IOTA/IOTA-ES occultation update for (464) Megaira / TYC 1387-01235-1 event on 2008 Oct 11, 04:14 UT Visible from W Africa Summary ------- On 2008 Oct 11 UT, the 74 km diameter asteroid (464) Megaira will occult a 10.0 mag star in the constellation Cancer for observers along a path across W Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.1 mag to 15.1 mag (the magnitude of the asteroid) for at most 3.2 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: UCAC. The event at a glimpse ---------------------- * Rank: 88 * date and approx. time of event: 2008 Oct 11, 04:09 - 2008 Oct 11, 04:12 UT * midpoint of event [JD]: 2454750.67652083 * magnitude of target star: 10.0 * magnitude drop [mag]: 5.1 * estimated maximum duration [s]: 3.2 * Moon: 85 % sunlit, 152° distance * Sun: 74° distance * rough path description: W Africa The occultation path -------------------- * approximate projected width [km]: 74 * 1 sigma uncertainty interval [path widths]: +/- 0.55 * 1 sigma uncertainty interval [seconds]: +/- 2.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .023 +/- .019) * 1 sigma uncertainty ellipse (major, minor, PA): ( .023", .019", 91° ) * approx speed of asteroid's shadow [km/s]: 22.8266 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 1387-01235-1 by 464 Megaira on 2008 Oct 11 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 - 48 0 0 8 45 48 4 9 32 1 70 -72 8 24 26 9 7 9 8 0 57 9 30 40 - 47 0 0 9 7 3 4 9 32 2 71 -71 8 45 43 9 28 24 8 22 15 9 51 54 - 46 0 0 9 28 11 4 9 33 3 71 -70 9 6 51 9 49 31 8 43 24 10 13 0 - 45 0 0 9 49 11 4 9 33 4 71 -69 9 27 52 10 10 30 9 4 26 10 33 58 - 44 0 0 10 10 2 4 9 33 5 71 -68 9 48 44 10 31 21 9 25 19 10 54 48 - 43 0 0 10 30 44 4 9 34 6 71 -67 10 9 27 10 52 2 9 46 3 11 15 28 - 42 0 0 10 51 17 4 9 34 7 71 -66 10 30 1 11 12 34 10 6 37 11 35 59 - 41 0 0 11 11 40 4 9 35 8 72 -65 10 50 24 11 32 55 10 27 2 11 56 19 - 40 0 0 11 31 52 4 9 36 9 72 -64 11 10 38 11 53 7 10 47 17 12 16 30 - 39 0 0 11 51 54 4 9 37 10 72 -63 11 30 41 12 13 8 11 7 21 12 36 29 - 38 0 0 12 11 44 4 9 38 11 72 -62 11 50 32 12 32 57 11 27 14 12 56 18 - 37 0 0 12 31 24 4 9 39 12 72 -61 12 10 13 12 52 35 11 46 55 13 15 54 - 36 0 0 12 50 51 4 9 40 13 73 -60 12 29 41 13 12 1 12 6 25 13 35 19 - 35 0 0 13 10 6 4 9 41 14 73 -59 12 48 57 13 31 15 12 25 42 13 54 31 - 34 0 0 13 29 8 4 9 42 15 73 -58 13 8 0 13 50 16 12 44 47 14 13 31 - 33 0 0 13 47 57 4 9 44 16 73 -57 13 26 51 14 9 3 13 3 38 14 32 17 - 32 0 0 14 6 33 4 9 45 17 74 -56 13 45 28 14 27 38 13 22 17 14 50 50 - 31 0 0 14 24 55 4 9 47 18 74 -55 14 3 51 14 45 59 13 40 42 15 9 10 - 30 0 0 14 43 3 4 9 48 19 74 -54 14 22 0 15 4 5 13 58 53 15 27 15 - 29 0 0 15 0 56 4 9 50 20 74 -53 14 39 55 15 21 58 14 16 49 15 45 6 - 28 0 0 15 18 35 4 9 52 21 75 -52 14 57 36 15 39 35 14 34 31 16 2 42 - 27 0 0 15 35 59 4 9 54 23 75 -51 15 15 1 15 56 58 14 51 58 16 20 3 - 26 0 0 15 53 8 4 9 55 24 75 -50 15 32 11 16 14 5 15 9 9 16 37 8 - 25 0 0 16 10 1 4 9 57 25 76 -49 15 49 6 16 30 57 15 26 5 16 53 59 - 24 0 0 16 26 38 4 10 0 26 76 -48 16 5 44 16 47 33 15 42 46 17 10 33 - 23 0 0 16 42 59 4 10 2 27 76 -47 16 22 7 17 3 52 15 59 10 17 26 51 - 22 0 0 16 59 4 4 10 4 28 76 -46 16 38 13 17 19 56 16 15 18 17 42 53 - 21 0 0 17 14 53 4 10 6 29 77 -45 16 54 3 17 35 43 16 31 9 17 58 38 - 20 0 0 17 30 24 4 10 9 30 77 -44 17 9 36 17 51 13 16 46 44 18 14 6 - 19 0 0 17 45 39 4 10 11 31 77 -43 17 24 52 18 6 26 17 2 1 18 29 18 - 18 0 0 18 0 36 4 10 14 32 78 -42 17 39 51 18 21 21 17 17 1 18 44 12 - 17 0 0 18 15 15 4 10 16 33 78 -41 17 54 32 18 35 59 17 31 44 18 58 49 - 16 0 0 18 29 37 4 10 19 33 78 -40 18 8 55 18 50 20 17 46 9 19 13 8 - 15 0 0 18 43 42 4 10 21 34 79 -39 18 23 1 19 4 23 18 0 16 19 27 9 - 14 0 0 18 57 28 4 10 24 35 79 -38 18 36 48 19 18 8 18 14 6 19 40 52 - 13 0 0 19 10 56 4 10 27 36 79 -37 18 50 18 19 31 34 18 27 37 19 54 17 - 12 0 0 19 24 5 4 10 30 37 80 -36 19 3 29 19 44 42 18 40 49 20 7 23 - 11 0 0 19 36 56 4 10 33 38 80 -35 19 16 21 19 57 32 18 53 43 20 20 11 - 10 0 0 19 49 29 4 10 36 39 81 -34 19 28 55 20 10 3 19 6 18 20 32 41 - 9 0 0 20 1 42 4 10 39 40 81 -33 19 41 10 20 22 15 19 18 35 20 44 51 - 8 0 0 20 13 37 4 10 42 41 81 -32 19 53 6 20 34 8 19 30 32 20 56 43 - 7 0 0 20 25 12 4 10 45 42 82 -31 20 4 43 20 45 42 19 42 10 21 8 16 - 6 0 0 20 36 29 4 10 48 43 82 -31 20 16 0 20 56 57 19 53 29 21 19 29 - 5 0 0 20 47 25 4 10 52 44 82 -30 20 26 58 21 7 53 20 4 29 21 30 24 - 4 0 0 20 58 3 4 10 55 45 83 -29 20 37 37 21 18 29 20 15 9 21 40 58 - 3 0 0 21 8 21 4 10 58 46 83 -28 20 47 56 21 28 46 20 25 30 21 51 14 - 2 0 0 21 18 19 4 11 2 47 84 -27 20 57 56 21 38 43 20 35 31 22 1 10 - 1 0 0 21 27 58 4 11 5 48 84 -26 21 7 36 21 48 20 20 45 12 22 10 46 0 0 0 21 37 17 4 11 9 49 85 -25 21 16 56 21 57 38 20 54 33 22 20 2 1 0 0 21 46 16 4 11 12 50 85 -24 21 25 56 22 6 36 21 3 34 22 28 59 2 0 0 21 54 55 4 11 16 51 86 -23 21 34 36 22 15 14 21 12 16 22 37 35 3 0 0 22 3 13 4 11 19 52 86 -22 21 42 56 22 23 32 21 20 37 22 45 52 4 0 0 22 11 12 4 11 23 53 86 -21 21 50 56 22 31 29 21 28 38 22 53 49 5 0 0 22 18 51 4 11 27 54 87 -20 21 58 35 22 39 7 21 36 18 23 1 25 6 0 0 22 26 9 4 11 31 55 87 -19 22 5 54 22 46 24 21 43 39 23 8 41 7 0 0 22 33 7 4 11 34 56 88 -18 22 12 53 22 53 21 21 50 39 23 15 38 8 0 0 22 39 45 4 11 38 57 88 -17 22 19 32 22 59 58 21 57 18 23 22 13 9 0 0 22 46 2 4 11 42 58 89 -16 22 25 50 23 6 15 22 3 37 23 28 29 10 0 0 22 51 59 4 11 46 58 89 -15 22 31 48 23 12 11 22 9 36 23 34 24 11 0 0 22 57 36 4 11 50 59 90 -14 22 37 25 23 17 46 22 15 14 23 39 59 12 0 0 23 2 51 4 11 54 60 91 -14 22 42 42 23 23 2 22 20 31 23 45 13 13 0 0 23 7 47 4 11 58 61 91 -13 22 47 38 23 27 56 22 25 28 23 50 7 14 0 0 23 12 21 4 12 2 62 92 -12 22 52 13 23 32 30 22 30 4 23 54 41 15 0 0 23 16 36 4 12 6 63 92 -11 22 56 28 23 36 44 22 34 19 23 58 54 16 0 0 23 20 29 4 12 10 64 93 -10 23 0 22 23 40 37 22 38 14 24 2 46 17 0 0 23 24 2 4 12 14 65 94 -9 23 3 55 23 44 9 22 41 48 24 6 18 18 0 0 23 27 14 4 12 18 66 94 -8 23 7 7 23 47 21 22 45 1 24 9 29 19 0 0 23 30 5 4 12 23 67 95 -7 23 9 59 23 50 12 22 47 53 24 12 19 20 0 0 23 32 36 4 12 27 68 96 -6 23 12 30 23 52 42 22 50 24 24 14 49 21 0 0 23 34 46 4 12 31 69 96 -5 23 14 40 23 54 52 22 52 35 24 16 58 22 0 0 23 36 35 4 12 35 70 97 -4 23 16 30 23 56 40 22 54 24 24 18 47 23 0 0 23 38 3 4 12 40 70 98 -3 23 17 58 23 58 8 22 55 53 24 20 15 24 0 0 23 39 11 4 12 44 71 99 -2 23 19 6 23 59 16 22 57 1 24 21 22 25 0 0 23 39 57 4 12 48 72 100 -1 23 19 52 24 0 2 22 57 48 24 22 8 26 0 0 23 40 23 4 12 53 73 101 -1 23 20 18 24 0 28 22 58 14 24 22 34 Uncertainty in time = +/- 2 secs [Prediction of 2008 Aug 6.0] Data for the target star ------------------------ * name: TYC 1387-01235-1 * constellation : Cancer * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 08 26 25.7414 DE: +19 31 32.465 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .017, .016 ) * V mag [mag]: 10.0 * B mag [mag]: 10.8 * Apparent position with proper motion RA(deg): 126.7356414496 DE(deg): 19.4976705720 * Equation of equinoxes (radians) : 0.000049272015638 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (464) Megaira approx. diameter [km]: 74 approx. diameter ["]: .035 distance from Earth [AU]: 2.93100 * orbital information: orbit source: Preston date of fit: 2008 Aug 06 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 670 number of rejected observations: 85 time covered by the observations: 1901 Jan 09 - 2008 Feb 28 1 sigma uncertainty ellipse (major, minor, PA): 0.016, 0.010, 93° remarks: * orbital elements for (464) Megaira : Mean anomaly = 80.17249372 deg Arg. of pericenter = 258.55428777 deg Long. of node = 102.43534311 deg Inclination = 10.16256276 deg Eccentricity = 0.20215070 Semimajor axis = 2.80456307 AU Perihelion dist = 2.23761868 AU Mag: H = 9.58, G = 0.15 Epoch of elements : MJD 54750.17600000 TDT (2008 Oct 11.176) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Oct 11 464 Megaira 4h 14.2m UT 10.0 8 26 25.741 19 31 32.46TYC 1387-01235-1 10.8 15.1 74 3.2 2.931 2.721 -3.83 42.9299 19.527 113.13 -7.15 4.2365 0.00666 0.05632 12.82037 -1.27836 -0.00538 0.00132 2000 80.13556120081011.00000258.554288102.435343 10.1625630.20215070 2.8045631 2.2376187 9.5 5.00.15 RATE 2.0984870 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.023 0.019 91 1.55 0.019 0 54684.5020081011_1235-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Sep 11, 16:21 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org