IOTA/IOTA-ES occultation update for (227) Philosophia / TYC 1901-01118-1 event on 2008 May 04, 12:11 UT Visible from Japan, E Russia Summary ------- On 2008 May 04 UT, the 87 km diameter asteroid (227) Philosophia will occult a 11.3 mag star in the constellation Gemini for observers along a path across Japan, E Russia. In the case of an occultation, the combined light of the asteroid and the star will drop by 3.7 mag to 15.0 mag (the magnitude of the asteroid) for at most 2.9 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC. The event at a glimpse ---------------------- * Rank: 83 * date and approx. time of event: 2008 May 04, 12:12 - 2008 May 04, 12:13 UT * midpoint of event [JD]: 2454591.00765 * magnitude of target star: 11.3 * magnitude drop [mag]: 3.7 * estimated maximum duration [s]: 2.9 * Moon: 2 % sunlit, 70° distance * Sun: 57° distance * rough path description: Japan, E Russia The occultation path -------------------- * approximate projected width [km]: 116 * 1 sigma uncertainty interval [path widths]: +/- 0.64 * 1 sigma uncertainty interval [seconds]: +/- 2.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .030 +/- .020) * 1 sigma uncertainty ellipse (major, minor, PA): ( .030", .020", 92° ) * approx speed of asteroid's shadow [km/s]: 30.4088 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 1901-01118-1 by 227 Philosophia on 2008 May 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 ' " Latitude Latitude Latitude Latitude 112 0 0 55 10 36 12 12 13 42 258 -1 54 29 14 55 52 33 53 37 6 56 47 8 113 0 0 54 40 34 12 12 15 41 260 -1 53 59 6 55 22 36 53 6 51 56 17 20 114 0 0 54 10 0 12 12 18 41 261 -2 53 28 27 54 52 8 52 36 5 55 46 59 115 0 0 53 38 55 12 12 20 40 262 -3 52 57 18 54 21 8 52 4 50 55 16 6 116 0 0 53 7 20 12 12 23 40 264 -4 52 25 38 53 49 37 51 33 6 54 44 41 117 0 0 52 35 15 12 12 25 39 265 -5 51 53 30 53 17 36 51 0 53 54 12 45 118 0 0 52 2 41 12 12 28 38 266 -5 51 20 52 52 45 5 50 28 12 53 40 18 119 0 0 51 29 38 12 12 30 38 268 -6 50 47 48 52 12 5 49 55 4 53 7 21 120 0 0 50 56 8 12 12 33 37 269 -7 50 14 16 51 38 37 49 21 30 52 33 56 121 0 0 50 22 12 12 12 35 37 270 -8 49 40 19 51 4 42 48 47 32 52 0 3 122 0 0 49 47 50 12 12 38 36 271 -9 49 5 56 50 30 21 48 13 9 51 25 42 123 0 0 49 13 4 12 12 41 35 272 -10 48 31 10 49 55 35 47 38 23 50 50 56 124 0 0 48 37 55 12 12 43 35 273 -11 47 56 1 49 20 24 47 3 15 50 15 45 125 0 0 48 2 23 12 12 45 34 275 -11 47 20 31 48 44 52 46 27 46 49 40 10 126 0 0 47 26 31 12 12 48 33 276 -12 46 44 41 48 8 57 45 51 58 49 4 13 127 0 0 46 50 19 12 12 50 32 277 -13 46 8 31 47 32 43 45 15 51 48 27 55 128 0 0 46 13 48 12 12 53 32 278 -14 45 32 4 46 56 9 44 39 28 47 51 17 129 0 0 45 37 1 12 12 55 31 279 -15 44 55 21 46 19 18 44 2 49 47 14 21 130 0 0 44 59 59 12 12 57 30 280 -16 44 18 23 45 42 12 43 25 56 46 37 8 131 0 0 44 22 43 12 13 0 29 281 -17 43 41 11 45 4 50 42 48 51 45 59 40 132 0 0 43 45 15 12 13 2 28 282 -18 43 3 48 44 27 16 42 11 34 45 21 59 133 0 0 43 7 35 12 13 4 28 283 -19 42 26 15 43 49 31 41 34 8 44 44 5 134 0 0 42 29 47 12 13 6 27 284 -20 41 48 33 43 11 36 40 56 34 44 6 2 135 0 0 41 51 51 12 13 9 26 284 -21 41 10 44 42 33 33 40 18 53 43 27 49 136 0 0 41 13 49 12 13 11 25 285 -22 40 32 49 41 55 24 39 41 8 42 49 29 137 0 0 40 35 43 12 13 13 24 286 -23 39 54 51 41 17 9 39 3 19 42 11 4 138 0 0 39 57 35 12 13 15 23 287 -24 39 16 50 40 38 52 38 25 28 41 32 36 139 0 0 39 19 25 12 13 17 22 288 -25 38 38 49 40 0 34 37 47 38 40 54 5 140 0 0 38 41 16 12 13 18 21 289 -26 38 0 49 39 22 15 37 9 48 40 15 34 141 0 0 38 3 9 12 13 20 20 289 -27 37 22 52 38 43 59 36 32 2 39 37 5 142 0 0 37 25 6 12 13 22 19 290 -28 36 44 58 38 5 46 35 54 21 38 58 39 143 0 0 36 47 9 12 13 23 18 291 -29 36 7 11 37 27 38 35 16 45 38 20 17 144 0 0 36 9 18 12 13 25 17 291 -30 35 29 31 36 49 37 34 39 18 37 42 2 145 0 0 35 31 37 12 13 26 16 292 -31 34 51 59 36 11 45 34 1 59 37 3 55 146 0 0 34 54 5 12 13 28 15 293 -32 34 14 39 35 34 3 33 24 52 36 25 58 147 0 0 34 16 46 12 13 29 14 293 -33 33 37 30 34 56 32 32 47 56 35 48 12 148 0 0 33 39 39 12 13 30 13 294 -34 33 0 34 34 19 14 32 11 14 35 10 39 149 0 0 33 2 47 12 13 32 12 295 -35 32 23 53 33 42 10 31 34 47 34 33 20 150 0 0 32 26 11 12 13 33 11 295 -36 31 47 29 33 5 23 30 58 36 33 56 17 151 0 0 31 49 53 12 13 34 10 296 -37 31 11 21 32 28 52 30 22 42 33 19 31 152 0 0 31 13 53 12 13 34 9 296 -37 30 35 33 31 52 40 29 47 8 32 43 3 153 0 0 30 38 13 12 13 35 8 297 -38 30 0 4 31 16 49 29 11 54 32 6 55 154 0 0 30 2 54 12 13 36 7 297 -39 29 24 57 30 41 18 28 37 0 31 31 9 155 0 0 29 27 57 12 13 36 6 298 -40 28 50 12 30 6 9 28 2 30 30 55 44 156 0 0 28 53 24 12 13 37 5 298 -41 28 15 51 29 31 24 27 28 22 30 20 43 157 0 0 28 19 16 12 13 37 4 299 -42 27 41 54 28 57 4 .. .. .. 29 46 7 158 0 0 27 45 33 12 13 38 3 299 -43 27 8 22 28 23 9 .. .. .. 29 11 57 159 0 0 27 12 17 12 13 38 2 300 -44 26 35 18 27 49 41 .. .. .. 28 38 13 160 0 0 26 39 28 12 13 38 1 300 -45 26 2 40 27 16 41 .. .. .. 28 4 57 Uncertainty in time = +/- 3 secs [Prediction of 2008 Mar 31.0] Data for the target star ------------------------ * name: TYC 1901-01118-1 * constellation : Gemini * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 06 49 07.8999 DE: +27 16 19.420 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .028, .018 ) * V mag [mag]: 11.3 * B mag [mag]: 12.0 * Apparent position with proper motion RA(deg): 102.4126438723 DE(deg): 27.2645709579 * Equation of equinoxes (radians) : 0.000037793885742 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (227) Philosophia approx. diameter [km]: 87 approx. diameter ["]: .032 distance from Earth [AU]: 3.74600 * orbital information: orbit source: Preston date of fit: 2008 Mar 28 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 912 number of rejected observations: 76 time covered by the observations: 1908 Jan 30 - 2008 Mar 10 1 sigma uncertainty ellipse (major, minor, PA): 0.013, 0.010, 103° remarks: * orbital elements for (227) Philosophia : Mean anomaly = 267.12821443 deg Arg. of pericenter = 262.38660411 deg Long. of node = 327.76430932 deg Inclination = 9.14570334 deg Eccentricity = 0.19801418 Semimajor axis = 3.15323186 AU Perihelion dist = 2.52884723 AU Mag: H = 9.01, G = 0.15 Epoch of elements : MJD 54590.50800000 TDT (2008 May 04.508) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 May 4 227 Philosophia 12h 11.0m UT 11.3 6 49 7.900 27 16 19.42TYC 1901-01118-1 12.0 15.0 87 2.9 3.746 2.957 -8.31 56.7774 27.275 -3.56 16.16 12.1836 0.13578 0.64821 16.79480 -3.53884 0.00485 -0.00018 2000 267.0387942008 5 4.00000262.386604327.764309 9.1457030.19801418 3.1532319 2.5288472 8.7 5.00.15 RATE 1.7602330 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.030 0.020 92 1.64 0.020 0 54556.5020080504_1118-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 31, 03:53 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org