IOTA/IOTA-ES occultation update for (20) Massalia / UCAC2 23002514 event on 2012 Oct 13, 20:43 UT Visible from Africa Summary ------- On 2012 Oct 13 UT, the 132 km diameter asteroid (20) Massalia will occult a 11.6 mag star in the constellation Sagittarius for observers along a path across Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 0.8 mag to 11.7 mag (the magnitude of the asteroid) for at most 6.7 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC. The event at a glimpse ---------------------- * Rank: 94 * date and approx. time of event: 2012 Oct 13, 20:43 - 2012 Oct 13, 20:48 UT * geocentric midpoint of event [JD]: 2456214.36335 * magnitude of target star: 11.6 * magnitude drop [mag]: 0.8 * estimated maximum duration [s]: 6.7 * Moon: 4 % sunlit, 105° distance * Sun: 83° distance * rough path description: Africa The occultation path -------------------- * approximate projected width [km]: 139 * 1 sigma uncertainty interval [path widths]: +/- 0.45 * 1 sigma uncertainty interval [seconds]: +/- 4.2 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .046 +/- .030) * 1 sigma uncertainty ellipse (major, minor, PA): ( .046", .030", 90° ) * approx speed of asteroid's shadow [km/s]: 19.5631 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC2 23002514 by 20 Massalia on 2012 Oct 13 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 - 37 0 0 -39 3 42 20 43 57 70 325 -1 -39 41 53 -38 25 39 -40 16 22 -37 51 32 - 36 0 0 -38 55 24 20 44 2 70 322 -1 -39 33 38 -38 17 19 -40 8 9 -37 43 9 - 35 0 0 -38 46 46 20 44 6 69 320 -2 -39 25 3 -38 8 38 -39 59 37 -37 34 25 - 34 0 0 -38 37 47 20 44 11 69 317 -3 -39 16 7 -37 59 36 -39 50 44 -37 25 21 - 33 0 0 -38 28 28 20 44 15 68 315 -4 -39 6 51 -37 50 14 -39 41 31 -37 15 56 - 32 0 0 -38 18 49 20 44 20 68 313 -5 -38 57 15 -37 40 31 -39 31 57 -37 6 11 - 31 0 0 -38 8 49 20 44 24 68 310 -6 -38 47 18 -37 30 28 -39 22 4 -36 56 5 - 30 0 0 -37 58 29 20 44 29 67 308 -6 -38 37 1 -37 20 5 -39 11 50 -36 45 38 - 29 0 0 -37 47 48 20 44 33 66 306 -7 -38 26 24 -37 9 20 -39 1 15 -36 34 51 - 28 0 0 -37 36 46 20 44 38 66 304 -8 -38 15 26 -36 58 15 -38 50 21 -36 23 43 - 27 0 0 -37 25 25 20 44 42 65 302 -9 -38 4 7 -36 46 50 -38 39 6 -36 12 14 - 26 0 0 -37 13 42 20 44 47 65 300 -10 -37 52 29 -36 35 4 -38 27 30 -36 0 25 - 25 0 0 -37 1 40 20 44 52 64 298 -10 -37 40 30 -36 22 58 -38 15 35 -35 48 16 - 24 0 0 -36 49 16 20 44 56 64 297 -11 -37 28 10 -36 10 31 -38 3 19 -35 35 45 - 23 0 0 -36 36 33 20 45 1 63 295 -12 -37 15 31 -35 57 44 -37 50 42 -35 22 55 - 22 0 0 -36 23 29 20 45 5 62 293 -13 -37 2 31 -35 44 36 -37 37 46 -35 9 44 - 21 0 0 -36 10 5 20 45 10 62 292 -14 -36 49 10 -35 31 8 -37 24 29 -34 56 12 - 20 0 0 -35 56 20 20 45 14 61 290 -15 -36 35 30 -35 17 20 -37 10 52 -34 42 20 - 19 0 0 -35 42 16 20 45 19 60 289 -16 -36 21 29 -35 3 11 -36 56 55 -34 28 8 - 18 0 0 -35 27 51 20 45 23 59 287 -16 -36 7 8 -34 48 42 -36 42 38 -34 13 36 - 17 0 0 -35 13 6 20 45 27 59 286 -17 -35 52 27 -34 33 53 -36 28 0 -33 58 44 - 16 0 0 -34 58 1 20 45 32 58 285 -18 -35 37 26 -34 18 44 -36 13 3 -33 43 31 - 15 0 0 -34 42 36 20 45 36 57 283 -19 -35 22 5 -34 3 16 -35 57 46 -33 27 59 - 14 0 0 -34 26 51 20 45 41 57 282 -20 -35 6 25 -33 47 27 -35 42 9 -33 12 6 - 13 0 0 -34 10 47 20 45 45 56 281 -21 -34 50 24 -33 31 18 -35 26 12 -32 55 54 - 12 0 0 -33 54 23 20 45 50 55 280 -22 -34 34 4 -33 14 50 -35 9 56 -32 39 23 - 11 0 0 -33 37 39 20 45 54 54 279 -23 -34 17 25 -32 58 3 -34 53 20 -32 22 32 - 10 0 0 -33 20 36 20 45 58 53 277 -23 -34 0 26 -32 40 56 -34 36 25 -32 5 21 - 9 0 0 -33 3 14 20 46 3 53 276 -24 -33 43 8 -32 23 30 -34 19 11 -31 47 52 - 8 0 0 -32 45 33 20 46 7 52 275 -25 -33 25 31 -32 5 45 -34 1 37 -31 30 3 - 7 0 0 -32 27 33 20 46 11 51 274 -26 -33 7 35 -31 47 41 -33 43 45 -31 11 56 - 6 0 0 -32 9 15 20 46 15 50 273 -27 -32 49 20 -31 29 19 -33 25 34 -30 53 30 - 5 0 0 -31 50 38 20 46 19 49 272 -28 -32 30 47 -31 10 38 -33 7 4 -30 34 46 - 4 0 0 -31 31 43 20 46 24 48 271 -29 -32 11 56 -30 51 39 -32 48 17 -30 15 43 - 3 0 0 -31 12 30 20 46 28 48 271 -30 -31 52 47 -30 32 22 -32 29 11 -29 56 23 - 2 0 0 -30 52 59 20 46 32 47 270 -31 -31 33 19 -30 12 47 -32 9 47 -29 36 45 - 1 0 0 -30 33 10 20 46 36 46 269 -31 -31 13 35 -29 52 55 -31 50 6 -29 16 50 0 0 0 -30 13 5 20 46 40 45 268 -32 -30 53 33 -29 32 46 -31 30 7 -28 56 38 1 0 0 -29 52 42 20 46 44 44 267 -33 -30 33 14 -29 12 20 -31 9 51 -28 36 8 2 0 0 -29 32 3 20 46 48 43 266 -34 -30 12 38 -28 51 38 -30 49 18 -28 15 23 3 0 0 -29 11 7 20 46 52 42 266 -35 -29 51 46 -28 30 39 -30 28 29 -27 54 21 4 0 0 -28 49 56 20 46 55 41 265 -36 -29 30 38 -28 9 24 -30 7 24 -27 33 4 5 0 0 -28 28 29 20 46 59 40 264 -37 -29 9 14 -27 47 54 -29 46 3 -27 11 31 6 0 0 -28 6 47 20 47 3 39 264 -38 -28 47 35 -27 26 9 -29 24 27 -26 49 43 7 0 0 -27 44 50 20 47 7 39 263 -39 -28 25 41 -27 4 9 -29 2 36 -26 27 40 8 0 0 -27 22 38 20 47 10 38 262 -40 -28 3 32 -26 41 54 -28 40 30 -26 5 23 9 0 0 -27 0 13 20 47 14 37 262 -41 -27 41 9 -26 19 26 -28 18 9 -25 42 53 10 0 0 -26 37 33 20 47 17 36 261 -42 -27 18 33 -25 56 44 -27 55 35 -25 20 9 11 0 0 -26 14 41 20 47 21 35 260 -43 -26 55 43 -25 33 50 -27 32 48 -24 57 12 12 0 0 -25 51 36 20 47 24 34 260 -44 -26 32 40 -25 10 42 -27 9 47 -24 34 2 13 0 0 -25 28 19 20 47 27 33 259 -44 -26 9 25 -24 47 23 -26 46 34 -24 10 41 14 0 0 -25 4 50 20 47 30 32 259 -45 -25 45 59 -24 23 52 -26 23 9 -23 47 8 15 0 0 -24 41 10 20 47 33 31 258 -46 -25 22 20 -24 0 10 -25 59 33 -23 23 24 16 0 0 -24 17 19 20 47 36 30 258 -47 -24 58 31 -23 36 17 -25 35 46 -22 59 30 17 0 0 -23 53 18 20 47 39 29 257 -48 -24 34 32 -23 12 15 -25 11 48 -22 35 26 18 0 0 -23 29 8 20 47 42 28 256 -49 -24 10 23 -22 48 3 -24 47 40 -22 11 13 19 0 0 -23 4 48 20 47 45 27 256 -50 -23 46 5 -22 23 42 -24 23 23 -21 46 50 20 0 0 -22 40 20 20 47 48 26 256 -51 -23 21 38 -21 59 12 -23 58 58 -21 22 20 21 0 0 -22 15 44 20 47 50 25 255 -52 -22 57 3 -21 34 35 -23 34 24 -20 57 42 22 0 0 -21 51 1 20 47 53 24 255 -53 -22 32 21 -21 9 51 -23 9 42 -20 32 57 23 0 0 -21 26 11 20 47 55 23 254 -54 -22 7 32 -20 45 1 -22 44 54 -20 8 6 24 0 0 -21 1 15 20 47 58 22 254 -55 -21 42 36 -20 20 4 -22 19 59 -19 43 9 25 0 0 -20 36 13 20 48 0 21 253 -55 -21 17 35 -19 55 2 -21 54 58 -19 18 7 26 0 0 -20 11 7 20 48 2 20 253 -56 -20 52 29 -19 29 55 -21 29 52 -18 53 0 27 0 0 -19 45 56 20 48 4 19 253 -57 -20 27 19 -19 4 45 -21 4 42 -18 27 49 28 0 0 -19 20 42 20 48 6 18 252 -58 -20 2 4 -18 39 31 -20 39 28 -18 2 35 29 0 0 -18 55 25 20 48 8 17 252 -59 -19 36 47 -18 14 14 -20 14 10 -17 37 19 30 0 0 -18 30 6 20 48 10 16 252 -60 -19 11 28 -17 48 55 -19 48 50 -17 12 0 31 0 0 -18 4 45 20 48 11 15 251 -61 -18 46 6 -17 23 35 -19 23 29 -16 46 40 32 0 0 -17 39 24 20 48 13 14 251 -61 -18 20 44 -16 58 14 -18 58 6 -16 21 20 33 0 0 -17 14 1 20 48 14 12 251 -62 -17 55 21 -16 32 53 -18 32 42 -15 56 0 34 0 0 -16 48 40 20 48 16 11 250 -63 -17 29 58 -16 7 32 -18 7 18 -15 30 40 35 0 0 -16 23 19 20 48 17 10 250 -64 -17 4 36 -15 42 13 -17 41 55 -15 5 21 36 0 0 -15 58 0 20 48 18 9 250 -65 -16 39 16 -15 16 55 -17 16 34 -14 40 5 37 0 0 -15 32 44 20 48 19 8 249 -65 -16 13 58 -14 51 40 -16 51 15 -14 14 51 38 0 0 -15 7 30 20 48 20 7 249 -66 -15 48 43 -14 26 28 -16 25 58 -13 49 40 39 0 0 -14 42 20 20 48 20 6 249 -67 -15 23 31 -14 1 20 -16 0 45 -13 24 34 40 0 0 -14 17 15 20 48 21 5 249 -67 -14 58 24 -13 36 16 -15 35 36 -12 59 32 41 0 0 -13 52 14 20 48 22 4 248 -68 -14 33 21 -13 11 17 -15 10 31 -12 34 35 42 0 0 -13 27 19 20 48 22 3 248 -68 -14 8 24 -12 46 25 -14 45 32 -12 9 44 43 0 0 -13 2 30 20 48 22 2 248 -69 -13 43 33 -12 21 38 -14 20 39 -11 44 59 44 0 0 -12 37 49 20 48 22 1 248 -69 -13 18 49 -11 56 58 -13 55 53 -11 20 22 Uncertainty in time = +/- 5 secs Prediction of 2012 Oct 8.0 Data for the target star ------------------------ * name: UCAC2 23002514 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 58 12.9880 DE: -22 02 41.052 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .045, .030 ) * V mag [mag]: 11.6 * B mag [mag]: 0.0 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (20) Massalia approx. diameter [km]: 132 approx. diameter ["]: .068 distance from Earth [AU]: 2.65900 * orbital information: orbit source: Preston date of fit: 2012 Oct 07 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 1542 number of rejected observations: 254 time covered by the observations: 1900 Jul 17 - 2012 Sep 30 1 sigma uncertainty ellipse (major, minor, PA): 0.007, 0.006, 84° remarks: * orbital elements for (20) Massalia : Mean anomaly = 208.59684663 deg Arg. of pericenter = 256.75513627 deg Long. of node = 206.19596614 deg Inclination = 0.70819039 deg Eccentricity = 0.14246739 Semimajor axis = 2.40886296 AU Perihelion dist = 2.06567853 AU Mag: H = 6.49, G = 0.25 Epoch of elements : MJD 56213.86300000 TDT (2012 Oct 13.863) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Oct 13 20 Massalia 20h 43.2m UT 11.6 18 58 12.988-22 2 41.05UCAC2 23002514 0.0 11.7 132 6.7 2.659 2.618 3.05 -49.0619 -22.046 -134.29 -8.16 20.7204 0.02887 -0.30706 11.00341 0.92204 0.00572 0.00059 2000 207.57846520121010.00000256.755136206.195966 0.7081900.14246739 2.4088630 2.0656785 6.5 5.00.25 RATE 2.6362460 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.046 0.030 90 1.45 0.031 0 0 0-2 056208.0020121013_002514 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Oct 07, 18:39 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org