IOTA/IOTA-ES occultation update for (1633) Chimay / HIP 34856 event on 2012 Sep 17, 00:15 UT Visible from India, Arabia, Africa Summary ------- On 2012 Sep 17 UT, the 36 km diameter asteroid (1633) Chimay will occult a 7.3 mag star in the constellation Gemini for observers along a path across India, Arabia, Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 9.2 mag to 16.5 mag (the magnitude of the asteroid) for at most 1.3 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: 54 * date and approx. time of event: 2012 Sep 17, 00:12 - 2012 Sep 17, 00:14 UT * geocentric midpoint of event [JD]: 2456187.51103333 * magnitude of target star: 7.3 * magnitude drop [mag]: 9.2 * estimated maximum duration [s]: 1.3 * Moon: 1 % sunlit, 80° distance * Sun: 67° distance * rough path description: India, Arabia, Africa Additional comments ------------------- 20" double star The occultation path -------------------- * approximate projected width [km]: 36 * 1 sigma uncertainty interval [path widths]: +/- 1.18 * 1 sigma uncertainty interval [seconds]: +/- 2.7 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .032 +/- .018) * 1 sigma uncertainty ellipse (major, minor, PA): ( .032", .018", 93° ) * approx speed of asteroid's shadow [km/s]: 27.6142 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 34856 by 1633 Chimay on 2012 Sep 17 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 18 0 0 5 15 37 0 12 2 1 69 -66 5 5 8 5 26 6 4 40 23 5 50 50 19 0 0 5 39 1 0 12 3 2 69 -65 5 28 32 5 49 29 5 3 48 6 14 13 20 0 0 6 2 15 0 12 3 3 69 -64 5 51 47 6 12 43 5 27 5 6 37 26 21 0 0 6 25 20 0 12 3 4 69 -63 6 14 53 6 35 48 5 50 11 7 0 29 22 0 0 6 48 15 0 12 3 5 69 -62 6 37 48 6 58 42 6 13 8 7 23 21 23 0 0 7 10 59 0 12 4 6 69 -61 7 0 32 7 21 25 6 35 54 7 46 3 24 0 0 7 33 31 0 12 4 7 69 -60 7 23 5 7 43 57 6 58 28 8 8 34 25 0 0 7 55 52 0 12 5 8 69 -59 7 45 27 8 6 17 7 20 51 8 30 52 26 0 0 8 18 0 0 12 6 9 70 -58 8 7 36 8 28 25 7 43 2 8 52 59 27 0 0 8 39 56 0 12 6 11 70 -57 8 29 32 8 50 20 8 5 0 9 14 52 28 0 0 9 1 39 0 12 7 12 70 -56 8 51 16 9 12 2 8 26 45 9 36 33 29 0 0 9 23 8 0 12 8 13 70 -55 9 12 46 9 33 31 8 48 16 9 57 59 30 0 0 9 44 23 0 12 9 14 70 -54 9 34 1 9 54 45 9 9 34 10 19 12 31 0 0 10 5 24 0 12 10 15 70 -53 9 55 3 10 15 45 9 30 37 10 40 10 32 0 0 10 26 10 0 12 11 16 71 -52 10 15 49 10 36 30 9 51 25 11 0 53 33 0 0 10 46 40 0 12 12 17 71 -51 10 36 21 10 57 0 10 11 58 11 21 21 34 0 0 11 6 55 0 12 14 18 71 -50 10 56 36 11 17 14 10 32 16 11 41 34 35 0 0 11 26 54 0 12 15 19 71 -49 11 16 36 11 37 12 10 52 17 12 1 30 36 0 0 11 46 36 0 12 16 20 71 -47 11 36 19 11 56 53 11 12 3 12 21 10 37 0 0 12 6 2 0 12 18 21 72 -46 11 55 46 12 16 19 11 31 31 12 40 33 38 0 0 12 25 11 0 12 19 22 72 -45 12 14 56 12 35 27 11 50 43 12 59 39 39 0 0 12 44 2 0 12 21 23 72 -44 12 33 48 12 54 17 12 9 37 13 18 28 40 0 0 13 2 36 0 12 23 24 72 -43 12 52 22 13 12 50 12 28 14 13 36 59 41 0 0 13 20 52 0 12 24 25 72 -42 13 10 39 13 31 5 12 46 32 13 55 12 42 0 0 13 38 50 0 12 26 26 73 -41 13 28 37 13 49 2 13 4 33 14 13 6 43 0 0 13 56 29 0 12 28 27 73 -40 13 46 17 14 6 40 13 22 14 14 30 43 44 0 0 14 13 49 0 12 30 28 73 -39 14 3 38 14 23 59 13 39 38 14 48 0 45 0 0 14 30 50 0 12 32 29 73 -38 14 20 41 14 41 0 13 56 42 15 4 58 46 0 0 14 47 32 0 12 34 30 74 -37 14 37 23 14 57 41 14 13 26 15 21 37 47 0 0 15 3 55 0 12 36 31 74 -36 14 53 47 15 14 2 14 29 52 15 37 57 48 0 0 15 19 57 0 12 38 32 74 -35 15 9 50 15 30 4 14 45 57 15 53 57 49 0 0 15 35 40 0 12 40 33 74 -34 15 25 34 15 45 46 15 1 43 16 9 37 50 0 0 15 51 3 0 12 42 34 75 -33 15 40 57 16 1 8 15 17 8 16 24 57 51 0 0 16 6 5 0 12 45 35 75 -32 15 56 0 16 16 9 15 32 13 16 39 56 52 0 0 16 20 47 0 12 47 36 75 -31 16 10 43 16 30 50 15 46 58 16 54 35 53 0 0 16 35 8 0 12 50 37 75 -30 16 25 5 16 45 11 16 1 21 17 8 53 54 0 0 16 49 8 0 12 52 38 76 -29 16 39 6 16 59 10 16 15 24 17 22 51 55 0 0 17 2 47 0 12 55 39 76 -28 16 52 46 17 12 48 16 29 6 17 36 28 56 0 0 17 16 5 0 12 57 40 76 -27 17 6 5 17 26 6 16 42 27 17 49 43 57 0 0 17 29 2 0 13 0 41 77 -26 17 19 2 17 39 2 16 55 26 18 2 37 58 0 0 17 41 37 0 13 2 42 77 -25 17 31 38 17 51 36 17 8 4 18 15 10 59 0 0 17 53 51 0 13 5 43 77 -24 17 43 53 18 3 50 17 20 21 18 27 21 60 0 0 18 5 44 0 13 8 44 77 -23 17 55 46 18 15 41 17 32 15 18 39 11 61 0 0 18 17 14 0 13 11 45 78 -22 18 7 17 18 27 11 17 43 48 18 50 39 62 0 0 18 28 23 0 13 13 46 78 -21 18 18 26 18 38 19 17 54 59 19 1 46 63 0 0 18 39 9 0 13 16 47 78 -20 18 29 14 18 49 5 18 5 48 19 12 30 64 0 0 18 49 34 0 13 19 48 79 -19 18 39 39 18 59 29 18 16 15 19 22 52 65 0 0 18 59 37 0 13 22 49 79 -18 18 49 42 19 9 31 18 26 20 19 32 53 66 0 0 19 9 17 0 13 25 50 79 -17 18 59 23 19 19 10 18 36 2 19 42 31 67 0 0 19 18 35 0 13 28 51 80 -16 19 8 42 19 28 28 18 45 22 19 51 47 68 0 0 19 27 31 0 13 31 52 80 -15 19 17 38 19 37 23 18 54 20 20 0 41 69 0 0 19 36 4 0 13 34 53 80 -15 19 26 12 19 45 56 19 2 55 20 9 12 70 0 0 19 44 15 0 13 37 54 80 -14 19 34 24 19 54 6 19 11 8 20 17 21 71 0 0 19 52 3 0 13 40 55 81 -13 19 42 13 20 1 54 19 18 58 20 25 8 72 0 0 19 59 29 0 13 44 56 81 -12 19 49 39 20 9 19 19 26 26 20 32 32 73 0 0 20 6 32 0 13 47 57 81 -11 19 56 43 20 16 22 19 33 31 20 39 34 74 0 0 20 13 13 0 13 50 58 82 -10 20 3 24 20 23 2 19 40 13 20 46 13 75 0 0 20 19 31 0 13 53 59 82 -9 20 9 42 20 29 20 19 46 32 20 52 29 76 0 0 20 25 26 0 13 57 60 82 -8 20 15 38 20 35 14 19 52 29 20 58 23 77 0 0 20 30 58 0 14 0 61 82 -7 20 21 10 20 40 46 19 58 2 21 3 54 78 0 0 20 36 8 0 14 3 61 83 -6 20 26 20 20 45 56 20 3 13 21 9 2 79 0 0 20 40 55 0 14 7 62 83 -5 20 31 7 20 50 42 20 8 1 21 13 48 80 0 0 20 45 19 0 14 10 63 83 -4 20 35 32 20 55 6 20 12 26 21 18 11 81 0 0 20 49 20 0 14 14 64 84 -3 20 39 33 20 59 7 20 16 28 21 22 11 82 0 0 20 52 58 0 14 17 65 84 -2 20 43 12 21 2 45 20 20 7 21 25 48 83 0 0 20 56 13 0 14 21 66 84 -1 20 46 27 21 6 0 20 23 23 21 29 3 84 0 0 20 59 6 0 14 24 67 84 0 20 49 20 21 8 52 20 26 16 21 31 55 Uncertainty in time = +/- 3 secs Prediction of 2012 Jul 21.0 Data for the target star ------------------------ * name: HIP 34856 * constellation : Gemini * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 07 12 46.2722 DE: +21 21 08.670 * position source: mpos:HIP2 pm:HIP2 plx:HIP2 * standard error: RA,DE ["]: ( .016, .011 ) * V mag [mag]: 7.3 * B mag [mag]: 8.4 * Apparent position with proper motion RA(deg): 108.3839775854 DE(deg): 21.3289798404 * Equation of equinoxes (radians) : 0.000066439983983 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1633) Chimay approx. diameter [km]: 36 approx. diameter ["]: .015 distance from Earth [AU]: 3.38500 * orbital information: orbit source: Preston date of fit: 2012 Jul 21 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1272 number of rejected observations: 71 time covered by the observations: 1917 Jan 22 - 2012 Feb 21 1 sigma uncertainty ellipse (major, minor, PA): 0.028, 0.014, 94° remarks: * orbital elements for (1633) Chimay : Mean anomaly = 285.21382505 deg Arg. of pericenter = 64.56293765 deg Long. of node = 114.09837335 deg Inclination = 2.67523659 deg Eccentricity = 0.12436460 Semimajor axis = 3.19566129 AU Perihelion dist = 2.79823414 AU Mag: H = 10.57, G = 0.15 Epoch of elements : MJD 56187.01100000 TDT (2012 Sep 17.011) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 17 1633 Chimay 0h 15.9m UT 7.3 7 12 46.272 21 21 8.67HIP 34856 8.4 16.5 36 1.3 3.385 2.880 -4.57 107.8771 21.354 174.66 2.17 0.2648 -0.00281 -0.02135 15.48674 -1.75804 -0.00533 0.00063 2000 284.0042222012 910.00000 64.562938114.098373 2.6752370.12436460 3.1956613 2.798234210.5 5.00.15 RATE 1.7252930 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.032 0.018 93 2.18 0.017 0 0 2 0 056129.0020120917__34856 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 22, 03:59 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org