IOTA/IOTA-ES occultation update for (335) Roberta / HIP 83788 event on 2012 Sep 18, 23:27 UT Visible from Argentina, Chile Summary ------- On 2012 Sep 18 UT, the 93 km diameter asteroid (335) Roberta will occult a 7.6 mag star in the constellation Ophiuchus for observers along a path across Argentina, Chile. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.6 mag to 13.2 mag (the magnitude of the asteroid) for at most 3.8 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: . The event at a glimpse ---------------------- * Rank: 99 * date and approx. time of event: 2012 Sep 18, 23:28 - 2012 Sep 18, 23:32 UT * geocentric midpoint of event [JD]: 2456189.47765833 * magnitude of target star: 7.6 * magnitude drop [mag]: 5.6 * estimated maximum duration [s]: 3.8 * Moon: 11 % sunlit, 43° distance * Sun: 81° distance * rough path description: Argentina, Chile The occultation path -------------------- * approximate projected width [km]: 97 * 1 sigma uncertainty interval [path widths]: +/- 0.24 * 1 sigma uncertainty interval [seconds]: +/- 1.5 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .028 +/- .016) * 1 sigma uncertainty ellipse (major, minor, PA): ( .028", .016", 92° ) * approx speed of asteroid's shadow [km/s]: 24.7724 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 83788 by 335 Roberta on 2012 Sep 18 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 - 84 0 0 -34 32 23 23 28 37 73 329 -1 -34 58 51 -34 5 58 -35 11 34 -33 53 18 - 83 0 0 -34 39 35 23 28 40 72 326 -1 -35 6 1 -34 13 11 -35 18 43 -34 0 32 - 82 0 0 -34 46 26 23 28 44 71 324 -2 -35 12 50 -34 20 4 -35 25 32 -34 7 26 - 81 0 0 -34 52 56 23 28 48 71 321 -3 -35 19 19 -34 26 36 -35 32 0 -34 13 58 - 80 0 0 -34 59 6 23 28 51 70 319 -4 -35 25 28 -34 32 47 -35 38 8 -34 20 10 - 79 0 0 -35 4 55 23 28 55 70 317 -5 -35 31 16 -34 38 37 -35 43 55 -34 26 1 - 78 0 0 -35 10 23 23 28 59 69 315 -6 -35 36 43 -34 44 7 -35 49 22 -34 31 31 - 77 0 0 -35 15 31 23 29 2 68 313 -6 -35 41 49 -34 49 16 -35 54 28 -34 36 40 - 76 0 0 -35 20 18 23 29 6 68 311 -7 -35 46 35 -34 54 4 -35 59 13 -34 41 29 - 75 0 0 -35 24 45 23 29 9 67 309 -8 -35 51 1 -34 58 31 -36 3 38 -34 45 57 - 74 0 0 -35 28 50 23 29 13 66 308 -9 -35 55 6 -35 2 38 -36 7 43 -34 50 4 - 73 0 0 -35 32 36 23 29 16 66 306 -10 -35 58 50 -35 6 24 -36 11 27 -34 53 50 - 72 0 0 -35 36 0 23 29 20 65 305 -10 -36 2 14 -35 9 49 -36 14 50 -34 57 16 - 71 0 0 -35 39 4 23 29 23 64 303 -11 -36 5 17 -35 12 54 -36 17 53 -35 0 21 - 70 0 0 -35 41 48 23 29 27 64 302 -12 -36 8 0 -35 15 38 -36 20 36 -35 3 6 - 69 0 0 -35 44 11 23 29 30 63 300 -13 -36 10 22 -35 18 2 -36 22 58 -35 5 29 - 68 0 0 -35 46 13 23 29 34 62 299 -14 -36 12 24 -35 20 4 -36 25 0 -35 7 32 - 67 0 0 -35 47 55 23 29 37 61 298 -15 -36 14 6 -35 21 47 -36 26 41 -35 9 15 - 66 0 0 -35 49 16 23 29 40 61 296 -15 -36 15 27 -35 23 8 -36 28 2 -35 10 37 - 65 0 0 -35 50 17 23 29 44 60 295 -16 -36 16 27 -35 24 9 -36 29 2 -35 11 38 - 64 0 0 -35 50 57 23 29 47 59 294 -17 -36 17 8 -35 24 50 -36 29 42 -35 12 18 - 63 0 0 -35 51 17 23 29 50 58 293 -18 -36 17 28 -35 25 10 -36 30 2 -35 12 38 - 62 0 0 -35 51 17 23 29 53 58 292 -19 -36 17 27 -35 25 9 -36 30 2 -35 12 38 - 61 0 0 -35 50 56 23 29 57 57 291 -19 -36 17 6 -35 24 48 -36 29 41 -35 12 16 - 60 0 0 -35 50 14 23 30 0 56 290 -20 -36 16 25 -35 24 6 -36 28 59 -35 11 35 - 59 0 0 -35 49 12 23 30 3 55 289 -21 -36 15 23 -35 23 4 -36 27 58 -35 10 32 - 58 0 0 -35 47 49 23 30 6 55 288 -22 -36 14 1 -35 21 41 -36 26 36 -35 9 9 - 57 0 0 -35 46 7 23 30 9 54 287 -23 -36 12 18 -35 19 58 -36 24 54 -35 7 26 - 56 0 0 -35 44 3 23 30 12 53 286 -23 -36 10 15 -35 17 54 -36 22 51 -35 5 22 - 55 0 0 -35 41 39 23 30 15 52 285 -24 -36 7 52 -35 15 29 -36 20 28 -35 2 57 - 54 0 0 -35 38 55 23 30 18 51 284 -25 -36 5 8 -35 12 45 -36 17 45 -35 0 12 - 53 0 0 -35 35 50 23 30 21 51 283 -26 -36 2 4 -35 9 39 -36 14 41 -34 57 6 - 52 0 0 -35 32 25 23 30 24 50 282 -27 -35 58 40 -35 6 13 -36 11 17 -34 53 40 - 51 0 0 -35 28 40 23 30 27 49 281 -27 -35 54 55 -35 2 27 -36 7 33 -34 49 53 - 50 0 0 -35 24 34 23 30 30 48 281 -28 -35 50 50 -34 58 20 -36 3 28 -34 45 45 - 49 0 0 -35 20 7 23 30 33 47 280 -29 -35 46 25 -34 53 52 -35 59 3 -34 41 17 - 48 0 0 -35 15 20 23 30 35 47 279 -30 -35 41 39 -34 49 4 -35 54 18 -34 36 29 - 47 0 0 -35 10 13 23 30 38 46 278 -31 -35 36 33 -34 43 56 -35 49 12 -34 31 20 - 46 0 0 -35 4 45 23 30 41 45 277 -31 -35 31 6 -34 38 27 -35 43 46 -34 25 50 - 45 0 0 -34 58 57 23 30 44 44 277 -32 -35 25 19 -34 32 37 -35 38 0 -34 20 0 - 44 0 0 -34 52 48 23 30 46 43 276 -33 -35 19 12 -34 26 27 -35 31 53 -34 13 49 - 43 0 0 -34 46 19 23 30 49 43 275 -34 -35 12 44 -34 19 56 -35 25 26 -34 7 18 - 42 0 0 -34 39 29 23 30 52 42 274 -35 -35 5 56 -34 13 5 -35 18 39 -34 0 26 - 41 0 0 -34 32 19 23 30 54 41 274 -35 -34 58 48 -34 5 54 -35 11 31 -33 53 14 - 40 0 0 -34 24 49 23 30 57 40 273 -36 -34 51 19 -33 58 22 -35 4 3 -33 45 41 - 39 0 0 -34 16 58 23 30 59 39 272 -37 -34 43 30 -33 50 29 -34 56 15 -33 37 48 - 38 0 0 -34 8 47 23 31 2 38 272 -38 -34 35 20 -33 42 16 -34 48 6 -33 29 34 - 37 0 0 -34 0 15 23 31 4 38 271 -39 -34 26 50 -33 33 43 -34 39 37 -33 21 0 - 36 0 0 -33 51 23 23 31 6 37 270 -39 -34 18 0 -33 24 49 -34 30 48 -33 12 5 - 35 0 0 -33 42 11 23 31 9 36 269 -40 -34 8 50 -33 15 35 -34 21 38 -33 2 50 - 34 0 0 -33 32 38 23 31 11 35 269 -41 -33 59 19 -33 6 0 -34 12 8 -32 53 14 - 33 0 0 -33 22 45 23 31 13 34 268 -42 -33 49 28 -32 56 5 -34 2 18 -32 43 18 - 32 0 0 -33 12 32 23 31 16 33 268 -43 -33 39 17 -32 45 50 -33 52 8 -32 33 2 - 31 0 0 -33 1 58 23 31 18 33 267 -43 -33 28 45 -32 35 14 -33 41 38 -32 22 25 - 30 0 0 -32 51 4 23 31 20 32 266 -44 -33 17 53 -32 24 18 -33 30 47 -32 11 28 - 29 0 0 -32 39 50 23 31 22 31 266 -45 -33 6 42 -32 13 2 -33 19 36 -32 0 11 - 28 0 0 -32 28 16 23 31 24 30 265 -46 -32 55 10 -32 1 25 -33 8 5 -31 48 33 - 27 0 0 -32 16 22 23 31 26 29 264 -47 -32 43 18 -31 49 29 -32 56 14 -31 36 36 - 26 0 0 -32 4 8 23 31 28 28 264 -47 -32 31 6 -31 37 12 -32 44 3 -31 24 18 - 25 0 0 -31 51 33 23 31 30 27 263 -48 -32 18 34 -31 24 36 -32 31 33 -31 11 41 - 24 0 0 -31 38 39 23 31 32 26 263 -49 -32 5 42 -31 11 39 -32 18 42 -30 58 43 - 23 0 0 -31 25 25 23 31 34 26 262 -50 -31 52 30 -30 58 23 -32 5 32 -30 45 25 - 22 0 0 -31 11 51 23 31 35 25 262 -50 -31 38 59 -30 44 47 -31 52 1 -30 31 48 - 21 0 0 -30 57 58 23 31 37 24 261 -51 -31 25 8 -30 30 51 -31 38 11 -30 17 51 - 20 0 0 -30 43 45 23 31 39 23 260 -52 -31 10 57 -30 16 36 -31 24 2 -30 3 35 - 19 0 0 -30 29 12 23 31 40 22 260 -53 -30 56 27 -30 2 1 -31 9 33 -29 48 59 - 18 0 0 -30 14 21 23 31 42 21 259 -54 -30 41 38 -29 47 6 -30 54 45 -29 34 3 - 17 0 0 -29 59 10 23 31 43 20 259 -54 -30 26 29 -29 31 53 -30 39 38 -29 18 48 - 16 0 0 -29 43 39 23 31 45 19 258 -55 -30 11 2 -29 16 20 -30 24 11 -29 3 15 - 15 0 0 -29 27 50 23 31 46 18 258 -56 -29 55 15 -29 0 29 -30 8 26 -28 47 22 - 14 0 0 -29 11 42 23 31 47 18 257 -57 -29 39 9 -28 44 18 -29 52 21 -28 31 10 - 13 0 0 -28 55 15 23 31 49 17 257 -57 -29 22 45 -28 27 49 -29 35 58 -28 14 40 - 12 0 0 -28 38 30 23 31 50 16 256 -58 -29 6 2 -28 11 1 -29 19 17 -27 57 51 - 11 0 0 -28 21 27 23 31 51 15 256 -59 -28 49 1 -27 53 55 -29 2 17 -27 40 44 - 10 0 0 -28 4 5 23 31 52 14 255 -60 -28 31 42 -27 36 31 -28 44 59 -27 23 19 - 9 0 0 -27 46 25 23 31 53 13 255 -60 -28 14 5 -27 18 49 -28 27 23 -27 5 35 - 8 0 0 -27 28 28 23 31 54 12 254 -61 -27 56 10 -27 0 49 -28 9 29 -26 47 35 - 7 0 0 -27 10 13 23 31 55 11 254 -62 -27 37 57 -26 42 32 -27 51 17 -26 29 16 - 6 0 0 -26 51 41 23 31 56 10 253 -62 -27 19 28 -26 23 58 -27 32 49 -26 10 41 - 5 0 0 -26 32 52 23 31 56 9 253 -63 -27 0 41 -26 5 6 -27 14 3 -25 51 48 - 4 0 0 -26 13 46 23 31 57 8 252 -64 -26 41 37 -25 45 58 -26 55 0 -25 32 39 - 3 0 0 -25 54 23 23 31 58 7 252 -64 -26 22 17 -25 26 33 -26 35 41 -25 13 13 - 2 0 0 -25 34 45 23 31 58 6 252 -65 -26 2 40 -25 6 53 -26 16 6 -24 53 31 - 1 0 0 -25 14 50 23 31 59 5 251 -65 -25 42 48 -24 46 56 -25 56 14 -24 33 33 0 0 0 -24 54 40 23 31 59 4 251 -66 -25 22 40 -24 26 44 -25 36 7 -24 13 20 1 0 0 -24 34 14 23 31 59 3 250 -67 -25 2 16 -24 6 16 -25 15 45 -23 52 52 2 0 0 -24 13 34 23 32 0 2 250 -67 -24 41 38 -23 45 34 -24 55 8 -23 32 8 3 0 0 -23 52 39 23 32 0 1 249 -67 -24 20 45 -23 24 37 -24 34 15 -23 11 10 4 0 0 -23 31 30 23 32 0 0 249 -68 -23 59 37 -23 3 25 -24 13 9 -22 49 58 Uncertainty in time = +/- 2 secs Prediction of 2012 Jul 21.0 Data for the target star ------------------------ * name: HIP 83788 * constellation : Ophiuchus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 17 07 27.0191 DE: -19 17 13.725 * position source: mpos:HIP2 pm:HIP2 plx:HIP2 * standard error: RA,DE ["]: ( .025, .013 ) * V mag [mag]: 7.6 * B mag [mag]: 9.0 * Apparent position with proper motion RA(deg): 257.0530832297 DE(deg): -19.3019459466 * Equation of equinoxes (radians) : 0.000065494247557 * Diameter [mas]: 1 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (335) Roberta approx. diameter [km]: 93 approx. diameter ["]: .066 distance from Earth [AU]: 1.93800 * orbital information: orbit source: Preston date of fit: 2012 Jul 21 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1305 number of rejected observations: 145 time covered by the observations: 1903 May 06 - 2012 Jul 19 1 sigma uncertainty ellipse (major, minor, PA): 0.014, 0.009, 99° remarks: * orbital elements for (335) Roberta : Mean anomaly = 359.14413165 deg Arg. of pericenter = 139.31395761 deg Long. of node = 148.50750390 deg Inclination = 5.09434272 deg Eccentricity = 0.17369317 Semimajor axis = 2.47476355 AU Perihelion dist = 2.04491403 AU Mag: H = 9.02, G = 0.15 Epoch of elements : MJD 56188.97800000 TDT (2012 Sep 18.978) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 18 335 Roberta 23h 27.8m UT 7.6 17 7 27.019-19 17 13.73HIP 83788 9.1 13.2 94 3.8 1.938 4.393 -12.43 -93.3758 -19.284 -173.50 1.41 23.4638 -0.04445 -0.22741 13.71092 -2.74094 0.00521 -0.00042 2000 356.8712172012 910.00000139.313958148.507504 5.0943430.17369317 2.4747636 2.0449140 9.0 5.00.15 RATE 2.5316500 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.028 0.016 92 1.24 0.016 0 1 1 5 056129.0020120918__83788 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 22, 04:06 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org