IOTA/IOTA-ES occultation update for (127) Johanna / 2UCAC 19776031 event on 2008 Mar 28, 10:24 UT Visible from Ecuador Summary ------- On 2008 Mar 28 UT, the 123 km diameter asteroid (127) Johanna will occult a 12.2 mag star in the constellation Sagittarius for observers along a path across Ecuador. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.8 mag to 13.8 mag (the magnitude of the asteroid) for at most 6.5 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: 85 * date and approx. time of event: 2008 Mar 28, 10:19 - 2008 Mar 28, 10:23 UT * midpoint of event [JD]: 2454553.93380833 * magnitude of target star: 12.2 * magnitude drop [mag]: 1.8 * estimated maximum duration [s]: 6.5 * Moon: 64 % sunlit, 21° distance * Sun: 86° distance * rough path description: Ecuador The occultation path -------------------- * approximate projected width [km]: 129 * 1 sigma uncertainty interval [path widths]: +/- 0.60 * 1 sigma uncertainty interval [seconds]: +/- 3.7 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .040 +/- .037) * 1 sigma uncertainty ellipse (major, minor, PA): ( .040", .037", 90° ) * approx speed of asteroid's shadow [km/s]: 19.0926 * website for maps: http://lunar-occultations.com/iota/asteroids/astrndx.htm http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 19776031 by 127 Johanna on 2008 Mar 28 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 -133 0 0 21 23 46 10 19 23 1 122 -58 20 42 44 22 4 59 19 53 43 .. .. .. -132 0 0 20 48 37 10 19 23 2 123 -58 20 7 34 21 29 50 19 18 31 22 19 33 -131 0 0 20 13 17 10 19 23 3 123 -58 19 32 14 20 54 31 18 43 11 21 44 15 -130 0 0 19 37 49 10 19 23 4 123 -57 18 56 46 20 19 3 18 7 43 21 8 47 -129 0 0 19 2 14 10 19 24 5 124 -57 18 21 11 19 43 28 17 32 9 20 33 11 -128 0 0 18 26 33 10 19 25 6 124 -57 17 45 31 19 7 46 16 56 29 19 57 29 -127 0 0 17 50 47 10 19 25 7 124 -56 17 9 45 18 31 59 16 20 44 19 21 41 -126 0 0 17 14 57 10 19 26 9 125 -56 16 33 56 17 56 8 15 44 56 18 45 48 -125 0 0 16 39 3 10 19 28 10 125 -55 15 58 4 17 20 13 15 9 6 18 9 52 -124 0 0 16 3 9 10 19 29 11 125 -55 15 22 11 16 44 17 14 33 15 17 33 53 -123 0 0 15 27 14 10 19 30 12 125 -54 14 46 18 16 8 20 13 57 24 16 57 54 -122 0 0 14 51 19 10 19 32 13 126 -54 14 10 26 15 32 23 13 21 35 16 21 55 -121 0 0 14 15 27 10 19 33 14 126 -53 13 34 36 14 56 28 12 45 48 15 45 57 -120 0 0 13 39 38 10 19 35 15 126 -53 12 58 50 14 20 36 12 10 5 15 10 1 -119 0 0 13 3 53 10 19 37 17 126 -52 12 23 8 13 44 48 11 34 26 14 34 10 -118 0 0 12 28 13 10 19 39 18 127 -51 11 47 31 13 9 6 10 58 54 13 58 23 -117 0 0 11 52 40 10 19 41 19 127 -51 11 12 2 12 33 29 10 23 29 13 22 42 -116 0 0 11 17 15 10 19 44 20 127 -50 10 36 41 11 58 0 9 48 12 12 47 9 -115 0 0 10 41 59 10 19 46 21 127 -49 10 1 29 11 22 40 9 13 5 12 11 44 -114 0 0 10 6 54 10 19 49 22 128 -48 9 26 27 10 47 30 8 38 8 11 36 28 -113 0 0 9 31 59 10 19 51 23 128 -47 8 51 37 10 12 31 8 3 23 11 1 24 -112 0 0 8 57 16 10 19 54 25 128 -47 8 16 59 9 37 44 7 28 51 10 26 31 -111 0 0 8 22 48 10 19 57 26 128 -46 7 42 35 9 3 10 6 54 33 9 51 51 -110 0 0 7 48 33 10 20 0 27 129 -45 7 8 26 8 28 51 6 20 29 9 17 25 -109 0 0 7 14 34 10 20 4 28 129 -44 6 34 32 7 54 46 5 46 42 8 43 15 -108 0 0 6 40 52 10 20 7 29 129 -43 6 0 55 7 20 59 5 13 11 8 9 20 -107 0 0 6 7 27 10 20 10 30 129 -42 5 27 36 6 47 28 4 39 59 7 35 43 -106 0 0 5 34 21 10 20 14 31 130 -41 4 54 36 6 14 16 4 7 5 7 2 24 -105 0 0 5 1 34 10 20 18 32 130 -41 4 21 55 5 41 24 3 34 31 6 29 25 -104 0 0 4 29 8 10 20 22 34 130 -40 3 49 34 5 8 51 3 2 18 5 56 45 -103 0 0 3 57 3 10 20 25 35 130 -39 3 17 35 4 36 40 2 30 26 5 24 26 -102 0 0 3 25 20 10 20 30 36 131 -38 2 45 59 4 4 51 1 58 57 4 52 29 -101 0 0 2 54 0 10 20 34 37 131 -37 2 14 45 3 33 25 1 27 51 4 20 55 -100 0 0 2 23 4 10 20 38 38 131 -36 1 43 55 3 2 22 0 57 9 3 49 45 - 99 0 0 1 52 32 10 20 42 39 131 -35 1 13 30 2 31 44 0 26 51 3 18 58 - 98 0 0 1 22 25 10 20 47 40 132 -34 0 43 30 2 1 30 - 0 3 1 2 48 37 - 97 0 0 0 52 45 10 20 51 41 132 -33 0 13 56 1 31 43 - 0 32 28 2 18 42 - 96 0 0 0 23 31 10 20 56 42 132 -32 - 0 15 12 1 2 22 - 1 1 27 1 49 12 - 95 0 0 - 0 5 16 10 21 0 43 133 -31 - 0 43 52 0 33 28 - 1 30 0 1 20 11 - 94 0 0 - 0 33 36 10 21 5 45 133 -30 - 1 12 5 0 5 2 - 1 58 4 0 51 36 - 93 0 0 - 1 1 26 10 21 10 46 133 -29 - 1 39 49 - 0 22 55 - 2 25 40 0 23 30 - 92 0 0 - 1 28 48 10 21 15 47 134 -28 - 2 7 4 - 0 50 24 - 2 52 48 - 0 4 7 - 91 0 0 - 1 55 41 10 21 20 48 134 -27 - 2 33 50 - 1 17 23 - 3 19 26 - 0 31 14 - 90 0 0 - 2 22 4 10 21 25 49 134 -26 - 3 0 6 - 1 43 53 - 3 45 34 - 0 57 52 - 89 0 0 - 2 47 56 10 21 30 50 135 -25 - 3 25 52 - 2 9 52 - 4 11 12 - 1 23 59 - 88 0 0 - 3 13 18 10 21 35 51 135 -24 - 3 51 7 - 2 35 21 - 4 36 19 - 1 49 36 - 87 0 0 - 3 38 9 10 21 41 52 136 -23 - 4 15 51 - 3 0 18 - 5 0 55 - 2 14 42 - 86 0 0 - 4 2 28 10 21 46 53 136 -22 - 4 40 4 - 3 24 44 - 5 25 0 - 2 39 16 - 85 0 0 - 4 26 16 10 21 51 54 137 -21 - 5 3 45 - 3 48 38 - 5 48 33 - 3 3 18 - 84 0 0 - 4 49 31 10 21 57 55 137 -20 - 5 26 54 - 4 12 0 - 6 11 35 - 3 26 48 - 83 0 0 - 5 12 14 10 22 2 56 138 -19 - 5 49 31 - 4 34 50 - 6 34 4 - 3 49 45 - 82 0 0 - 5 34 25 10 22 8 57 139 -18 - 6 11 35 - 4 57 7 - 6 56 0 - 4 12 9 - 81 0 0 - 5 56 2 10 22 13 58 139 -17 - 6 33 6 - 5 18 50 - 7 17 24 - 4 34 1 - 80 0 0 - 6 17 7 10 22 19 59 140 -16 - 6 54 5 - 5 40 1 - 7 38 16 - 4 55 19 - 79 0 0 - 6 37 38 10 22 24 59 141 -15 - 7 14 30 - 6 0 38 - 7 58 34 - 5 16 4 - 78 0 0 - 6 57 36 10 22 30 60 142 -14 - 7 34 22 - 6 20 42 - 8 18 19 - 5 36 15 - 77 0 0 - 7 17 0 10 22 36 61 143 -13 - 7 53 40 - 6 40 12 - 8 37 30 - 5 55 52 - 76 0 0 - 7 35 50 10 22 42 62 144 -12 - 8 12 25 - 6 59 8 - 8 56 8 - 6 14 55 - 75 0 0 - 7 54 7 10 22 47 63 145 -11 - 8 30 36 - 7 17 30 - 9 14 12 - 6 33 24 - 74 0 0 - 8 11 50 10 22 53 64 146 -10 - 8 48 13 - 7 35 18 - 9 31 43 - 6 51 19 - 73 0 0 - 8 28 58 10 22 59 64 147 -9 - 9 5 16 - 7 52 32 - 9 48 40 - 7 8 39 - 72 0 0 - 8 45 32 10 23 5 65 149 -8 - 9 21 45 - 8 9 12 -10 5 3 - 7 25 25 - 71 0 0 - 9 1 32 10 23 10 66 150 -7 - 9 37 40 - 8 25 17 -10 20 52 - 7 41 36 - 70 0 0 - 9 16 58 10 23 16 67 152 -6 - 9 53 1 - 8 40 47 -10 36 7 - 7 57 12 - 69 0 0 - 9 31 49 10 23 22 67 154 -5 -10 7 48 - 8 55 44 -10 50 48 - 8 12 14 - 68 0 0 - 9 46 6 10 23 28 68 155 -4 -10 22 0 - 9 10 5 -11 4 55 - 8 26 41 - 67 0 0 - 9 59 49 10 23 34 69 157 -3 -10 35 38 - 9 23 52 -11 18 28 - 8 40 34 - 66 0 0 -10 12 57 10 23 40 69 159 -2 -10 48 42 - 9 37 4 -11 31 27 - 8 53 51 - 65 0 0 -10 25 30 10 23 46 70 162 -1 -11 1 11 - 9 49 42 -11 43 51 - 9 6 34 Uncertainty in time = +/- 4 secs [Prediction of 2008 Feb 14.0] Data for the target star ------------------------ * name: 2UCAC 19776031 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 56 58.4115 DE: -29 27 06.376 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .037, .035 ) * V mag [mag]: 12.2 * B mag [mag]: 0.0 * Apparent position with proper motion RA(deg): 284.3765407338 DE(deg): -29.4417433561 * Equation of equinoxes (radians) : 0.000040908584579 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (127) Johanna approx. diameter [km]: 123 approx. diameter ["]: .061 distance from Earth [AU]: 2.78500 * orbital information: orbit source: Preston date of fit: 2008 Feb 13 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 690 number of rejected observations: 98 time covered by the observations: 1917 Oct 03 - 2007 Aug 07 1 sigma uncertainty ellipse (major, minor, PA): 0.015, 0.010, 87° remarks: * orbital elements for (127) Johanna : Mean anomaly = 133.60094043 deg Arg. of pericenter = 92.40764044 deg Long. of node = 31.42403705 deg Inclination = 8.23885570 deg Eccentricity = 0.06368077 Semimajor axis = 2.75810482 AU Perihelion dist = 2.58246658 AU Mag: H = 8.49, G = 0.15 Epoch of elements : MJD 54553.43400000 TDT (2008 Mar 28.434) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Mar 28 127 Johanna 10h 24.7m UT 12.2 18 56 58.412-29 27 6.382UCAC 19776031 0.0 13.8 123 6.5 2.785 2.583 -4.36 -58.1375 -29.450 25.08 3.22 10.4114 0.04037 0.30191 10.68772 -1.37972 -0.00573 -0.00062 2000 132.8620362008 325.00000 92.407640 31.424037 8.2388560.06368077 2.7581048 2.5824666 8.3 5.00.15 RATE 2.1517300 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.040 0.037 90 1.60 0.037 0 54510.5020080328_776031 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Feb 14, 20:02 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org