IOTA/IOTA-ES occultation update for (4732) Froeschle / TYC 6144-00381-1 event on 2009 Apr 10, 18:42 UT Visible from Summary ------- On 2009 Apr 10 UT, the 30 km diameter asteroid (4732) Froeschle will occult a 10.1 mag star in the constellation Virgo for observers along a path across . In the case of an occultation, the combined light of the asteroid and the star will drop by 6.1 mag to 16.2 mag (the magnitude of the asteroid) for at most 2.1 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: 18 * date and approx. time of event: 2009 Apr 10, 18:39 - 2009 Apr 10, 18:46 UT * magnitude of target star: 10.1 * magnitude drop [mag]: 6.1 * estimated maximum duration [s]: 2.1 * Moon: 98 % sunlit, 2° distance * Sun: 165° distance * rough path description: The occultation path -------------------- * approximate projected width [km]: 64 * 1 sigma uncertainty interval [path widths]: +/- 3.77 * 1 sigma uncertainty interval [seconds]: +/- 9.7 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .090 +/- .053) * 1 sigma uncertainty ellipse (major, minor, PA): ( .091", .053", 94° ) * approx speed of asteroid's shadow [km/s]: 14.2259 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6144-00381-1 by 4732 Froeschle on 2009 Apr 10 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 109 55 16 69 0 0 18 46 6 0 200 -10 110 47 17 109 4 3 ... .. .. ... .. .. 109 3 28 68 0 0 18 46 5 1 199 -11 109 52 27 108 15 10 116 28 51 ... .. .. 108 21 57 67 0 0 18 46 5 3 198 -12 109 8 21 107 36 9 115 21 33 ... .. .. 107 49 13 66 0 0 18 46 4 4 198 -13 108 33 23 107 5 36 114 26 52 ... .. .. 107 24 5 65 0 0 18 46 3 5 197 -14 108 6 17 106 42 22 113 42 48 ... .. .. 107 5 35 64 0 0 18 46 1 6 197 -15 107 46 4 106 25 32 113 7 49 ... .. .. 106 52 56 63 0 0 18 46 0 7 197 -16 107 31 54 106 14 22 112 40 43 ... .. .. 106 45 30 62 0 0 18 45 58 8 197 -17 107 23 6 106 8 16 112 20 32 ... .. .. 106 42 45 61 0 0 18 45 55 8 197 -18 107 19 9 106 6 43 112 6 28 ... .. .. 106 44 16 60 0 0 18 45 53 9 197 -18 107 19 34 106 9 17 111 57 53 101 55 0 106 49 39 59 0 0 18 45 50 10 197 -19 107 23 59 106 15 38 111 54 16 102 8 6 106 58 37 58 0 0 18 45 47 11 197 -20 107 32 4 106 25 28 111 55 10 102 24 3 107 10 54 57 0 0 18 45 43 12 197 -21 107 43 34 106 38 31 112 0 14 102 42 39 107 26 16 56 0 0 18 45 40 13 198 -22 107 58 13 106 54 36 112 9 8 103 3 44 107 44 33 55 0 0 18 45 36 14 198 -22 108 15 52 107 13 31 112 21 39 103 27 10 108 5 36 54 0 0 18 45 31 15 198 -23 108 36 20 107 35 7 112 37 32 103 52 51 108 29 16 53 0 0 18 45 27 16 199 -24 108 59 30 107 59 18 112 56 38 104 20 42 108 55 28 52 0 0 18 45 22 17 199 -25 109 25 14 108 25 56 113 18 48 104 50 37 109 24 6 51 0 0 18 45 17 18 200 -25 109 53 29 108 54 59 113 43 56 105 22 34 109 55 7 50 0 0 18 45 11 18 201 -26 110 24 9 109 26 20 114 11 54 105 56 29 110 28 28 49 0 0 18 45 6 19 201 -27 110 57 12 109 59 59 114 42 41 106 32 21 111 4 7 48 0 0 18 45 0 20 202 -27 111 32 36 110 35 53 115 16 13 107 10 9 111 42 3 47 0 0 18 44 54 21 203 -28 112 10 19 111 14 1 115 52 29 107 49 52 112 22 15 46 0 0 18 44 47 21 203 -28 112 50 23 111 54 23 116 31 28 108 31 30 113 4 46 45 0 0 18 44 40 22 204 -29 113 32 47 112 37 1 117 13 13 109 15 5 113 49 37 44 0 0 18 44 33 23 205 -29 114 17 35 113 21 56 117 57 46 110 0 38 114 36 51 43 0 0 18 44 25 24 206 -30 115 4 48 114 9 10 118 45 10 110 48 11 115 26 32 42 0 0 18 44 18 24 207 -30 115 54 31 114 58 49 119 35 32 111 37 48 116 18 45 41 0 0 18 44 9 25 208 -30 116 46 50 115 50 57 120 28 59 112 29 32 117 13 36 40 0 0 18 44 1 25 209 -31 117 41 51 116 45 39 121 25 40 113 23 30 118 11 14 39 0 0 18 43 52 26 210 -31 118 39 42 117 43 5 122 25 48 114 19 46 119 11 49 38 0 0 18 43 43 26 211 -31 119 40 35 118 43 23 123 29 36 115 18 27 120 15 32 37 0 0 18 43 33 27 213 -31 120 44 40 119 46 45 124 37 24 116 19 43 121 22 39 36 0 0 18 43 23 27 214 -31 121 52 15 120 53 25 125 49 35 117 23 44 122 33 26 35 0 0 18 43 13 27 215 -31 123 3 37 122 3 40 127 6 38 118 30 42 123 48 16 34 0 0 18 43 2 28 217 -31 124 19 9 123 17 50 128 29 12 119 40 52 125 7 37 33 0 0 18 42 50 28 218 -30 125 39 21 124 36 22 129 58 6 120 54 30 126 32 2 32 0 0 18 42 39 28 220 -30 127 4 50 125 59 47 131 34 27 122 11 59 128 2 15 31 0 0 18 42 26 28 221 -29 128 36 23 127 28 47 133 19 48 123 33 45 129 39 17 30 0 0 18 42 13 28 223 -29 130 15 3 129 4 16 135 16 28 125 0 20 131 24 25 29 0 0 18 41 59 27 225 -28 132 2 19 130 47 27 137 28 1 126 32 27 133 19 34 28 0 0 18 41 45 27 226 -27 134 0 15 132 40 2 140 0 45 128 10 59 135 27 32 27 0 0 18 41 29 26 228 -26 136 12 5 134 44 31 143 7 37 129 57 9 Latitude Latitude Latitude Latitude 136 0 0 26 45 52 18 41 25 26 229 -25 27 5 12 26 26 45 29 39 16 24 9 6 137 0 0 26 20 52 18 41 18 26 230 -25 26 39 59 26 1 57 29 12 7 23 45 41 138 0 0 25 57 18 18 41 11 25 231 -24 26 16 13 25 38 35 28 46 36 23 23 35 139 0 0 25 35 10 18 41 5 25 231 -24 25 53 54 25 16 38 28 22 39 23 2 48 140 0 0 25 14 25 18 40 58 24 232 -23 25 33 0 24 56 3 28 0 16 22 43 18 141 0 0 24 55 4 18 40 52 24 233 -22 25 13 29 24 36 51 27 39 24 22 25 5 142 0 0 24 37 4 18 40 45 23 234 -21 24 55 21 24 18 59 27 20 3 22 8 7 143 0 0 24 20 26 18 40 39 23 234 -21 24 38 35 24 2 28 27 2 10 21 52 25 144 0 0 24 5 7 18 40 33 22 235 -20 24 23 9 23 47 16 26 45 44 21 37 58 145 0 0 23 51 8 18 40 28 22 236 -19 24 9 4 23 33 23 26 30 46 21 24 44 146 0 0 23 38 28 18 40 22 21 236 -18 23 56 18 23 20 48 26 17 12 21 12 45 147 0 0 23 27 6 18 40 17 20 237 -18 23 44 51 23 9 30 26 5 4 21 1 59 148 0 0 23 17 1 18 40 11 20 238 -17 23 34 43 22 59 30 25 54 19 20 52 25 149 0 0 23 8 14 18 40 6 19 238 -16 23 25 53 22 50 47 25 44 58 20 44 5 150 0 0 23 0 45 18 40 2 18 239 -15 23 18 20 22 43 20 25 37 0 20 36 57 151 0 0 22 54 32 18 39 57 18 239 -14 23 12 5 22 37 9 25 30 25 20 31 2 152 0 0 22 49 36 18 39 52 17 240 -13 23 7 7 22 32 15 25 25 13 20 26 19 153 0 0 22 45 57 18 39 48 16 240 -13 23 3 27 22 28 37 25 21 22 20 22 48 154 0 0 22 43 34 18 39 44 15 241 -12 23 1 4 22 26 15 25 18 55 20 20 29 155 0 0 22 42 28 18 39 40 14 241 -11 22 59 58 22 25 9 25 17 49 20 19 23 156 0 0 22 42 39 18 39 36 14 242 -10 23 0 9 22 25 19 25 18 6 20 19 29 157 0 0 22 44 7 18 39 33 13 242 -9 23 1 39 22 26 46 25 19 46 20 20 48 158 0 0 22 46 53 18 39 30 12 243 -8 23 4 26 22 29 30 25 22 49 20 23 19 159 0 0 22 50 56 18 39 27 11 243 -7 23 8 32 22 33 30 25 27 16 20 27 4 160 0 0 22 56 17 18 39 24 10 244 -6 23 13 56 22 38 49 25 33 6 20 32 3 161 0 0 23 2 57 18 39 21 9 244 -5 23 20 40 22 45 25 25 40 22 20 38 15 162 0 0 23 10 56 18 39 19 9 245 -4 23 28 43 22 53 20 25 49 3 .. .. .. 163 0 0 23 20 16 18 39 17 8 245 -4 23 38 7 23 2 35 25 59 10 .. .. .. 164 0 0 23 30 56 18 39 15 7 245 -3 23 48 53 23 13 9 26 10 45 .. .. .. 165 0 0 23 42 57 18 39 13 6 246 -2 24 1 1 23 25 4 26 23 48 .. .. .. 166 0 0 23 56 21 18 39 11 5 246 -1 24 14 32 23 38 21 26 38 21 .. .. .. Uncertainty in time = +/- 11 secs [Prediction of 2008 Apr 25.0] Data for the target star ------------------------ * name: TYC 6144-00381-1 * constellation : Virgo * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 13 58 20.2596 DE: -19 21 17.697 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .021, .022 ) * V mag [mag]: 10.1 * B mag [mag]: 10.8 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (4732) Froeschle approx. diameter [km]: 30 approx. diameter ["]: .017 distance from Earth [AU]: 2.38900 * orbital information: orbit source: Preston date of fit: 2008 Apr 24 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 697 number of rejected observations: 13 time covered by the observations: 1955 Oct 25 - 2008 Mar 08 1 sigma uncertainty ellipse (major, minor, PA): 0.088, 0.048, 94° remarks: * orbital elements for (4732) Froeschle : Mean anomaly = 196.51519875 deg Arg. of pericenter = 148.64555448 deg Long. of node = 226.52107056 deg Inclination = 16.85615713 deg Eccentricity = 0.06820400 Semimajor axis = 3.15902326 AU Perihelion dist = 2.94356525 AU Mag: H = 11.27, G = 0.15 Epoch of elements : MJD 54931.78000000 TDT (2009 Apr 10.780) ------ occelmnt file for Occult BEGIN ----------------------------------- 2009 Apr 10 4732 Froeschle 18h 42.6m UT 10.1 13 58 20.260-19 21 17.70TYC 6144-00381-1 10.8 16.2 30 2.1 2.389 -1.710 16.99 89.7994 -19.359 -100.35 8.21 18.7105 0.50745 0.72240 -6.57186 4.61336 -0.00103 0.00110 2000 196.2027392009 4 9.00000148.645554226.521071 16.8561570.06820400 3.1590233 2.943565211.3 5.00.15 RATE 1.7553950 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.091 0.053 94 4.77 0.065 0 54581.5020090410_0381-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Apr 25, 06:20 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org