IOTA/IOTA-ES occultation update for (38) Leda / TYC 1784-00117-1 event on 2009 Jul 04, 02:28 UT Visible from Summary ------- On 2009 Jul 04 UT, the 116 km diameter asteroid (38) Leda will occult a 10.4 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 3.4 mag to 13.7 mag (the magnitude of the asteroid) for at most 3.0 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: 63 * date and approx. time of event: 2009 Jul 04, 02:26 - 2009 Jul 04, 02:27 UT * magnitude of target star: 10.4 * magnitude drop [mag]: 3.4 * estimated maximum duration [s]: 3.0 * Moon: 90 % sunlit, 167° distance * Sun: 50° distance * rough path description: The occultation path -------------------- * approximate projected width [km]: 174 * 1 sigma uncertainty interval [path widths]: +/- 0.97 * 1 sigma uncertainty interval [seconds]: +/- 1.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .024 +/- .052) * 1 sigma uncertainty ellipse (major, minor, PA): ( .052", .024", 360° ) * approx speed of asteroid's shadow [km/s]: 38.1357 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 1784-00117-1 by 38 Leda on 2009 Jul 4 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 - 12 47 12 29 0 0 2 26 41 1 63 -34 - 10 55 10 ... .. .. ... .. .. ... .. .. - 10 43 10 30 0 0 2 26 42 3 64 -32 - 8 54 26 - 12 35 50 ... .. .. ... .. .. Latitude Latitude Latitude Latitude - 10 0 0 30 21 30 2 26 42 4 64 -31 29 27 7 31 17 2 .. .. .. 33 8 22 - 9 0 0 30 51 55 2 26 42 5 65 -31 29 57 11 31 47 48 .. .. .. 33 39 55 - 8 0 0 31 22 55 2 26 43 6 65 -30 30 27 51 32 19 11 .. .. .. 34 12 7 - 7 0 0 31 54 31 2 26 43 7 66 -29 30 59 5 32 51 10 .. .. .. 34 44 54 - 6 0 0 32 26 41 2 26 44 8 66 -28 31 30 53 33 23 43 .. .. .. 35 18 18 - 5 0 0 32 59 25 2 26 44 9 67 -27 32 3 15 33 56 51 .. .. .. 35 52 17 - 4 0 0 33 32 42 2 26 45 10 68 -26 32 36 9 34 30 32 30 49 46 36 26 50 - 3 0 0 34 6 30 2 26 46 11 68 -25 33 9 34 35 4 45 31 22 31 37 1 56 - 2 0 0 34 40 49 2 26 47 12 69 -24 33 43 30 35 39 29 31 55 46 37 37 34 - 1 0 0 35 15 39 2 26 48 13 69 -23 34 17 56 36 14 43 32 29 30 38 13 43 0 0 0 35 50 57 2 26 49 14 70 -22 34 52 50 36 50 27 33 3 42 38 50 22 1 0 0 36 26 42 2 26 50 15 71 -21 35 28 12 37 26 38 33 38 21 39 27 30 2 0 0 37 2 54 2 26 51 16 71 -21 36 4 0 38 3 17 34 13 27 40 5 5 3 0 0 37 39 32 2 26 52 17 72 -20 36 40 13 38 40 20 34 48 57 40 43 6 4 0 0 38 16 33 2 26 53 17 73 -19 37 16 49 39 17 48 35 24 50 41 21 32 5 0 0 38 53 57 2 26 55 18 74 -18 37 53 49 39 55 39 36 1 6 42 0 21 6 0 0 39 31 42 2 26 56 19 74 -17 38 31 9 40 33 51 36 37 43 42 39 32 7 0 0 40 9 47 2 26 58 20 75 -16 39 8 49 41 12 22 37 14 40 43 19 2 8 0 0 40 48 10 2 26 59 21 76 -15 39 46 47 41 51 12 37 51 54 43 58 51 9 0 0 41 26 49 2 27 1 22 77 -14 40 25 1 42 30 18 38 29 26 44 38 56 10 0 0 42 5 43 2 27 3 23 78 -13 41 3 31 43 9 39 39 7 13 45 19 16 11 0 0 42 44 50 2 27 4 24 79 -12 41 42 14 43 49 12 39 45 13 45 59 49 12 0 0 43 24 9 2 27 6 25 79 -11 42 21 8 44 28 58 40 23 25 46 40 32 13 0 0 44 3 37 2 27 8 25 80 -10 43 0 13 45 8 52 41 1 48 47 21 25 14 0 0 44 43 14 2 27 10 26 81 -9 43 39 25 45 48 54 41 40 20 48 2 24 15 0 0 45 22 56 2 27 12 27 82 -8 44 18 44 46 29 1 42 18 59 48 43 28 16 0 0 46 2 42 2 27 14 28 83 -7 44 58 7 47 9 12 42 57 43 49 24 34 17 0 0 46 42 30 2 27 16 29 84 -6 45 37 33 47 49 24 43 36 30 50 5 41 18 0 0 47 22 18 2 27 18 29 85 -5 46 17 0 48 29 36 44 15 19 50 46 46 19 0 0 48 2 4 2 27 20 30 87 -4 46 56 25 49 9 45 44 54 9 51 27 47 20 0 0 48 41 47 2 27 22 31 88 -3 47 35 47 49 49 50 45 32 56 52 8 42 21 0 0 49 21 23 2 27 24 31 89 -2 48 15 4 50 29 48 46 11 40 52 49 28 22 0 0 50 0 52 2 27 26 32 90 -1 48 54 14 51 9 37 46 50 18 53 30 3 23 0 0 50 40 11 2 27 28 33 91 0 49 33 15 51 49 15 47 28 49 54 10 26 Uncertainty in time = +/- 3 secs [Prediction of 2008 Apr 25.0] Data for the target star ------------------------ * name: TYC 1784-00117-1 * constellation : Aries * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 03 15 32.3224 DE: +23 58 00.247 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .018, .051 ) * V mag [mag]: 10.4 * B mag [mag]: 11.5 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (38) Leda approx. diameter [km]: 116 approx. diameter ["]: .052 distance from Earth [AU]: 3.08400 * orbital information: orbit source: Preston date of fit: 2008 Apr 25 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 909 number of rejected observations: 109 time covered by the observations: 1904 Sep 19 - 2007 Jul 12 1 sigma uncertainty ellipse (major, minor, PA): 0.016, 0.008, 78° remarks: * orbital elements for (38) Leda : Mean anomaly = 305.40445104 deg Arg. of pericenter = 169.76654626 deg Long. of node = 295.79036588 deg Inclination = 6.97297343 deg Eccentricity = 0.15369475 Semimajor axis = 2.73928063 AU Perihelion dist = 2.31826758 AU Mag: H = 8.36, G = 0.15 Epoch of elements : MJD 55016.10300000 TDT (2009 Jul 04.103) ------ occelmnt file for Occult BEGIN ----------------------------------- 2009 Jul 4 38 Leda 2h 28.5m UT 10.4 3 15 32.322 23 58 0.25TYC 1784-00117-1 11.5 13.7 116 3.0 3.084 4.282 17.95 89.5084 23.962 143.96 22.87 2.4757 -0.21733 0.71421 20.58394 6.29458 -0.00408 -0.00075 2000 304.0776902009 628.00000169.766546295.790366 6.9729730.15369475 2.7392806 2.3182676 8.3 5.00.15 RATE 2.1739490 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.052 0.024 360 1.97 0.050 0 54581.5020090704_0117-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Apr 25, 07:23 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org