IOTA/IOTA-ES occultation update for (42) Isis / UCAC4 303-191894 event on 2024 Jul 22, 06:19 UT Visible from Summary ------- On 2024 Jul 22 UT, the 113.028 km diameter asteroid (42) Isis 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 0.49 mag to 9.91 mag (the magnitude of the asteroid) for at most 22.790 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 Jul 22, 06:08 - 2024 Jul 22, 06:29 * geocentric midpoint of event [JD]: 2460513.76332575 * magnitude of target star: 10.52 * magnitude drop [mag]: 0.49 * estimated maximum duration [s]: 22.790 * Moon: 99 % sunlit, 38° distance * Sun: 152° distance * rough path description: The occultation path -------------------- * approximate projected width [km]: 264 * 1 sigma uncertainty interval [path widths]: +/- 0.17 * 1 sigma uncertainty interval [seconds]: +/- 4.7 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- 0.040, +/- 0.008) * 1 sigma uncertainty ellipse (major, minor, PA): (0.041", 0.003", 100°) * approx speed of asteroid's shadow [km/s]: 4.9593 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC4 303-191894 by 42 Isis on 2024 Jul 22 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 163 0 0 .. .. .... .. .. .. .. .. .. .. .. .. 28 48 2 .. .. .. 28 18 25 .... 164 0 0 29 40 59 6 28 20.5 0 125 19 .. .. .. 28 12 55 .. .. .. 27 43 55 .... 165 0 0 29 6 4 6 28 19.9 1 125 18 30 38 17 27 39 53 .. .. .. 27 11 28 -0.96 166 0 0 28 33 20 6 28 18.4 2 126 17 30 3 28 27 8 52 30 35 58 26 40 59 -1.55 167 0 0 28 2 41 6 28 15.9 3 126 16 29 30 56 26 39 47 30 2 42 26 12 22 -1.77 168 0 0 27 34 1 6 28 12.6 4 127 15 29 0 34 26 12 32 29 31 40 25 45 33 -1.88 169 0 0 27 7 16 6 28 8.4 5 127 14 28 32 17 25 47 5 29 2 47 25 20 30 -1.94 170 0 0 26 42 22 6 28 3.5 6 127 13 28 5 59 25 23 21 28 35 56 24 57 8 -1.98 171 0 0 26 19 15 6 27 57.8 7 128 12 27 41 36 25 1 18 28 11 4 24 35 24 -2.01 172 0 0 25 57 50 6 27 51.3 8 128 11 27 19 3 24 40 52 27 48 4 24 15 16 -2.03 173 0 0 25 38 5 6 27 44.2 9 129 10 26 58 16 24 22 0 27 26 53 23 56 42 -2.05 174 0 0 25 19 58 6 27 36.4 10 129 9 26 39 12 24 4 41 27 7 28 23 39 38 -2.06 175 0 0 25 3 26 6 27 28.0 11 130 8 26 21 49 23 48 53 26 49 45 23 24 3 -2.06 176 0 0 24 48 26 6 27 18.9 11 130 7 26 6 3 23 34 32 26 33 42 23 9 55 -2.07 177 0 0 24 34 57 6 27 9.3 12 131 6 25 51 53 23 21 39 26 19 16 22 57 12 -2.07 178 0 0 24 22 56 6 26 59.0 13 131 5 25 39 15 23 10 10 26 6 24 22 45 53 -2.08 179 0 0 24 12 22 6 26 48.3 14 132 5 25 28 9 23 0 4 25 55 6 22 35 57 -2.08 -180 0 0 24 3 14 6 26 36.9 15 132 4 25 18 33 22 51 21 25 45 18 22 27 21 -2.08 -179 0 0 23 55 31 6 26 25.1 15 133 3 25 10 24 22 43 59 25 37 0 22 20 6 -2.08 -178 0 0 23 49 10 6 26 12.8 16 133 2 25 3 42 22 37 57 25 30 10 22 14 10 -2.08 -177 0 0 23 44 11 6 26 0.0 17 134 1 24 58 26 22 33 14 25 24 47 22 9 32 -2.08 -176 0 0 23 40 34 6 25 46.7 17 134 0 24 54 34 22 29 49 25 20 50 22 6 11 -2.08 -175 0 0 23 38 17 6 25 32.9 18 135 0 24 52 6 22 27 41 25 18 17 22 4 6 -2.08 -174 0 0 23 37 19 6 25 18.8 19 136 -1 24 51 0 22 26 51 25 17 9 22 3 18 -2.08 -173 0 0 23 37 41 6 25 4.2 19 136 -2 24 51 17 22 27 17 25 17 24 22 3 46 -2.08 -172 0 0 23 39 22 6 24 49.1 20 137 -3 24 52 56 22 29 0 25 19 3 22 5 29 -2.08 -171 0 0 23 42 21 6 24 33.7 20 137 -4 24 55 57 22 31 58 25 22 4 22 8 26 -2.08 -170 0 0 23 46 39 6 24 17.9 21 138 -4 25 0 19 22 36 11 25 26 27 22 12 39 -2.08 -169 0 0 23 52 14 6 24 1.7 21 139 -5 25 6 2 22 41 41 25 32 14 22 18 6 -2.08 -168 0 0 23 59 8 6 23 45.1 22 139 -6 25 13 6 22 48 25 25 39 22 22 24 48 -2.08 -167 0 0 24 7 20 6 23 28.2 22 140 -7 25 21 33 22 56 26 25 47 54 22 32 44 -2.08 -166 0 0 24 16 52 6 23 11.0 23 141 -7 25 31 21 23 5 42 25 57 48 22 41 56 -2.08 -165 0 0 24 27 42 6 22 53.4 23 141 -8 25 42 32 23 16 14 26 9 7 22 52 22 -2.08 -164 0 0 24 39 51 6 22 35.4 23 142 -9 25 55 5 23 28 2 26 21 49 23 4 4 -2.09 -163 0 0 24 53 20 6 22 17.2 24 143 -9 26 9 1 23 41 8 26 35 56 23 17 2 -2.09 -162 0 0 25 8 10 6 21 58.6 24 144 -10 26 24 23 23 55 31 26 51 29 23 31 17 -2.09 -161 0 0 25 24 22 6 21 39.8 24 144 -10 26 41 9 24 11 12 27 8 29 23 46 49 -2.09 -160 0 0 25 41 55 6 21 20.7 25 145 -11 26 59 22 24 28 12 27 26 57 24 3 38 -2.09 -159 0 0 26 0 53 6 21 1.3 25 146 -12 27 19 3 24 46 32 27 46 55 24 21 46 -2.10 -158 0 0 26 21 16 6 20 41.6 25 147 -12 27 40 14 25 6 13 28 8 25 24 41 15 -2.10 -157 0 0 26 43 4 6 20 21.7 25 147 -13 28 2 56 25 27 17 28 31 27 25 2 4 -2.10 -156 0 0 27 6 21 6 20 1.5 25 148 -13 28 27 12 25 49 43 28 56 6 25 24 15 -2.11 -155 0 0 27 31 8 6 19 41.1 25 149 -14 28 53 3 26 13 36 29 22 22 25 47 50 -2.11 -154 0 0 27 57 27 6 19 20.4 25 150 -14 29 20 33 26 38 55 29 50 19 26 12 51 -2.11 -153 0 0 28 25 20 6 18 59.6 25 151 -15 29 49 44 27 5 42 30 20 1 26 39 18 -2.12 -152 0 0 28 54 50 6 18 38.6 25 152 -15 30 20 40 27 34 1 30 51 30 27 7 15 -2.12 -151 0 0 29 26 0 6 18 17.3 25 153 -15 30 53 25 28 3 53 31 24 52 27 36 43 -2.13 -150 0 0 29 58 54 6 17 55.9 25 154 -16 31 28 3 28 35 21 32 0 11 28 7 45 -2.13 -149 0 0 30 33 35 6 17 34.3 25 154 -16 32 4 39 29 8 28 32 37 34 28 40 24 -2.14 -148 0 0 31 10 9 6 17 12.6 25 155 -16 32 43 19 29 43 18 33 17 5 29 14 42 -2.15 -147 0 0 31 48 38 6 16 50.7 24 156 -16 33 24 11 30 19 54 33 58 54 29 50 44 -2.15 -146 0 0 32 29 11 6 16 28.7 24 157 -17 34 7 22 30 58 22 34 43 9 30 28 34 -2.16 -145 0 0 33 11 53 6 16 6.5 24 158 -17 34 53 1 31 38 45 35 30 2 31 8 16 -2.17 -144 0 0 33 56 53 6 15 44.3 23 159 -17 35 41 21 32 21 9 36 19 46 31 49 55 -2.18 -143 0 0 34 44 19 6 15 22.0 23 160 -17 36 32 35 33 5 42 37 12 37 32 33 37 -2.19 -142 0 0 35 34 23 6 14 59.5 22 161 -17 37 27 1 33 52 31 38 8 56 33 19 30 -2.20 -141 0 0 36 27 18 6 14 37.1 22 162 -17 38 25 0 34 41 46 39 9 9 34 7 41 -2.21 -140 0 0 37 23 21 6 14 14.6 21 163 -17 39 27 0 35 33 36 40 13 50 34 58 20 -2.22 -139 0 0 38 22 52 6 13 52.0 20 164 -17 40 33 38 36 28 15 41 23 49 35 51 38 -2.23 -138 0 0 39 26 18 6 13 29.5 19 165 -17 41 45 47 37 25 59 42 40 13 36 47 49 -2.24 -137 0 0 40 34 14 6 13 6.9 18 165 -16 43 4 40 38 27 8 44 4 47 37 47 10 -2.26 -136 0 0 41 47 26 6 12 44.3 17 166 -16 44 32 13 39 32 7 45 40 28 38 50 2 -2.27 -135 0 0 43 7 4 6 12 21.7 16 167 -15 46 11 46 40 41 29 47 32 56 39 56 52 -2.29 -134 0 0 44 34 48 6 11 59.0 15 168 -15 48 10 1 41 55 59 49 56 54 41 8 16 -2.31 -133 0 0 46 13 31 6 11 36.3 14 169 -14 50 46 1 43 16 39 .. .. .. 42 25 1 -2.34 -132 0 0 48 8 40 6 11 13.2 12 170 -13 .. .. .. 44 45 4 .. .. .. 43 48 18 -2.39 -131 0 0 50 33 47 6 10 49.3 9 171 -11 .. .. .. 46 23 46 .. .. .. 45 19 51 -2.49 -130 0 0 54 52 48 6 10 20.2 5 172 -8 .. .. .. 48 17 25 .. .. .. 47 2 36 -3.10 Uncertainty in time = +/- 6 secs Prediction of 2023 Jul 15.2 Data for the target star ------------------------ * name: UCAC4 303-191894 * constellation : Sagittarius * BCRS position with proper motion to date of event [h,m,s ; °,',"] RA: 18 08 53.4869 DE: -29 35 13.166 * GCRS Astrometric position with proper motion and parallax to date of event [h,m,s ; °,',"] RA: 18 08 53.4868 DE: -29 35 13.166 * position source: Gaia DR3 * standard error: RA,DE [mas]: (0.200,0.200) * V mag [mag]: 10.5 * B mag [mag]: 10.8 * Diameter [mas]: 0.00 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (42) Isis asteroid class: Barbarian approx. diameter [km]: 113 approx. diameter ["]: 0.154 distance from Earth [AU]: 1.01180 asteroid position offset in RA [mas]: 0 asteroid position offset in DE [mas]: 0 * orbital information: orbit source: JPL#120 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): 0.041", 0.003", 99.936° remarks: * orbital elements for (42)Isis : Mean anomaly = 337.5440288677 deg Arg. of pericenter = 237.2516685885 deg Long. of node = 84.1659207388 deg Inclination = 8.5112131414 deg Eccentricity = 0.2220321543 Semimajor axis = 2.4427144661 AU Perihelion dist = 1.9003533108 AU Mag: H = 7.61, G = 0.15 Epoch of elements : MJD 60513.26332667 TDT (2024 Jul 22.2633) ------ occelmnt file for Occult BEGIN ----------------------------------- JPL#1202023Apr24,22.79,2024,7,22,6.319818,-0.452927,0.781755,-2.421734,-1.403727,0.002304,0.000521,0.000001,0.000000 -122.6752,-29.5838,86.83,20.16,False UCAC4 303-191894,18.14819083,-29.5869905,10.78,10.52,10.38,0.0,0,,18.17468300,-29.5838252,0.49,0.39,0,0,0 42,Isis,9.91,113.028,1.0118,0,0,-1.612,-12.20,,6.0,0 0,337.4760,2024,7,22,237.2517,84.1659,8.5112,0.22203,2.44271,1.90035,7.61,5.0,0.15 1.172,0.0410,0.0027,100,0.0265,Known errors,0.61,0,-1,-1 20240722_191894,60140.21 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2023 Jul 15, 05:07 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 stevepr@acm.org