IOTA/IOTA-ES occultation update for (18) Melpomene / UCAC2 25822772 event on 2012 Sep 10, 21:34 UT Visible from S Africa, NE Brazil Summary ------- On 2012 Sep 10 UT, the 140 km diameter asteroid (18) Melpomene will occult a 11.6 mag star in the constellation Sagittarius for observers along a path across S Africa, NE Brazil. In the case of an occultation, the combined light of the asteroid and the star will drop by 0.3 mag to 10.4 mag (the magnitude of the asteroid) for at most 11.1 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: 64 * date and approx. time of event: 2012 Sep 10, 21:33 - 2012 Sep 10, 21:43 UT * geocentric midpoint of event [JD]: 2456181.39930833 * magnitude of target star: 11.6 * magnitude drop [mag]: 0.3 * estimated maximum duration [s]: 11.1 * Moon: 28 % sunlit, 163° distance * Sun: 100° distance * rough path description: S Africa, NE Brazil The occultation path -------------------- * approximate projected width [km]: 140 * 1 sigma uncertainty interval [path widths]: +/- 0.94 * 1 sigma uncertainty interval [seconds]: +/- 10.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .106 +/- .106) * 1 sigma uncertainty ellipse (major, minor, PA): ( .106", .106", 90° ) * approx speed of asteroid's shadow [km/s]: 12.6615 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC2 25822772 by 18 Melpomene on 2012 Sep 10 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 ' " Latitude Latitude Latitude Latitude - 54 0 0 - 7 30 14 21 33 16 77 136 -1 - 8 13 47 - 6 46 39 - 9 35 32 - 5 24 35 - 53 0 0 - 8 3 25 21 33 26 79 138 -2 - 8 46 52 - 7 19 56 -10 8 27 - 5 58 2 - 52 0 0 - 8 36 15 21 33 36 80 140 -3 - 9 19 36 - 7 52 52 -10 41 0 - 6 31 9 - 51 0 0 - 9 8 42 21 33 46 81 142 -4 - 9 51 57 - 8 25 25 -11 13 10 - 7 3 54 - 50 0 0 - 9 40 47 21 33 56 82 145 -5 -10 23 55 - 8 57 36 -11 44 56 - 7 36 16 - 49 0 0 -10 12 27 21 34 6 83 149 -6 -10 55 29 - 9 29 22 -12 16 18 - 8 8 15 - 48 0 0 -10 43 43 21 34 16 84 155 -7 -11 26 39 -10 0 45 -12 47 15 - 8 39 49 - 47 0 0 -11 14 33 21 34 26 85 162 -8 -11 57 22 -10 31 42 -13 17 46 - 9 10 59 - 46 0 0 -11 44 58 21 34 36 85 172 -9 -12 27 40 -11 2 13 -13 47 51 - 9 41 43 - 45 0 0 -12 14 56 21 34 46 86 185 -10 -12 57 31 -11 32 18 -14 17 29 -10 12 1 - 44 0 0 -12 44 26 21 34 56 86 200 -11 -13 26 54 -12 1 55 -14 46 39 -10 41 52 - 43 0 0 -13 13 29 21 35 6 86 216 -12 -13 55 50 -12 31 5 -15 15 22 -11 11 15 - 42 0 0 -13 42 4 21 35 16 86 231 -13 -14 24 18 -12 59 47 -15 43 36 -11 40 10 - 41 0 0 -14 10 10 21 35 26 85 242 -14 -14 52 16 -13 28 0 -16 11 21 -12 8 37 - 40 0 0 -14 37 46 21 35 35 84 251 -15 -15 19 46 -13 55 44 -16 38 37 -12 36 34 - 39 0 0 -15 4 53 21 35 45 83 257 -16 -15 46 45 -14 22 58 -17 5 23 -13 4 2 - 38 0 0 -15 31 30 21 35 55 82 262 -17 -16 13 15 -14 49 43 -17 31 39 -13 31 1 - 37 0 0 -15 57 37 21 36 4 82 266 -18 -16 39 15 -15 15 57 -17 57 25 -13 57 29 - 36 0 0 -16 23 13 21 36 14 81 268 -19 -17 4 44 -15 41 41 -18 22 40 -14 23 26 - 35 0 0 -16 48 19 21 36 23 80 271 -20 -17 29 42 -16 6 53 -18 47 24 -14 48 53 - 34 0 0 -17 12 53 21 36 32 79 272 -21 -17 54 9 -16 31 35 -19 11 37 -15 13 48 - 33 0 0 -17 36 56 21 36 41 78 274 -22 -18 18 4 -16 55 45 -19 35 19 -15 38 12 - 32 0 0 -18 0 27 21 36 51 77 275 -23 -18 41 28 -17 19 24 -19 58 30 -16 2 4 - 31 0 0 -18 23 27 21 37 0 76 276 -24 -19 4 21 -17 42 30 -20 21 9 -16 25 24 - 30 0 0 -18 45 55 21 37 9 75 276 -25 -19 26 42 -18 5 5 -20 43 17 -16 48 13 - 29 0 0 -19 7 51 21 37 17 74 277 -26 -19 48 31 -18 27 8 -21 4 52 -17 10 29 - 28 0 0 -19 29 15 21 37 26 73 277 -27 -20 9 48 -18 48 39 -21 25 56 -17 32 13 - 27 0 0 -19 50 6 21 37 35 72 278 -28 -20 30 33 -19 9 38 -21 46 28 -17 53 24 - 26 0 0 -20 10 26 21 37 43 70 278 -29 -20 50 45 -19 30 4 -22 6 29 -18 14 4 - 25 0 0 -20 30 13 21 37 52 69 278 -30 -21 10 26 -19 49 58 -22 25 57 -18 34 10 - 24 0 0 -20 49 28 21 38 0 68 278 -31 -21 29 35 -20 9 20 -22 44 53 -18 53 44 - 23 0 0 -21 8 11 21 38 9 67 278 -32 -21 48 11 -20 28 9 -23 3 17 -19 12 46 - 22 0 0 -21 26 22 21 38 17 66 278 -33 -22 6 15 -20 46 26 -23 21 10 -19 31 15 - 21 0 0 -21 44 0 21 38 25 65 278 -34 -22 23 47 -21 4 10 -23 38 30 -19 49 11 - 20 0 0 -22 1 6 21 38 33 65 278 -34 -22 40 47 -21 21 23 -23 55 19 -20 6 34 - 19 0 0 -22 17 40 21 38 41 64 278 -35 -22 57 16 -21 38 3 -24 11 36 -20 23 25 - 18 0 0 -22 33 42 21 38 49 63 278 -36 -23 13 12 -21 54 10 -24 27 22 -20 39 44 - 17 0 0 -22 49 12 21 38 56 62 278 -37 -23 28 36 -22 9 46 -24 42 35 -20 55 30 - 16 0 0 -23 4 10 21 39 4 61 277 -38 -23 43 28 -22 24 49 -24 57 17 -21 10 44 - 15 0 0 -23 18 35 21 39 11 60 277 -39 -23 57 49 -22 39 20 -25 11 28 -21 25 25 - 14 0 0 -23 32 29 21 39 19 59 277 -40 -24 11 37 -22 53 19 -25 25 7 -21 39 34 - 13 0 0 -23 45 52 21 39 26 58 277 -41 -24 24 55 -23 6 46 -25 38 15 -21 53 10 - 12 0 0 -23 58 42 21 39 33 57 277 -41 -24 37 40 -23 19 42 -25 50 52 -22 6 15 - 11 0 0 -24 11 1 21 39 40 56 276 -42 -24 49 55 -23 32 5 -26 2 57 -22 18 47 - 10 0 0 -24 22 49 21 39 47 55 276 -43 -25 1 38 -23 43 57 -26 14 32 -22 30 48 - 9 0 0 -24 34 5 21 39 54 54 276 -44 -25 12 50 -23 55 18 -26 25 36 -22 42 16 - 8 0 0 -24 44 49 21 40 1 53 275 -45 -25 23 30 -24 6 7 -26 36 9 -22 53 13 - 7 0 0 -24 55 3 21 40 7 52 275 -46 -25 33 40 -24 16 24 -26 46 11 -23 3 38 - 6 0 0 -25 4 45 21 40 14 51 275 -46 -25 43 19 -24 26 10 -26 55 43 -23 13 31 - 5 0 0 -25 13 57 21 40 20 50 274 -47 -25 52 26 -24 35 25 -27 4 44 -23 22 53 - 4 0 0 -25 22 37 21 40 27 49 274 -48 -26 1 4 -24 44 9 -27 13 15 -23 31 43 - 3 0 0 -25 30 47 21 40 33 48 274 -49 -26 9 10 -24 52 22 -27 21 15 -23 40 2 - 2 0 0 -25 38 26 21 40 39 47 273 -50 -26 16 46 -25 0 4 -27 28 46 -23 47 50 - 1 0 0 -25 45 34 21 40 45 46 273 -50 -26 23 52 -25 7 15 -27 35 46 -23 55 6 0 0 0 -25 52 12 21 40 51 45 273 -51 -26 30 27 -25 13 56 -27 42 16 -24 1 52 1 0 0 -25 58 20 21 40 56 45 272 -52 -26 36 32 -25 20 5 -27 48 17 -24 8 6 2 0 0 -26 3 57 21 41 2 44 272 -53 -26 42 7 -25 25 45 -27 53 47 -24 13 50 3 0 0 -26 9 3 21 41 8 43 271 -53 -26 47 11 -25 30 53 -27 58 48 -24 19 2 4 0 0 -26 13 40 21 41 13 42 271 -54 -26 51 46 -25 35 32 -28 3 20 -24 23 44 5 0 0 -26 17 46 21 41 19 41 271 -55 -26 55 51 -25 39 40 -28 7 21 -24 27 55 6 0 0 -26 21 23 21 41 24 40 270 -56 -26 59 26 -25 43 18 -28 10 54 -24 31 36 7 0 0 -26 24 29 21 41 29 39 270 -56 -27 2 31 -25 46 25 -28 13 56 -24 34 46 8 0 0 -26 27 5 21 41 34 38 269 -57 -27 5 6 -25 49 3 -28 16 30 -24 37 25 9 0 0 -26 29 12 21 41 39 37 269 -58 -27 7 12 -25 51 10 -28 18 34 -24 39 35 10 0 0 -26 30 49 21 41 44 36 269 -58 -27 8 48 -25 52 48 -28 20 9 -24 41 13 11 0 0 -26 31 56 21 41 48 35 268 -59 -27 9 55 -25 53 55 -28 21 15 -24 42 22 12 0 0 -26 32 33 21 41 53 34 268 -60 -27 10 32 -25 54 33 -28 21 51 -24 43 0 13 0 0 -26 32 41 21 41 57 34 267 -60 -27 10 39 -25 54 41 -28 21 59 -24 43 8 14 0 0 -26 32 19 21 42 2 33 267 -61 -27 10 18 -25 54 19 -28 21 37 -24 42 46 15 0 0 -26 31 28 21 42 6 32 266 -62 -27 9 27 -25 53 27 -28 20 47 -24 41 54 16 0 0 -26 30 7 21 42 10 31 266 -62 -27 8 6 -25 52 6 -28 19 27 -24 40 31 17 0 0 -26 28 16 21 42 14 30 266 -63 -27 6 16 -25 50 14 -28 17 39 -24 38 39 18 0 0 -26 25 56 21 42 18 29 265 -64 -27 3 57 -25 47 54 -28 15 21 -24 36 16 19 0 0 -26 23 7 21 42 22 28 265 -64 -27 1 9 -25 45 3 -28 12 35 -24 33 24 20 0 0 -26 19 48 21 42 26 27 264 -65 -26 57 51 -25 41 43 -28 9 19 -24 30 1 21 0 0 -26 16 0 21 42 30 26 264 -65 -26 54 4 -25 37 53 -28 5 35 -24 26 9 22 0 0 -26 11 42 21 42 33 25 263 -66 -26 49 48 -25 33 34 -28 1 22 -24 21 47 23 0 0 -26 6 55 21 42 36 24 263 -66 -26 45 3 -25 28 45 -27 56 40 -24 16 54 24 0 0 -26 1 38 21 42 40 23 263 -67 -26 39 48 -25 23 26 -27 51 29 -24 11 32 25 0 0 -25 55 52 21 42 43 23 262 -67 -26 34 4 -25 17 38 -27 45 49 -24 5 40 26 0 0 -25 49 37 21 42 46 22 262 -68 -26 27 51 -25 11 20 -27 39 41 -23 59 18 27 0 0 -25 42 52 21 42 49 21 261 -68 -26 21 9 -25 4 33 -27 33 3 -23 52 26 28 0 0 -25 35 37 21 42 52 20 261 -68 -26 13 57 -24 57 16 -27 25 56 -23 45 4 29 0 0 -25 27 54 21 42 54 19 260 -69 -26 6 16 -24 49 30 -27 18 21 -23 37 12 30 0 0 -25 19 41 21 42 57 18 260 -69 -25 58 6 -24 41 14 -27 10 16 -23 28 50 31 0 0 -25 10 58 21 42 59 17 260 -69 -25 49 27 -24 32 28 -27 1 43 -23 19 59 32 0 0 -25 1 46 21 43 2 16 259 -70 -25 40 18 -24 23 13 -26 52 41 -23 10 37 33 0 0 -24 52 5 21 43 4 15 259 -70 -25 30 40 -24 13 28 -26 43 9 -23 0 46 34 0 0 -24 41 54 21 43 6 14 258 -70 -25 20 33 -24 3 13 -26 33 9 -22 50 24 35 0 0 -24 31 13 21 43 8 13 258 -70 -25 9 56 -23 52 29 -26 22 39 -22 39 33 36 0 0 -24 20 4 21 43 10 12 258 -70 -24 58 50 -23 41 15 -26 11 41 -22 28 12 37 0 0 -24 8 24 21 43 12 11 257 -70 -24 47 15 -23 29 32 -26 0 13 -22 16 21 38 0 0 -23 56 16 21 43 13 11 257 -70 -24 35 11 -23 17 19 -25 48 17 -22 4 0 39 0 0 -23 43 37 21 43 15 10 256 -70 -24 22 37 -23 4 36 -25 35 51 -21 51 9 40 0 0 -23 30 30 21 43 16 9 256 -70 -24 9 34 -22 51 24 -25 22 56 -21 37 48 41 0 0 -23 16 52 21 43 17 8 256 -70 -23 56 1 -22 37 42 -25 9 33 -21 23 58 42 0 0 -23 2 46 21 43 18 7 255 -70 -23 41 59 -22 23 31 -24 55 40 -21 9 37 43 0 0 -22 48 10 21 43 19 6 255 -70 -23 27 28 -22 8 50 -24 41 18 -20 54 47 44 0 0 -22 33 4 21 43 20 5 254 -69 -23 12 28 -21 53 40 -24 26 27 -20 39 28 45 0 0 -22 17 30 21 43 21 4 254 -69 -22 56 58 -21 38 0 -24 11 6 -20 23 38 46 0 0 -22 1 26 21 43 21 3 254 -69 -22 40 59 -21 21 50 -23 55 17 -20 7 19 47 0 0 -21 44 52 21 43 21 2 253 -68 -22 24 31 -21 5 12 -23 38 59 -19 50 31 48 0 0 -21 27 50 21 43 22 1 253 -68 -22 7 34 -20 48 4 -23 22 12 -19 33 12 Uncertainty in time = +/- 10 secs Prediction of 2012 Sep 8.0 Data for the target star ------------------------ * name: UCAC2 25822772 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 17 53 52.3255 DE: -16 18 21.178 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .106, .106 ) * V mag [mag]: 11.6 * B mag [mag]: 0.0 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (18) Melpomene approx. diameter [km]: 140 approx. diameter ["]: .113 distance from Earth [AU]: 1.70400 * orbital information: orbit source: Preston date of fit: 2012 Sep 07 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 3922 number of rejected observations: 307 time covered by the observations: 1901 Aug 14 - 2012 Aug 30 1 sigma uncertainty ellipse (major, minor, PA): 0.010, 0.008, 99° remarks: * orbital elements for (18) Melpomene : Mean anomaly = 301.62140799 deg Arg. of pericenter = 227.99226963 deg Long. of node = 150.49608728 deg Inclination = 10.12743046 deg Eccentricity = 0.21811382 Semimajor axis = 2.29571974 AU Perihelion dist = 1.79499155 AU Mag: H = 6.54, G = 0.25 Epoch of elements : MJD 56180.89900000 TDT (2012 Sep 10.899) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 10 18 Melpomene 21h 35.0m UT 11.6 17 53 52.326-16 18 21.18UCAC2 25822772 0.0 10.4 140 11.1 1.704 2.306 -16.08 -45.6023 -16.301 -144.58 4.52 21.5834 0.03104 0.06001 6.43092 -3.11700 0.00524 -0.00017 2000 301.3666752012 910.00000227.992270150.496087 10.1274300.21811382 2.2957197 1.7949915 6.5 5.00.25 RATE 2.8335170 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.106 0.106 90 1.94 0.106 0 0-5 2 056178.0020120910_822772 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Sep 07, 22:43 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org