IOTA/IOTA-ES occultation update for (1555) Dejan / HIP 26650 event on 2012 Oct 06, 08:34 UT Visible from Bolivia, Argentina, Chile Summary ------- On 2012 Oct 06 UT, the 24 km diameter asteroid (1555) Dejan will occult a 8.5 mag star in the constellation Auriga for observers along a path across Bolivia, Argentina, Chile. In the case of an occultation, the combined light of the asteroid and the star will drop by 7.0 mag to 15.5 mag (the magnitude of the asteroid) for at most 2.8 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: 59 * date and approx. time of event: 2012 Oct 06, 08:26 - 2012 Oct 06, 08:35 UT * geocentric midpoint of event [JD]: 2456206.85724583 * magnitude of target star: 8.5 * magnitude drop [mag]: 7.0 * estimated maximum duration [s]: 2.8 * Moon: 69 % sunlit, 10° distance * Sun: 107° distance * rough path description: Bolivia, Argentina, Chile The occultation path -------------------- * approximate projected width [km]: 36 * 1 sigma uncertainty interval [path widths]: +/- 1.06 * 1 sigma uncertainty interval [seconds]: +/- 4.1 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .036 +/- .021) * 1 sigma uncertainty ellipse (major, minor, PA): ( .036", .021", 92° ) * approx speed of asteroid's shadow [km/s]: 8.5592 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 26650 by 1555 Dejan on 2012 Oct 6 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 - 99 54 21 -49 0 0 8 26 8 1 36 -30 - 99 36 23 -100 12 18 - 98 58 12 ... .. .. - 98 46 0 -48 0 0 8 26 8 2 35 -30 - 98 28 17 - 99 3 42 - 97 50 36 - 99 41 6 - 97 37 47 -47 0 0 8 26 10 4 34 -31 - 97 20 17 - 97 55 16 - 96 43 4 - 98 32 11 - 96 29 36 -46 0 0 8 26 11 5 33 -31 - 96 12 18 - 96 46 53 - 95 35 30 - 97 23 23 - 95 21 22 -45 0 0 8 26 14 6 32 -31 - 95 4 15 - 95 38 28 - 94 27 49 - 96 14 35 - 94 12 59 -44 0 0 8 26 17 8 32 -31 - 93 56 1 - 94 29 55 - 93 19 55 - 95 5 42 - 93 4 22 -43 0 0 8 26 20 9 31 -32 - 92 47 32 - 93 21 10 - 92 11 43 - 93 56 40 - 91 55 26 -42 0 0 8 26 24 10 30 -32 - 91 38 43 - 92 12 7 - 91 3 8 - 92 47 21 - 90 46 4 -41 0 0 8 26 29 11 29 -32 - 90 29 27 - 91 2 39 - 89 54 4 - 91 37 41 - 89 36 12 -40 0 0 8 26 34 13 28 -32 - 89 19 39 - 89 52 43 - 88 44 25 - 90 27 34 - 88 25 44 -39 0 0 8 26 40 14 27 -32 - 88 9 14 - 88 42 11 - 87 34 6 - 89 16 54 - 87 14 32 -38 0 0 8 26 47 15 27 -32 - 86 58 5 - 87 30 57 - 86 23 1 - 88 5 36 - 86 2 32 -37 0 0 8 26 55 17 26 -31 - 85 46 5 - 86 18 56 - 85 11 2 - 86 53 32 - 84 49 36 -36 0 0 8 27 3 18 25 -31 - 84 33 8 - 85 6 0 - 83 58 4 - 85 40 37 - 83 35 36 -35 0 0 8 27 12 19 24 -31 - 83 19 7 - 83 52 2 - 82 43 58 - 84 26 42 - 82 20 26 -34 0 0 8 27 21 21 23 -30 - 82 3 53 - 82 36 55 - 81 28 35 - 83 11 41 - 81 3 55 -33 0 0 8 27 32 22 22 -30 - 80 47 17 - 81 20 29 - 80 11 48 - 81 55 25 - 79 45 55 -32 0 0 8 27 43 23 21 -30 - 79 29 10 - 80 2 36 - 78 53 26 - 80 37 45 - 78 26 16 -31 0 0 8 27 55 25 20 -29 - 78 9 22 - 78 43 5 - 77 33 18 - 79 18 31 - 77 4 44 -30 0 0 8 28 8 26 19 -28 - 76 47 40 - 77 21 44 - 76 11 12 - 77 57 31 - 75 41 8 -29 0 0 8 28 22 27 18 -28 - 75 23 50 - 75 58 20 - 74 46 53 - 76 34 33 - 74 15 10 -28 0 0 8 28 37 29 16 -27 - 73 57 37 - 74 32 39 - 73 20 4 - 75 9 23 - 72 46 35 -27 0 0 8 28 53 30 15 -26 - 72 28 42 - 73 4 22 - 71 50 28 - 73 41 44 - 71 15 0 -26 0 0 8 29 10 31 14 -25 - 70 56 45 - 71 33 9 - 70 17 40 - 72 11 16 - 69 40 1 -25 0 0 8 29 29 33 12 -24 - 69 21 18 - 69 58 36 - 68 41 13 - 70 37 36 - 68 1 8 -24 0 0 8 29 48 34 11 -23 - 67 41 53 - 68 20 14 - 67 0 36 - 69 0 18 - 66 17 44 -23 0 0 8 30 10 35 9 -21 - 65 57 50 - 66 37 28 - 65 15 6 - 67 18 48 - 64 29 3 -22 0 0 8 30 32 37 7 -20 - 64 8 21 - 64 49 32 - 63 23 52 - 65 32 25 - 62 34 4 -21 0 0 8 30 57 38 5 -18 - 62 12 25 - 62 55 31 - 61 25 45 - 63 40 16 - 60 31 30 -20 0 0 8 31 24 39 3 -16 - 60 8 38 - 60 54 7 - 59 19 13 - 61 41 12 Latitude Latitude Latitude Latitude - 60 0 0 -19 45 14 8 31 31 39 2 -16 -19 55 58 -19 34 33 -20 18 51 -19 12 1 - 59 0 0 -19 17 53 8 31 45 40 1 -15 -19 28 33 -19 7 16 -19 51 16 -18 44 54 - 58 0 0 -18 51 32 8 31 58 40 360 -14 -19 2 7 -18 40 59 -19 24 42 -18 18 45 - 57 0 0 -18 26 10 8 32 12 40 359 -13 -18 36 41 -18 15 41 -18 59 7 -17 53 35 - 56 0 0 -18 1 48 8 32 25 41 357 -12 -18 12 15 -17 51 23 -18 34 33 -17 29 25 - 55 0 0 -17 38 26 8 32 39 41 356 -11 -17 48 49 -17 28 4 -18 10 59 -17 6 13 - 54 0 0 -17 16 3 8 32 52 41 355 -11 -17 26 23 -17 5 45 -17 48 25 -16 44 1 - 53 0 0 -16 54 40 8 33 6 42 354 -10 -17 4 57 -16 44 25 -17 26 52 -16 22 49 - 52 0 0 -16 34 16 8 33 20 42 352 -9 -16 44 30 -16 24 5 -17 6 18 -16 2 35 - 51 0 0 -16 14 53 8 33 34 42 351 -8 -16 25 4 -16 4 44 -16 46 45 -15 43 21 - 50 0 0 -15 56 29 8 33 47 42 350 -7 -16 6 37 -15 46 23 -16 28 12 -15 25 5 - 49 0 0 -15 39 4 8 34 1 42 349 -6 -15 49 9 -15 29 1 -16 10 39 -15 7 49 - 48 0 0 -15 22 39 8 34 15 42 347 -5 -15 32 41 -15 12 38 -15 54 5 -14 51 31 - 47 0 0 -15 7 13 8 34 28 42 346 -4 -15 17 13 -14 57 15 -15 38 32 -14 36 13 - 46 0 0 -14 52 46 8 34 42 42 345 -3 -15 2 44 -14 42 50 -15 23 58 -14 21 53 - 45 0 0 -14 39 18 8 34 56 42 344 -2 -14 49 14 -14 29 24 -15 10 23 -14 8 32 - 44 0 0 -14 26 49 8 35 9 42 343 -1 -14 36 43 -14 16 57 -14 57 48 -13 56 9 Uncertainty in time = +/- 5 secs Prediction of 2012 Jul 10.0 Data for the target star ------------------------ * name: HIP 26650 * constellation : Auriga * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 05 39 50.5514 DE: +31 13 25.872 * position source: mpos:HIP2 pm:HIP2 plx:HIP2 * standard error: RA,DE ["]: ( .024, .013 ) * V mag [mag]: 8.5 * B mag [mag]: 9.0 * Apparent position with proper motion RA(deg): 85.1738024237 DE(deg): 31.2282103241 * Equation of equinoxes (radians) : 0.000062252170787 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1555) Dejan approx. diameter [km]: 24 approx. diameter ["]: .021 distance from Earth [AU]: 1.60300 * orbital information: orbit source: Preston date of fit: 2012 Jul 09 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1071 number of rejected observations: 27 time covered by the observations: 1932 Aug 01 - 2011 Jul 27 1 sigma uncertainty ellipse (major, minor, PA): 0.026, 0.016, 94° remarks: * orbital elements for (1555) Dejan : Mean anomaly = 30.44742210 deg Arg. of pericenter = 48.18358816 deg Long. of node = 318.13375128 deg Inclination = 6.01428008 deg Eccentricity = 0.27617707 Semimajor axis = 2.69107967 AU Perihelion dist = 1.94786519 AU Mag: H = 11.57, G = 0.15 Epoch of elements : MJD 56206.35800000 TDT (2012 Oct 06.358) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Oct 6 1555 Dejan 8h 34.4m UT 8.5 5 39 50.551 31 13 25.87HIP 26650 9.0 15.5 24 2.8 1.603 1.990 7.07 -59.0588 31.221 48.40 -5.33 8.5739 0.19525 -0.71241 4.65583 1.28920 -0.00514 -0.00040 2000 29.0279242012 930.00000 48.183588318.133751 6.0142800.27617707 2.6910797 1.947865211.6 5.00.15 RATE 2.2326170 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.036 0.021 92 2.06 0.022 0 0 4 2 056118.0020121006__26650 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Aug 26, 01:00 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org