IOTA/IOTA-ES occultation update for (1148) Rarahu / HIP 72388 event on 2012 Aug 23, 19:28 UT Visible from Africa Summary ------- On 2012 Aug 23 UT, the 33 km diameter asteroid (1148) Rarahu will occult a 7.8 mag star in the constellation Libra 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 8.1 mag to 15.9 mag (the magnitude of the asteroid) for at most 1.2 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: . The event at a glimpse ---------------------- * Rank: 40 * date and approx. time of event: 2012 Aug 23, 19:30 - 2012 Aug 23, 19:32 UT * geocentric midpoint of event [JD]: 2456163.31172917 * magnitude of target star: 7.8 * magnitude drop [mag]: 8.1 * estimated maximum duration [s]: 1.2 * Moon: 41 % sunlit, 14° distance * Sun: 71° distance * rough path description: Africa Additional comments ------------------- possible double star The occultation path -------------------- * approximate projected width [km]: 34 * 1 sigma uncertainty interval [path widths]: +/- 1.65 * 1 sigma uncertainty interval [seconds]: +/- 2.6 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .031 +/- .024) * 1 sigma uncertainty ellipse (major, minor, PA): ( .031", .023", 94° ) * approx speed of asteroid's shadow [km/s]: 26.5866 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 72388 by 1148 Rarahu on 2012 Aug 23 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 - 22 0 0 - 2 47 55 19 30 5 69 262 0 - 2 57 53 - 2 37 57 - 3 30 44 - 2 5 0 - 21 0 0 - 3 14 7 19 30 9 68 263 -2 - 3 24 3 - 3 4 9 - 3 56 49 - 2 31 17 - 20 0 0 - 3 39 56 19 30 14 67 264 -3 - 3 49 51 - 3 30 0 - 4 22 33 - 2 57 11 - 19 0 0 - 4 5 22 19 30 18 66 265 -4 - 4 15 17 - 3 55 28 - 4 47 54 - 3 22 44 - 18 0 0 - 4 30 26 19 30 22 65 266 -5 - 4 40 19 - 4 20 33 - 5 12 52 - 3 47 53 - 17 0 0 - 4 55 6 19 30 26 64 267 -6 - 5 4 58 - 4 45 14 - 5 37 27 - 4 12 39 - 16 0 0 - 5 19 22 19 30 31 63 268 -7 - 5 29 13 - 5 9 32 - 6 1 37 - 4 37 1 - 15 0 0 - 5 43 14 19 30 35 62 269 -8 - 5 53 3 - 5 33 25 - 6 25 24 - 5 0 58 - 14 0 0 - 6 6 42 19 30 39 61 269 -9 - 6 16 29 - 5 56 54 - 6 48 45 - 5 24 31 - 13 0 0 - 6 29 44 19 30 43 60 270 -10 - 6 39 30 - 6 19 57 - 7 11 42 - 5 47 39 - 12 0 0 - 6 52 20 19 30 47 59 271 -11 - 7 2 5 - 6 42 35 - 7 34 13 - 6 10 21 - 11 0 0 - 7 14 31 19 30 51 58 271 -12 - 7 24 15 - 7 4 48 - 7 56 18 - 6 32 38 - 10 0 0 - 7 36 16 19 30 55 57 271 -13 - 7 45 59 - 7 26 34 - 8 17 57 - 6 54 29 - 9 0 0 - 7 57 35 19 30 58 56 272 -14 - 8 7 16 - 7 47 54 - 8 39 10 - 7 15 53 - 8 0 0 - 8 18 27 19 31 2 55 272 -15 - 8 28 7 - 8 8 47 - 8 59 57 - 7 36 51 - 7 0 0 - 8 38 52 19 31 6 54 272 -16 - 8 48 31 - 8 29 14 - 9 20 17 - 7 57 22 - 6 0 0 - 8 58 51 19 31 9 53 273 -17 - 9 8 28 - 8 49 13 - 9 40 9 - 8 17 25 - 5 0 0 - 9 18 22 19 31 13 52 273 -18 - 9 27 57 - 9 8 45 - 9 59 35 - 8 37 2 - 4 0 0 - 9 37 25 19 31 16 51 273 -20 - 9 47 0 - 9 27 50 -10 18 33 - 8 56 11 - 3 0 0 - 9 56 1 19 31 20 50 273 -21 -10 5 34 - 9 46 27 -10 37 4 - 9 14 52 - 2 0 0 -10 14 9 19 31 23 49 273 -22 -10 23 41 -10 4 37 -10 55 7 - 9 33 5 - 1 0 0 -10 31 49 19 31 27 48 273 -23 -10 41 20 -10 22 18 -11 12 42 - 9 50 51 0 0 0 -10 49 1 19 31 30 47 273 -24 -10 58 31 -10 39 31 -11 29 49 -10 8 8 1 0 0 -11 5 45 19 31 33 46 273 -25 -11 15 14 -10 56 17 -11 46 28 -10 24 57 2 0 0 -11 22 1 19 31 36 45 273 -26 -11 31 29 -11 12 33 -12 2 39 -10 41 17 3 0 0 -11 37 48 19 31 39 44 273 -27 -11 47 15 -11 28 22 -12 18 21 -10 57 10 4 0 0 -11 53 7 19 31 42 43 273 -28 -12 2 33 -11 43 42 -12 33 35 -11 12 33 5 0 0 -12 7 58 19 31 45 42 273 -29 -12 17 22 -11 58 33 -12 48 21 -11 27 28 6 0 0 -12 22 19 19 31 48 41 273 -30 -12 31 43 -12 12 56 -13 2 39 -11 41 54 7 0 0 -12 36 13 19 31 51 40 273 -31 -12 45 35 -12 26 50 -13 16 27 -11 55 52 8 0 0 -12 49 37 19 31 54 39 273 -32 -12 58 58 -12 40 16 -13 29 48 -12 9 20 9 0 0 -13 2 33 19 31 56 38 273 -33 -13 11 53 -12 53 12 -13 42 39 -12 22 20 10 0 0 -13 15 0 19 31 59 37 273 -34 -13 24 19 -13 5 40 -13 55 2 -12 34 51 11 0 0 -13 26 58 19 32 1 36 273 -35 -13 36 16 -13 17 39 -14 6 56 -12 46 53 12 0 0 -13 38 27 19 32 4 35 273 -36 -13 47 44 -13 29 9 -14 18 22 -12 58 26 13 0 0 -13 49 27 19 32 6 34 273 -37 -13 58 44 -13 40 10 -14 29 19 -13 9 30 14 0 0 -13 59 59 19 32 9 33 272 -38 -14 9 15 -13 50 43 -14 39 47 -13 20 5 15 0 0 -14 10 2 19 32 11 32 272 -39 -14 19 17 -14 0 47 -14 49 47 -13 30 11 16 0 0 -14 19 36 19 32 13 31 272 -40 -14 28 50 -14 10 21 -14 59 17 -13 39 49 17 0 0 -14 28 41 19 32 15 30 272 -41 -14 37 55 -14 19 27 -15 8 20 -13 48 57 18 0 0 -14 37 17 19 32 17 29 272 -42 -14 46 30 -14 28 4 -15 16 53 -13 57 36 19 0 0 -14 45 25 19 32 19 28 271 -43 -14 54 37 -14 36 12 -15 24 58 -14 5 46 20 0 0 -14 53 3 19 32 21 27 271 -44 -15 2 15 -14 43 51 -15 32 34 -14 13 27 21 0 0 -15 0 13 19 32 23 26 271 -45 -15 9 25 -14 51 2 -15 39 41 -14 20 40 22 0 0 -15 6 55 19 32 25 25 271 -46 -15 16 5 -14 57 44 -15 46 20 -14 27 23 23 0 0 -15 13 7 19 32 27 24 271 -47 -15 22 17 -15 3 56 -15 52 31 -14 33 38 24 0 0 -15 18 51 19 32 28 23 270 -48 -15 28 0 -15 9 41 -15 58 12 -14 39 23 25 0 0 -15 24 6 19 32 30 22 270 -48 -15 33 15 -15 14 56 -16 3 25 -14 44 40 26 0 0 -15 28 52 19 32 32 21 270 -49 -15 38 1 -15 19 43 -16 8 10 -14 49 28 27 0 0 -15 33 9 19 32 33 20 270 -50 -15 42 18 -15 24 1 -16 12 26 -14 53 47 28 0 0 -15 36 58 19 32 34 19 269 -51 -15 46 7 -15 27 50 -16 16 14 -14 57 37 29 0 0 -15 40 19 19 32 36 18 269 -52 -15 49 27 -15 31 10 -16 19 33 -15 0 59 30 0 0 -15 43 11 19 32 37 17 269 -53 -15 52 18 -15 34 2 -16 22 24 -15 3 52 31 0 0 -15 45 34 19 32 38 16 269 -54 -15 54 41 -15 36 26 -16 24 46 -15 6 16 32 0 0 -15 47 28 19 32 39 15 268 -55 -15 56 36 -15 38 21 -16 26 40 -15 8 11 33 0 0 -15 48 55 19 32 40 14 268 -56 -15 58 2 -15 39 47 -16 28 6 -15 9 38 34 0 0 -15 49 52 19 32 41 14 268 -57 -15 59 0 -15 40 45 -16 29 3 -15 10 36 35 0 0 -15 50 22 19 32 42 13 268 -58 -15 59 29 -15 41 14 -16 29 32 -15 11 5 36 0 0 -15 50 22 19 32 43 12 267 -59 -15 59 30 -15 41 15 -16 29 33 -15 11 6 37 0 0 -15 49 55 19 32 44 11 267 -60 -15 59 2 -15 40 47 -16 29 5 -15 10 39 38 0 0 -15 48 59 19 32 45 10 267 -61 -15 58 6 -15 39 51 -16 28 10 -15 9 42 39 0 0 -15 47 34 19 32 45 9 267 -62 -15 56 42 -15 38 27 -16 26 46 -15 8 18 40 0 0 -15 45 42 19 32 46 8 266 -63 -15 54 49 -15 36 34 -16 24 54 -15 6 24 41 0 0 -15 43 21 19 32 47 7 266 -64 -15 52 28 -15 34 13 -16 22 33 -15 4 3 42 0 0 -15 40 31 19 32 47 6 266 -65 -15 49 39 -15 31 23 -16 19 45 -15 1 12 43 0 0 -15 37 14 19 32 47 5 266 -66 -15 46 22 -15 28 6 -16 16 28 -14 57 54 44 0 0 -15 33 28 19 32 48 4 265 -67 -15 42 36 -15 24 19 -16 12 44 -14 54 7 45 0 0 -15 29 14 19 32 48 3 265 -68 -15 38 23 -15 20 5 -16 8 31 -14 49 52 46 0 0 -15 24 32 19 32 48 2 265 -69 -15 33 41 -15 15 23 -16 3 50 -14 45 8 47 0 0 -15 19 21 19 32 48 1 265 -70 -15 28 31 -15 10 12 -15 58 41 -14 39 56 Uncertainty in time = +/- 3 secs Prediction of 2012 Jul 8.0 Data for the target star ------------------------ * name: HIP 72388 * constellation : Libra * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 14 48 02.2568 DE: -05 30 24.112 * position source: mpos:HIP2 pm:HIP2 plx:HIP2 * standard error: RA,DE ["]: ( .027, .021 ) * V mag [mag]: 7.8 * B mag [mag]: 8.9 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1148) Rarahu approx. diameter [km]: 33 approx. diameter ["]: .015 distance from Earth [AU]: 3.08900 * orbital information: orbit source: Preston date of fit: 2012 Jul 07 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1173 number of rejected observations: 62 time covered by the observations: 1929 Jul 12 - 2012 Jun 21 1 sigma uncertainty ellipse (major, minor, PA): 0.017, 0.011, 105° remarks: * orbital elements for (1148) Rarahu : Mean anomaly = 293.27550169 deg Arg. of pericenter = 174.25022447 deg Long. of node = 145.53872326 deg Inclination = 10.84757053 deg Eccentricity = 0.11260745 Semimajor axis = 3.01632896 AU Perihelion dist = 2.67666785 AU Mag: H = 10.06, G = 0.15 Epoch of elements : MJD 56162.81200000 TDT (2012 Aug 23.812) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Aug 23 1148 Rarahu 19h 28.9m UT 7.8 14 48 2.257- 5 30 24.11HIP 72388 8.9 15.9 33 1.2 3.089 2.560 -19.08 -42.7052 -5.501 -111.61 11.09 19.4815 0.08886 0.17516 13.42548 -6.70401 0.00517 -0.00127 2000 292.7464462012 821.00000174.250224145.538723 10.8475710.11260745 3.0163290 2.676667810.2 5.00.15 RATE 1.8814220 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.031 0.023 94 2.65 0.024 0 0-2-2 056116.0020120823__72388 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 07, 23:48 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org