IOTA/IOTA-ES occultation update for (113) Amalthea / HIP 39644 event on 2009 Sep 08, 22:42 UT Visible from Summary ------- On 2009 Sep 08 UT, the 46 km diameter asteroid (113) Amalthea will occult a 8.8 mag star in the constellation Cancer for observers along a path across . In the case of an occultation, the combined light of the asteroid and the star will drop by 4.9 mag to 13.7 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: 73 * date and approx. time of event: 2009 Sep 08, 22:39 - 2009 Sep 08, 22:40 UT * magnitude of target star: 8.8 * magnitude drop [mag]: 4.9 * estimated maximum duration [s]: 1.2 * Moon: 81 % sunlit, 83° distance * Sun: 47° distance * rough path description: The occultation path -------------------- * approximate projected width [km]: 49 * 1 sigma uncertainty interval [path widths]: +/- 0.79 * 1 sigma uncertainty interval [seconds]: +/- 1.2 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .023 +/- .016) * 1 sigma uncertainty ellipse (major, minor, PA): ( .023", .016", 91° ) * approx speed of asteroid's shadow [km/s]: 38.6357 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 39644 by 113 Amalthea on 2009 Sep 8 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 54 0 0 28 41 58 22 39 27 1 69 -43 28 27 45 28 56 12 28 5 20 29 18 44 55 0 0 29 2 28 22 39 28 2 70 -42 28 48 16 29 16 41 28 25 52 29 39 12 56 0 0 29 22 44 22 39 28 3 70 -41 29 8 33 29 36 57 28 46 11 29 59 26 57 0 0 29 42 47 22 39 28 4 70 -40 29 28 37 29 56 59 29 6 16 30 19 27 58 0 0 30 2 36 22 39 28 5 71 -39 29 48 27 30 16 47 29 26 8 30 39 14 59 0 0 30 22 11 22 39 28 5 71 -38 30 8 3 30 36 21 29 45 46 30 58 46 60 0 0 30 41 32 22 39 29 6 72 -37 30 27 25 30 55 41 30 5 9 31 18 4 61 0 0 31 0 38 22 39 29 7 73 -36 30 46 32 31 14 45 30 24 17 31 37 7 62 0 0 31 19 29 22 39 29 8 73 -35 31 5 24 31 33 35 30 43 11 31 55 55 63 0 0 31 38 4 22 39 30 9 74 -35 31 24 0 31 52 10 31 1 49 32 14 28 64 0 0 31 56 24 22 39 30 10 74 -34 31 42 21 32 10 29 31 20 12 32 32 45 65 0 0 32 14 29 22 39 31 11 75 -33 32 0 27 32 28 32 31 38 19 32 50 47 66 0 0 32 32 17 22 39 31 12 75 -32 32 18 16 32 46 19 31 56 10 33 8 32 67 0 0 32 49 49 22 39 32 13 76 -31 32 35 49 33 3 50 32 13 45 33 26 1 68 0 0 33 7 4 22 39 32 14 76 -30 32 53 6 33 21 4 32 31 4 33 43 13 69 0 0 33 24 3 22 39 33 14 77 -29 33 10 6 33 38 2 32 48 6 34 0 9 70 0 0 33 40 45 22 39 34 15 77 -28 33 26 49 33 54 43 33 4 51 34 16 48 71 0 0 33 57 10 22 39 34 16 78 -28 33 43 15 34 11 7 33 21 19 34 33 10 72 0 0 34 13 18 22 39 35 17 79 -27 33 59 25 34 27 13 33 37 30 34 49 15 73 0 0 34 29 9 22 39 36 18 79 -26 34 15 16 34 43 3 33 53 23 35 5 3 74 0 0 34 44 42 22 39 37 19 80 -25 34 30 51 34 58 35 34 9 0 35 20 33 75 0 0 34 59 58 22 39 38 20 80 -24 34 46 7 35 13 49 34 24 18 35 35 45 76 0 0 35 14 55 22 39 39 20 81 -23 35 1 7 35 28 46 34 39 19 35 50 40 77 0 0 35 29 35 22 39 40 21 82 -22 35 15 48 35 43 24 34 54 2 36 5 17 78 0 0 35 43 58 22 39 41 22 82 -22 35 30 11 35 57 45 35 8 28 36 19 35 79 0 0 35 58 2 22 39 42 23 83 -21 35 44 16 36 11 48 35 22 35 36 33 36 80 0 0 36 11 47 22 39 43 24 84 -20 35 58 3 36 25 33 35 36 24 36 47 19 81 0 0 36 25 15 22 39 44 25 84 -19 36 11 32 36 38 59 35 49 55 37 0 44 82 0 0 36 38 25 22 39 45 26 85 -18 36 24 43 36 52 7 36 3 7 37 13 50 83 0 0 36 51 16 22 39 46 26 86 -17 36 37 35 37 4 57 36 16 1 37 26 38 84 0 0 37 3 48 22 39 47 27 86 -17 36 50 9 37 17 29 36 28 37 37 39 8 85 0 0 37 16 3 22 39 48 28 87 -16 37 2 24 37 29 42 36 40 54 37 51 19 86 0 0 37 27 58 22 39 49 29 88 -15 37 14 21 37 41 36 36 52 53 38 3 12 87 0 0 37 39 35 22 39 51 30 88 -14 37 26 0 37 53 12 37 4 33 38 14 46 88 0 0 37 50 54 22 39 52 30 89 -13 37 37 19 38 4 30 37 15 54 38 26 1 89 0 0 38 1 54 22 39 53 31 90 -13 37 48 20 38 15 29 37 26 57 38 36 58 90 0 0 38 12 35 22 39 54 32 90 -12 37 59 3 38 26 9 37 37 41 38 47 37 91 0 0 38 22 58 22 39 56 33 91 -11 38 9 26 38 36 30 37 48 6 38 57 57 92 0 0 38 33 2 22 39 57 34 92 -10 38 19 31 38 46 33 37 58 13 39 7 58 93 0 0 38 42 47 22 39 59 34 93 -9 38 29 17 38 56 17 38 8 1 39 17 40 94 0 0 38 52 13 22 40 0 35 93 -8 38 38 45 39 5 43 38 17 30 39 27 4 95 0 0 39 1 21 22 40 1 36 94 -8 38 47 53 39 14 49 38 26 40 39 36 9 96 0 0 39 10 10 22 40 3 37 95 -7 38 56 43 39 23 37 38 35 31 39 44 56 97 0 0 39 18 40 22 40 4 37 96 -6 39 5 14 39 32 6 38 44 4 39 53 23 98 0 0 39 26 51 22 40 6 38 97 -5 39 13 27 39 40 17 38 52 18 40 1 32 99 0 0 39 34 44 22 40 7 39 97 -5 39 21 20 39 48 9 39 0 12 40 9 23 100 0 0 39 42 18 22 40 9 40 98 -4 39 28 55 39 55 42 39 7 48 40 16 54 101 0 0 39 49 33 22 40 10 40 99 -3 39 36 11 40 2 56 39 15 6 40 24 7 102 0 0 39 56 29 22 40 12 41 100 -2 39 43 8 40 9 52 39 22 4 40 31 2 103 0 0 40 3 7 22 40 13 42 101 -1 39 49 46 40 16 28 39 28 44 40 37 37 104 0 0 40 9 26 22 40 15 43 102 -1 39 56 6 40 22 47 39 35 4 40 43 54 Uncertainty in time = +/- 1 secs [Prediction of 2008 Nov 16.0] Data for the target star ------------------------ * name: HIP 39644 * constellation : Cancer * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 08 06 04.1522 DE: +18 44 47.040 * position source: mpos:HIP2 pm:HIP2 plx:HIP2 * standard error: RA,DE ["]: ( .022, .016 ) * V mag [mag]: 8.8 * B mag [mag]: 9.0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (113) Amalthea approx. diameter [km]: 46 approx. diameter ["]: .021 distance from Earth [AU]: 2.97300 * orbital information: orbit source: Preston date of fit: 2008 Apr 25 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 953 number of rejected observations: 138 time covered by the observations: 1900 Jan 25 - 2007 Jul 10 1 sigma uncertainty ellipse (major, minor, PA): 0.008, 0.005, 97° remarks: * orbital elements for (113) Amalthea : Mean anomaly = 269.81549112 deg Arg. of pericenter = 78.46704553 deg Long. of node = 123.57131405 deg Inclination = 5.03934896 deg Eccentricity = 0.08812661 Semimajor axis = 2.37581181 AU Perihelion dist = 2.16643957 AU Mag: H = 8.62, G = 0.35 Epoch of elements : MJD 55082.94600000 TDT (2009 Sep 08.946) ------ occelmnt file for Occult BEGIN ----------------------------------- 2009 Sep 8 113 Amalthea 22h 42.1m UT 8.8 8 6 4.152 18 44 47.04HIP 39644 9.0 13.7 46 1.2 2.973 4.469 -11.53 152.8804 18.750 -161.14 5.36 22.7008 0.06097 0.33117 21.45596 -3.89751 -0.00389 0.00072 2000 269.0225902009 9 6.00000 78.467046123.571314 5.0393490.08812661 2.3758118 2.1664396 8.7 5.00.35 RATE 2.6914490 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.023 0.016 91 1.79 0.017 0 54786.5020090908__39644 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Nov 16, 16:55 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org