 10 9 24 12 55 25 49 20 -1.90 40 0 0 25 15 17 20 19 12.6 8 240 -52 25 5 38 25 25 0 24 27 28 26 4 25 -1.91 41 0 0 25 31 25 20 19 15.5 7 241 -52 25 21 43 25 41 11 24 43 20 26 20 51 -1.92 42 0 0 25 48 53 20 19 18.0 6 241 -52 25 39 7 25 58 43 25 0 29 26 38 39 -1.93 43 0 0 26 7 42 20 19 20.1 5 241 -52 25 57 52 26 17 36 25 18 58 26 57 49 -1.95 44 0 0 26 27 52 20 19 21.9 4 242 -52 26 17 57 26 37 51 25 38 46 27 18 23 -1.98 45 0 0 26 49 24 20 19 23.3 3 242 -52 26 39 23 26 59 27 25 59 53 27 40 21 -2.03 46 0 0 27 12 18 20 19 24.3 2 243 -52 27 2 12 27 22 27 26 22 21 28 3 44 -2.13 47 0 0 27 36 35 20 19 24.8 1 243 -52 27 26 24 27 46 50 26 46 10 28 28 32 -2.44 48 0 0 28 2 16 20 19 25.0 0 244 -52 27 51 59 .. .. .. 27 11 21 .. .. .. -42.63 Uncertainty in time = +/- 5 secs Prediction of 2023 Aug 6.7 Data for the target star ------------------------ * name: UCAC4 336-085683 * constellation : Ophiuchus * BCRS position with proper motion to date of event [h,m,s ; °,',"] RA: 16 49 12.8831 DE: -22 58 53.179 * GCRS Astrometric position with proper motion and parallax to date of event [h,m,s ; °,',"] RA: 16 49 12.8828 DE: -22 58 53.178 * position source: Gaia DR3 * standard error: RA,DE [mas]: (0.200,0.100) * V mag [mag]: 11.8 * Diameter [mas]: 0.00 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (2655) Guangxi asteroid class: approx. diameter [km]: 17 approx. diameter ["]: 0.007 distance from Earth [AU]: 3.41250 asteroid position offset in RA [mas]: 0 asteroid position offset in DE [mas]: 0 * orbital information: orbit source: JPL#54 date of fit: 2023 Jul 30 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", 0.013", 117.626° remarks: * orbital elements for (2655)Guangxi : Mean anomaly = 191.8400133394 deg Arg. of pericenter = 353.0466572530 deg Long. of node = 87.7929122142 deg Inclination = 17.1926361441 deg Eccentricity = 0.1647692491 Semimajor axis = 3.1871724969 AU Perihelion dist = 2.6620244778 AU Mag: H = 11.61, G = 0.15 Epoch of elements : MJD 60184.84312500 TDT (2023 Aug 28.8431) ------ occelmnt file for Occult BEGIN ----------------------------------- JPL#542023Jul30,1.71,2023,8,28,20.236189,0.452994,0.752453,4.661881,-2.798214,0.005649,-0.000663,0.000000,0.000000 -27.6746,-23.0232,-123.23,9.58,False UCAC4 336-085683,16.82024532,-22.9814385,0.00,11.79,0.00,0.0,0,,16.84390797,-23.0232338,6.19,0.00,0,0,0 2655,Guangxi,17.97,16.500,3.4125,0,0,0.871,-7.21,,1.6,0 0,191.6940,2023,8,28,353.0467,87.7929,17.1926,0.16477,3.18717,2.66202,11.61,5.0,0.15 3.003,0.0183,0.0133,118,0.0227,Known errors,-1.00,0,-1,-1 20230828_085683,60162.67 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2023 Aug 06, 16:07 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 stevepr@acm.org