IOTA/IOTA-ES occultation update for (591) Irmgard / UCAC2 39607529 event on 2009 Aug 01, 22:33 UT Visible from Summary ------- On 2009 Aug 01 UT, the 52 km diameter asteroid (591) Irmgard will occult a 11.8 mag star in the constellation Aries for observers along a path across . In the case of an occultation, the combined light of the asteroid and the star will drop by 4.7 mag to 16.5 mag (the magnitude of the asteroid) for at most 3.9 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: 34 * date and approx. time of event: 2009 Aug 01, 22:27 - 2009 Aug 01, 22:36 UT * magnitude of target star: 11.8 * magnitude drop [mag]: 4.7 * estimated maximum duration [s]: 3.9 * Moon: 86 % sunlit, 130° distance * Sun: 94° distance * rough path description: The occultation path -------------------- * approximate projected width [km]: 68 * 1 sigma uncertainty interval [path widths]: +/- 1.98 * 1 sigma uncertainty interval [seconds]: +/- 8.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .060 +/- .035) * 1 sigma uncertainty ellipse (major, minor, PA): ( .061", .035", 84° ) * approx speed of asteroid's shadow [km/s]: 13.3466 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC2 39607529 by 591 Irmgard on 2009 Aug 1 Centre Star Star Sun Path Limit1 Path Limit2 Error Limit1 Error Limit2 E. Longitude Latitude U.T. Alt Az Alt o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' " Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude 23 30 6 - 3 38 6 22 27 20 9 67 -76 22 25 26 - 3 54 7 24 27 45 - 3 24 59 ... .. .. .. .. .. 27 36 1 - 2 49 49 27 13 0 - 1 13 58 22 27 29 13 67 -73 26 29 37 - 1 21 7 27 54 16 - 1 7 43 23 6 35 - 2 2 31 30 21 45 - 0 49 44 29 51 21 0 42 56 22 27 38 16 67 -71 29 15 30 0 38 59 30 26 2 0 46 23 26 39 8 0 17 13 32 34 0 0 56 0 31 58 57 2 26 41 22 27 47 19 67 -69 31 27 11 2 24 30 32 29 56 2 28 31 29 12 23 2 11 58 34 26 5 2 32 57 33 47 38 4 2 13 22 27 56 21 68 -66 33 18 29 4 1 11 34 16 13 4 2 59 31 16 34 3 54 19 36 4 20 4 3 48 35 23 11 5 31 59 22 28 5 23 68 -64 34 55 52 5 31 47 35 50 3 5 31 58 33 2 37 5 28 48 37 32 22 5 30 5 36 48 58 6 57 25 22 28 15 25 69 -62 36 22 59 6 57 51 37 14 33 6 56 48 34 36 0 6 57 46 38 52 28 6 52 49 38 7 6 8 19 26 22 28 24 27 69 -61 37 42 9 8 20 23 38 31 42 8 18 20 35 59 53 8 22 34 40 6 11 8 12 38 39 19 4 9 38 42 22 28 33 28 70 -59 38 54 57 9 40 3 39 42 54 9 37 12 37 16 20 9 44 4 41 14 38 9 30 4 40 25 56 10 55 39 22 28 42 30 71 -57 40 2 28 10 57 22 40 49 9 10 53 49 38 26 46 11 2 54 42 18 40 10 45 29 41 28 30 12 10 40 22 28 51 31 71 -56 41 5 33 12 12 40 41 51 12 12 8 32 39 32 12 12 19 30 43 18 55 11 59 9 42 27 21 13 24 0 22 29 0 33 72 -54 42 4 50 13 26 16 42 49 39 13 21 38 40 33 24 13 34 13 44 15 53 13 11 18 43 23 0 14 35 54 22 29 10 34 73 -53 43 0 50 14 38 24 43 44 57 14 33 18 41 30 57 14 47 20 45 9 59 14 22 9 44 15 49 15 46 32 22 29 19 35 74 -51 43 53 57 15 49 15 44 37 30 15 43 45 42 25 20 15 59 3 46 1 32 15 31 51 45 6 8 16 56 4 22 29 28 36 75 -50 44 44 30 16 58 58 45 27 36 16 53 5 43 16 56 17 9 33 46 50 49 16 40 31 45 54 14 18 4 37 22 29 37 37 75 -48 45 32 47 18 7 41 46 15 30 18 1 28 44 6 3 18 18 59 47 38 4 17 48 16 46 40 18 19 12 17 22 29 46 38 76 -47 46 19 0 19 15 31 47 1 26 19 8 59 44 52 56 19 27 29 48 23 29 18 55 13 47 24 33 20 19 11 22 29 55 39 77 -46 47 3 22 20 22 33 47 45 34 20 15 45 45 37 49 20 35 8 49 7 15 20 1 26 48 7 9 21 25 24 22 30 4 40 78 -44 47 46 3 21 28 54 48 28 5 21 21 50 46 20 53 21 42 3 49 49 29 21 7 0 48 48 14 22 31 0 22 30 14 41 80 -43 48 27 12 22 34 38 49 9 7 22 27 18 47 2 17 22 48 19 50 30 21 22 12 0 49 27 56 23 36 3 22 30 23 42 81 -42 49 6 55 23 39 49 49 48 47 23 32 14 47 42 9 23 53 59 51 9 56 23 16 28 50 6 21 24 40 37 22 30 32 43 82 -41 49 45 20 24 44 30 50 27 12 24 36 41 48 20 37 24 59 9 51 48 21 24 20 30 50 43 34 25 44 46 22 30 41 43 83 -39 50 22 33 25 48 44 51 4 27 25 40 43 48 57 47 26 3 51 52 25 41 25 24 6 51 19 42 26 48 31 22 30 50 44 84 -38 50 58 39 26 52 36 51 40 37 26 44 22 49 33 45 27 8 9 53 2 0 26 27 21 51 54 48 27 51 57 22 30 59 45 86 -37 51 33 42 27 56 8 52 15 46 27 47 42 50 8 35 28 12 6 53 37 24 27 30 17 52 28 57 28 55 5 22 31 8 45 87 -36 52 7 46 28 59 23 52 50 0 28 50 44 50 42 21 29 15 45 54 11 56 28 32 57 53 2 13 29 57 59 22 31 18 46 88 -35 52 40 56 30 2 22 53 23 21 29 53 32 51 15 8 30 19 8 54 45 39 29 35 22 53 34 38 31 0 40 22 31 27 46 90 -33 53 13 14 31 5 9 53 55 53 30 56 8 51 46 59 31 22 18 55 18 38 30 37 35 54 6 15 32 3 11 22 31 36 47 91 -32 53 44 43 32 7 46 54 27 38 31 58 33 52 17 57 32 25 17 55 50 54 31 39 39 54 37 8 33 5 35 22 31 45 47 92 -31 54 15 27 33 10 15 54 58 40 33 0 51 52 48 4 33 28 8 56 22 30 32 41 35 55 7 18 34 7 52 22 31 54 48 94 -30 54 45 27 34 12 37 55 29 0 34 3 3 53 17 23 34 30 52 56 53 29 33 43 25 55 36 48 35 10 5 22 32 3 48 95 -29 55 14 46 35 14 56 55 58 41 35 5 10 53 45 56 35 33 32 57 23 54 34 45 12 56 5 40 36 12 16 22 32 13 48 97 -28 55 43 25 36 17 12 56 27 46 36 7 16 54 13 45 36 36 10 57 53 45 35 46 56 56 33 56 37 14 26 22 32 22 49 98 -27 56 11 27 37 19 28 56 56 15 37 9 21 54 40 51 37 38 48 58 23 6 36 48 40 57 1 37 38 16 39 22 32 31 49 100 -26 56 38 53 38 21 46 57 24 10 38 11 28 55 7 16 38 41 27 58 51 58 37 50 25 57 28 44 39 18 55 22 32 40 49 101 -25 57 5 45 39 24 8 57 51 34 39 13 39 55 33 1 39 44 10 59 20 22 38 52 15 57 55 19 40 21 16 22 32 49 49 103 -24 57 32 2 40 26 34 58 18 26 40 15 55 55 58 7 40 46 58 59 48 20 39 54 9 58 21 23 41 23 45 22 32 58 49 105 -23 57 57 47 41 29 9 58 44 49 41 18 18 56 22 34 41 49 54 60 15 55 40 56 10 58 46 57 42 26 23 22 33 7 49 106 -22 58 23 1 42 31 52 59 10 43 42 20 50 56 46 23 42 52 59 60 43 5 41 58 20 59 12 2 43 29 12 22 33 17 49 108 -21 58 47 43 43 34 47 59 36 9 43 23 34 57 9 35 43 56 16 61 9 54 43 0 40 59 36 38 44 32 14 22 33 26 49 109 -20 59 11 55 44 37 54 60 1 9 44 26 30 57 32 9 44 59 46 61 36 23 44 3 13 60 0 45 45 35 30 22 33 35 49 111 -18 59 35 37 45 41 17 60 25 41 45 29 40 57 54 4 46 3 31 62 2 31 45 6 0 60 24 25 46 39 4 22 33 44 49 112 -17 59 58 49 46 44 56 60 49 48 46 33 8 58 15 22 47 7 33 62 28 21 46 9 3 60 47 36 47 42 56 22 33 53 49 114 -16 60 21 30 47 48 55 61 13 28 47 36 54 58 36 0 48 11 56 62 53 52 47 12 25 61 10 19 48 47 10 22 34 2 49 116 -15 60 43 41 48 53 15 61 36 43 48 41 2 58 55 57 49 16 39 63 19 7 48 16 7 61 32 33 49 51 47 22 34 11 48 117 -14 61 5 21 49 57 58 61 59 32 49 45 32 59 15 12 50 21 47 63 44 4 49 20 11 61 54 19 50 56 50 22 34 21 48 119 -13 61 26 28 51 3 7 62 21 54 50 50 28 59 33 43 51 27 22 64 8 46 50 24 40 62 15 34 52 2 21 22 34 30 48 120 -12 61 47 2 52 8 45 62 43 49 51 55 52 59 51 26 52 33 25 64 33 11 51 29 36 62 36 17 53 8 22 22 34 39 48 122 -11 62 7 1 53 14 54 63 5 16 53 1 47 60 8 20 53 40 0 64 57 22 52 35 2 62 56 27 54 14 58 22 34 48 47 123 -10 62 26 23 54 21 36 63 26 13 54 8 15 60 24 20 54 47 10 65 21 16 53 41 0 63 16 1 55 22 9 22 34 57 47 125 -9 62 45 5 55 28 55 63 46 39 55 15 19 60 39 21 55 54 57 65 44 55 54 47 32 63 34 57 56 30 1 22 35 6 46 126 -8 63 3 3 56 36 54 64 6 31 56 23 3 60 53 17 57 3 25 66 8 19 55 54 43 63 53 11 57 38 35 22 35 15 46 127 -7 63 20 13 57 45 37 64 25 47 57 31 29 61 6 0 58 12 37 66 31 25 57 2 36 64 10 38 58 47 56 22 35 25 45 129 -6 63 36 30 58 55 6 64 44 22 58 40 41 61 17 23 59 22 36 66 54 15 58 11 12 64 27 13 59 58 7 22 35 34 44 130 -5 63 51 48 60 5 26 65 2 13 59 50 43 61 27 13 60 33 28 67 16 45 59 20 38 64 42 48 61 9 13 22 35 43 44 131 -4 64 5 56 61 16 41 65 19 11 61 1 40 61 35 16 61 45 15 67 38 54 60 30 56 64 57 14 62 21 19 22 35 52 43 132 -3 64 18 46 62 28 55 65 35 12 62 13 36 61 41 16 62 58 3 68 0 41 61 42 11 65 10 20 63 34 28 22 36 1 42 133 -2 64 30 3 63 42 15 65 50 3 63 26 36 61 44 50 64 11 57 68 22 0 62 54 28 65 21 51 64 48 48 22 36 10 42 134 -1 64 39 31 64 56 45 66 3 33 64 40 45 61 45 30 65 27 2 68 42 47 64 7 52 65 31 27 66 4 25 22 36 20 41 135 0 64 46 46 66 12 32 66 15 26 65 56 11 61 42 41 66 43 25 69 2 57 65 22 30 Uncertainty in time = +/- 10 secs [Prediction of 2008 Mar 20.0] Data for the target star ------------------------ * name: UCAC2 39607529 * constellation : Aries * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 02 00 04.6646 DE: +22 04 48.336 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .054, .030 ) * V mag [mag]: 11.8 * B mag [mag]: 0.0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (591) Irmgard approx. diameter [km]: 52 approx. diameter ["]: .024 distance from Earth [AU]: 2.99600 * orbital information: orbit source: Preston date of fit: 2008 Mar 20 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 688 number of rejected observations: 38 time covered by the observations: 1906 Mar 18 - 2007 Sep 12 1 sigma uncertainty ellipse (major, minor, PA): 0.028, 0.017, 63° remarks: * orbital elements for (591) Irmgard : Mean anomaly = 188.60295338 deg Arg. of pericenter = 217.72749273 deg Long. of node = 334.30741677 deg Inclination = 12.48844580 deg Eccentricity = 0.20663725 Semimajor axis = 2.67919974 AU Perihelion dist = 2.12557727 AU Mag: H = 10.55, G = 0.15 Epoch of elements : MJD 55044.94000000 TDT (2009 Aug 01.940) ------ occelmnt file for Occult BEGIN ----------------------------------- 2009 Aug 1 591 Irmgard 22h 33.3m UT 11.8 2 0 4.665 22 4 48.34UCAC2 39607529 0.0 16.5 52 3.9 2.996 1.052 16.58 101.0369 22.076 -156.74 17.79 22.5546 -0.48601 0.43074 4.98565 5.64731 -0.00525 -0.00203 2000 187.4926962009 728.00000217.727493334.307417 12.4884460.20663725 2.6791997 2.125577310.6 5.00.15 RATE 2.2474830 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.061 0.035 84 2.98 0.047 0 54545.5020090801_607529 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 20, 11:35 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org