IOTA/IOTA-ES occultation update for (335) Roberta / TYC 6242-00340-1 event on 2012 Sep 27, 22:46 UT Visible from Atlantic Ocean Summary ------- On 2012 Sep 27 UT, the 92 km diameter asteroid (335) Roberta will occult a 12.2 mag star in the constellation Ophiuchus for observers along a path across Atlantic Ocean. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.4 mag to 13.3 mag (the magnitude of the asteroid) for at most 3.4 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: 87 * date and approx. time of event: 2012 Sep 27, 22:46 - 2012 Sep 27, 22:48 UT * geocentric midpoint of event [JD]: 2456198.44884583 * magnitude of target star: 12.2 * magnitude drop [mag]: 1.4 * estimated maximum duration [s]: 3.4 * Moon: 95 % sunlit, 77° distance * Sun: 76° distance * rough path description: Atlantic Ocean The occultation path -------------------- * approximate projected width [km]: 151 * 1 sigma uncertainty interval [path widths]: +/- 0.57 * 1 sigma uncertainty interval [seconds]: +/- 1.6 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .031 +/- .035) * 1 sigma uncertainty ellipse (major, minor, PA): ( .035", .031", 1° ) * approx speed of asteroid's shadow [km/s]: 27.4553 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6242-00340-1 by 335 Roberta on 2012 Sep 27 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 ' " Longitude Longitude Longitude Longitude Latitude Latitude Latitude Latitude - 75 0 0 31 28 46 22 46 34 37 195 0 30 47 43 32 10 29 30 1 40 32 58 53 - 74 0 0 31 22 16 22 46 38 37 196 -1 30 41 16 32 3 55 29 55 17 32 52 15 - 73 0 0 31 16 19 22 46 41 37 197 -2 30 35 22 31 57 55 29 49 26 32 46 11 - 72 0 0 31 10 57 22 46 45 37 199 -3 30 30 2 31 52 30 29 44 9 32 40 42 - 71 0 0 31 6 8 22 46 48 37 200 -4 30 25 16 31 47 38 29 39 25 32 35 47 - 70 0 0 31 1 53 22 46 52 36 201 -5 30 21 3 31 43 21 29 35 15 32 31 27 - 69 0 0 30 58 11 22 46 55 36 202 -5 30 17 24 31 39 38 29 31 37 32 27 42 - 68 0 0 30 55 4 22 46 59 36 203 -6 30 14 18 31 36 29 29 28 34 32 24 31 - 67 0 0 30 52 31 22 47 2 35 204 -7 30 11 47 31 33 55 29 26 4 32 21 55 - 66 0 0 30 50 33 22 47 5 35 205 -8 30 9 49 31 31 55 29 24 7 32 19 54 - 65 0 0 30 49 8 22 47 9 35 206 -9 30 8 25 31 30 29 29 22 44 32 18 27 - 64 0 0 30 48 17 22 47 12 34 207 -10 30 7 35 31 29 38 29 21 55 32 17 35 - 63 0 0 30 48 1 22 47 15 34 208 -11 30 7 19 31 29 21 29 21 39 32 17 18 - 62 0 0 30 48 19 22 47 19 34 209 -11 30 7 36 31 29 39 29 21 56 32 17 36 - 61 0 0 30 49 10 22 47 22 33 210 -12 30 8 28 31 30 31 29 22 48 32 18 29 - 60 0 0 30 50 36 22 47 25 33 211 -13 30 9 53 31 31 58 29 24 12 32 19 56 - 59 0 0 30 52 36 22 47 28 32 212 -14 30 11 52 31 33 58 29 26 10 32 21 58 - 58 0 0 30 55 10 22 47 31 32 213 -15 30 14 25 31 36 34 29 28 42 32 24 34 - 57 0 0 30 58 18 22 47 34 31 214 -16 30 17 32 31 39 43 29 31 47 32 27 45 - 56 0 0 31 2 0 22 47 37 31 215 -17 30 21 12 31 43 26 29 35 25 32 31 31 - 55 0 0 31 6 15 22 47 40 30 216 -18 30 25 25 31 47 44 29 39 37 32 35 51 - 54 0 0 31 11 5 22 47 43 29 217 -18 30 30 12 31 52 36 29 44 21 32 40 45 - 53 0 0 31 16 27 22 47 46 29 218 -19 30 35 33 31 58 1 29 49 39 32 46 14 - 52 0 0 31 22 24 22 47 48 28 219 -20 30 41 26 32 4 0 29 55 30 32 52 16 - 51 0 0 31 28 53 22 47 51 28 220 -21 30 47 53 32 10 33 30 1 53 32 58 53 - 50 0 0 31 35 56 22 47 54 27 220 -22 30 54 53 32 17 39 30 8 49 33 6 4 - 49 0 0 31 43 32 22 47 56 26 221 -23 31 2 25 32 25 19 30 16 18 33 13 48 - 48 0 0 31 51 41 22 47 59 26 222 -23 31 10 30 32 33 32 30 24 19 33 22 6 - 47 0 0 32 0 23 22 48 1 25 223 -24 31 19 8 32 42 18 30 32 52 33 30 57 - 46 0 0 32 9 37 22 48 4 24 224 -25 31 28 18 32 51 37 30 41 57 33 40 21 - 45 0 0 32 19 24 22 48 6 24 224 -26 31 38 0 33 1 28 30 51 34 33 50 18 - 44 0 0 32 29 43 22 48 8 23 225 -26 31 48 14 33 11 52 31 1 43 34 0 49 - 43 0 0 32 40 34 22 48 11 22 226 -27 31 58 59 33 22 49 31 12 23 34 11 51 - 42 0 0 32 51 56 22 48 13 21 227 -28 32 10 17 33 34 17 31 23 34 34 23 26 - 41 0 0 33 3 50 22 48 15 21 227 -29 32 22 5 33 46 17 31 35 17 34 35 34 - 40 0 0 33 16 16 22 48 17 20 228 -29 32 34 25 33 58 48 31 47 30 34 48 13 - 39 0 0 33 29 12 22 48 19 19 229 -30 32 47 15 34 11 51 32 0 13 35 1 23 - 38 0 0 33 42 39 22 48 21 18 229 -31 33 0 36 34 25 25 32 13 27 35 15 5 - 37 0 0 33 56 37 22 48 22 17 230 -32 33 14 26 34 39 29 32 27 11 35 29 18 - 36 0 0 34 11 4 22 48 24 17 231 -32 33 28 47 34 54 4 32 41 24 35 44 1 - 35 0 0 34 26 2 22 48 26 16 231 -33 33 43 37 35 9 9 32 56 7 35 59 15 - 34 0 0 34 41 28 22 48 27 15 232 -34 33 58 57 35 24 44 33 11 18 36 14 59 - 33 0 0 34 57 24 22 48 29 14 233 -34 34 14 45 35 40 47 33 26 58 36 31 12 - 32 0 0 35 13 49 22 48 30 13 233 -35 34 31 2 35 57 20 33 43 7 36 47 55 - 31 0 0 35 30 41 22 48 31 13 234 -36 34 47 47 36 14 21 33 59 43 37 5 6 - 30 0 0 35 48 2 22 48 33 12 235 -36 35 4 59 36 31 51 34 16 46 37 22 46 - 29 0 0 36 5 50 22 48 34 11 235 -37 35 22 39 36 49 48 34 34 17 37 40 54 - 28 0 0 36 24 5 22 48 35 10 236 -37 35 40 45 37 8 12 34 52 14 37 59 29 - 27 0 0 36 42 47 22 48 36 9 237 -38 35 59 18 37 27 3 35 10 38 38 18 32 - 26 0 0 37 1 55 22 48 37 8 237 -38 36 18 17 37 46 20 35 29 27 38 38 0 - 25 0 0 37 21 28 22 48 37 8 238 -39 36 37 41 38 6 3 35 48 41 38 57 55 - 24 0 0 37 41 27 22 48 38 7 238 -39 36 57 30 38 26 11 36 8 20 39 18 15 - 23 0 0 38 1 49 22 48 39 6 239 -40 37 17 43 38 46 44 36 28 23 39 39 1 - 22 0 0 38 22 36 22 48 39 5 240 -40 37 38 20 39 7 41 36 48 49 40 0 10 - 21 0 0 38 43 46 22 48 40 4 240 -41 37 59 21 39 29 2 37 9 39 40 21 43 - 20 0 0 39 5 19 22 48 40 3 241 -41 38 20 44 39 50 45 .. .. .. 40 43 40 - 19 0 0 39 27 14 22 48 40 2 242 -41 38 42 29 40 12 51 .. .. .. 41 5 59 - 18 0 0 39 49 31 22 48 41 2 242 -42 39 4 35 40 35 19 .. .. .. 41 28 39 - 17 0 0 40 12 8 22 48 41 1 243 -42 39 27 2 40 58 7 .. .. .. .. .. .. Uncertainty in time = +/- 2 secs Prediction of 2012 Aug 7.0 Data for the target star ------------------------ * name: TYC 6242-00340-1 * constellation : Ophiuchus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 17 23 46.4051 DE: -19 58 27.776 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .029, .034 ) * V mag [mag]: 12.2 * B mag [mag]: 12.5 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (335) Roberta approx. diameter [km]: 92 approx. diameter ["]: .062 distance from Earth [AU]: 2.03200 * orbital information: orbit source: Preston date of fit: 2012 Aug 06 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): 0.013, 0.009, 98° remarks: * orbital elements for (335) Roberta : Mean anomaly = 1.41582786 deg Arg. of pericenter = 139.31337280 deg Long. of node = 148.50732555 deg Inclination = 5.09436141 deg Eccentricity = 0.17368381 Semimajor axis = 2.47473549 AU Perihelion dist = 2.04491400 AU Mag: H = 9.02, G = 0.15 Epoch of elements : MJD 56197.94900000 TDT (2012 Sep 27.949) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 27 335 Roberta 22h 46.3m UT 12.2 17 23 46.405-19 58 27.78TYC 6242-00340-1 12.5 13.3 92 3.4 2.032 4.698 -10.44 -87.7659 -19.971 -163.91 -2.08 22.7723 0.12673 0.78204 15.30709 -2.41557 0.00511 -0.00025 2000 359.4033862012 920.00000139.313373148.507326 5.0943610.17368381 2.4747355 2.0449140 9.0 5.00.15 RATE 2.5316920 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.035 0.031 1 1.57 0.035 0 0 1 4 056146.0020120927_0340-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Aug 06, 21:10 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org