IOTA/IOTA-ES occultation update for (85) Io / TYC 0755-01401-1 event on 2005 May 15, 03:50 UT Visible from SW USA Summary ------- On 2005 May 15 UT, the 154 km diameter asteroid (85) Io will occult a 10.6 mag star in the constellation Gemini for observers along a path across SW USA. In the case of an occultation, the combined light of the asteroid and the star will drop by 3.2 mag to 13.7 mag (the magnitude of the asteroid) for at most 4.4 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Ron Stone, 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: 99 * date and approx. time of event: 2005 May 15, 03:54 - 2005 May 15, 03:55 UT * magnitude of target star: 10.6 * magnitude drop [mag]: 3.2 * estimated maximum duration [s]: 4.4 * Moon: 38 % sunlit, 32° distance * Sun: 49° distance * rough path description: SW USA The occultation path -------------------- * approximate projected width [km]: 176 * 1 sigma uncertainty interval [path widths]: +/- 0.33 * 1 sigma uncertainty interval [seconds]: +/- 1.5 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .021 +/- .019) * 1 sigma uncertainty ellipse (major, minor, PA): ( .021", .019", 91° ) * approx speed of asteroid's shadow [km/s]: 34.8068 * website for maps: http://lunar-occultations.com/iota/asteroids/astrndx.htm http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 0755-01401-1 by 85 Io on 2005 May 15 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 37 30 53 3 54 49 35 259 -1 36 42 13 38 19 57 36 10 17 38 52 34 -132 0 0 37 20 42 3 54 50 34 260 -2 36 32 0 38 9 48 36 0 3 38 42 26 -131 0 0 37 10 22 3 54 52 33 261 -3 36 21 38 37 59 30 35 49 40 38 32 9 -130 0 0 36 59 52 3 54 54 33 261 -3 36 11 7 37 49 2 35 39 8 38 21 42 -129 0 0 36 49 14 3 54 55 32 262 -4 36 0 27 37 38 25 35 28 27 38 11 7 -128 0 0 36 38 27 3 54 57 31 263 -5 35 49 38 37 27 40 35 17 37 38 0 23 -127 0 0 36 27 31 3 54 58 30 264 -6 35 38 40 37 16 46 35 6 38 37 49 30 -126 0 0 36 16 27 3 55 0 29 264 -7 35 27 34 37 5 43 34 55 31 37 38 28 -125 0 0 36 5 14 3 55 1 29 265 -7 35 16 20 36 54 32 34 44 16 37 27 18 -124 0 0 35 53 53 3 55 3 28 266 -8 35 4 58 36 43 13 34 32 53 37 16 0 -123 0 0 35 42 24 3 55 4 27 267 -9 34 53 27 36 31 45 34 21 21 37 4 33 -122 0 0 35 30 48 3 55 6 26 267 -10 34 41 49 36 20 10 34 9 42 36 52 59 -121 0 0 35 19 3 3 55 7 25 268 -11 34 30 3 36 8 27 33 57 55 36 41 17 -120 0 0 35 7 11 3 55 8 25 269 -11 34 18 10 35 56 37 33 46 1 36 29 28 -119 0 0 34 55 12 3 55 10 24 269 -12 34 6 10 35 44 39 33 34 0 36 17 31 -118 0 0 34 43 6 3 55 11 23 270 -13 33 54 2 35 32 35 33 21 52 36 5 27 -117 0 0 34 30 53 3 55 12 22 271 -14 33 41 48 35 20 23 33 9 37 35 53 17 -116 0 0 34 18 34 3 55 13 21 271 -15 33 29 27 35 8 5 32 57 15 35 40 59 -115 0 0 34 6 8 3 55 14 21 272 -15 33 17 0 34 55 40 32 44 47 35 28 35 -114 0 0 33 53 35 3 55 15 20 273 -16 33 4 27 34 43 8 32 32 13 35 16 5 -113 0 0 33 40 57 3 55 17 19 273 -17 32 51 47 34 30 31 32 19 33 35 3 28 -112 0 0 33 28 13 3 55 18 18 274 -18 32 39 2 34 17 48 32 6 47 34 50 46 -111 0 0 33 15 23 3 55 19 17 274 -19 32 26 11 34 4 59 31 53 56 34 37 58 -110 0 0 33 2 28 3 55 19 16 275 -19 32 13 16 33 52 5 31 41 0 34 25 4 -109 0 0 32 49 28 3 55 20 15 275 -20 32 0 15 33 39 6 31 27 58 34 12 6 -108 0 0 32 36 23 3 55 21 15 276 -21 31 47 9 33 26 2 31 14 52 33 59 2 -107 0 0 32 23 14 3 55 22 14 277 -22 31 33 59 33 12 53 31 1 41 33 45 54 -106 0 0 32 10 0 3 55 23 13 277 -23 31 20 44 32 59 40 30 48 26 33 32 41 -105 0 0 31 56 42 3 55 23 12 278 -23 31 7 26 32 46 23 30 35 7 33 19 24 -104 0 0 31 43 20 3 55 24 11 278 -24 30 54 3 32 33 1 30 21 45 33 6 3 -103 0 0 31 29 55 3 55 25 10 279 -25 30 40 37 32 19 36 30 8 18 32 52 38 -102 0 0 31 16 26 3 55 25 9 279 -26 30 27 8 32 6 8 29 54 49 32 39 10 -101 0 0 31 2 54 3 55 26 8 280 -26 30 13 36 31 52 36 29 41 17 32 25 39 -100 0 0 30 49 19 3 55 26 8 280 -27 30 0 1 31 39 2 29 27 42 32 12 5 - 99 0 0 30 35 42 3 55 26 7 281 -28 29 46 24 31 25 25 29 14 4 31 58 28 - 98 0 0 30 22 3 3 55 27 6 281 -29 29 32 44 31 11 46 29 0 24 31 44 49 - 97 0 0 30 8 21 3 55 27 5 282 -29 29 19 3 30 58 4 28 46 43 31 31 7 - 96 0 0 29 54 38 3 55 27 4 282 -30 29 5 20 30 44 21 28 33 0 31 17 24 - 95 0 0 29 40 54 3 55 28 3 283 -31 28 51 35 30 30 37 28 19 16 31 3 40 - 94 0 0 29 27 8 3 55 28 2 283 -32 28 37 50 30 16 51 28 5 30 30 49 54 - 93 0 0 29 13 22 3 55 28 1 284 -32 28 24 3 30 3 4 27 51 44 30 36 7 - 92 0 0 28 59 35 3 55 28 0 284 -33 28 10 17 29 49 17 27 37 57 30 22 20 Data for the target star ------------------------ * name: TYC 0755-01401-1 * constellation : Gemini * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 06 52 06.1550 DE: +12 47 05.799 * position source: Pos: UCAC2, pm: UCAC2, pi: * standard error: RA,DE ["]: ( .018, .018 ) * V mag [mag]: 10.6 * B mag [mag]: 12.5 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (85) Io approx. diameter [km]: 154 approx. diameter ["]: .058 distance from Earth [AU]: 3.63700 * orbital information: orbit source: Preston date of fit: 2004 Dec 12 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 921 number of rejected observations: 86 time covered by the observations: 1904 Oct 09 - 2004 Dec 02 1 sigma uncertainty ellipse (major, minor, PA): 0.010, 0.008, 94° remarks: * orbital elements for (85) Io : Mean anomaly = 139.61162972 deg Arg. of pericenter = 122.33859767 deg Long. of node = 203.44261981 deg Inclination = 11.96654539 deg Eccentricity = 0.19288678 Semimajor axis = 2.65247791 AU Perihelion dist = 2.14084999 AU Mag: H = 7.48, G = 0.15 Epoch of elements : MJD 53505.16000000 TDT (2005 May 15.160) ------ occelmnt file for Occult BEGIN ----------------------------------- 2005 May 15 85 Io 3h 52.8m UT 10.6 6 52 6.155 12 47 5.80TYC 0755-01401-1 12.5 13.7 154 4.4 3.637 3.247 0.29 -188.156 12.785 -239.11 18.88 3.8800 -.00341 .48731 19.64555 0.12079 0.00417 -0.00105 2000 138.4343592005 510.00000122.338598203.442620 11.9665450.192886782.652477912.140849997.615 0.1 RATE 2.2815320 .0000000 .0000000 .0000000 .00000000 .00000000 .00000000 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2004 Dec 12, 23:50 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org