IOTA/IOTA-ES occultation update for (230) Athamantis / TYC 6780-01101-1 event on 2010 Feb 20, 13:45 UT Visible from W USA Summary ------- On 2010 Feb 20 UT, the 109 km diameter asteroid (230) Athamantis will occult a 12.6 mag star in the constellation Scorpius for observers along a path across W USA. In the case of an occultation, the combined light of the asteroid and the star will drop by 0.6 mag to 12.2 mag (the magnitude of the asteroid) for at most 5.7 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: 87 * date and approx. time of event: 2010 Feb 20, 13:43 - 2010 Feb 20, 13:45 UT * magnitude of target star: 12.6 * magnitude drop [mag]: 0.6 * estimated maximum duration [s]: 5.7 * Moon: 35 % sunlit, 158° distance * Sun: 86° distance * rough path description: W USA The occultation path -------------------- * approximate projected width [km]: 245 * 1 sigma uncertainty interval [path widths]: +/- 0.57 * 1 sigma uncertainty interval [seconds]: +/- 3.1 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .037 +/- .036) * 1 sigma uncertainty ellipse (major, minor, PA): ( .037", .036", 90° ) * approx speed of asteroid's shadow [km/s]: 18.9816 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6780-01101-1 by 230 Athamantis on 2010 Feb 20 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 -154 24 32 58 0 0 13 43 3 1 143 -31 -157 1 47 -151 42 3 ... .. .. -148 29 8 -152 53 8 57 0 0 13 43 3 2 144 -30 -155 28 56 -150 11 53 ... .. .. -147 0 2 -151 19 50 56 0 0 13 43 4 4 146 -30 -153 54 34 -148 39 22 ... .. .. -145 28 1 -149 44 22 55 0 0 13 43 6 5 147 -30 -152 18 28 -147 4 14 ... .. .. -143 52 47 -148 6 29 54 0 0 13 43 7 6 148 -29 -150 40 23 -145 26 12 ... .. .. -142 13 59 -146 25 52 53 0 0 13 43 10 8 150 -29 -149 0 1 -143 44 53 ... .. .. -140 31 11 -144 42 9 52 0 0 13 43 12 9 151 -28 -147 17 3 -141 59 53 -150 6 11 -138 43 50 -142 54 54 51 0 0 13 43 16 11 153 -27 -145 31 6 -140 10 41 -148 21 8 -136 51 17 -141 3 36 50 0 0 13 43 20 12 154 -27 -143 41 45 -138 16 37 -146 33 17 -134 52 40 -139 7 38 49 0 0 13 43 24 13 156 -26 -141 48 29 -136 16 55 -144 42 11 -132 46 53 -137 6 10 48 0 0 13 43 30 15 158 -24 -139 50 38 -134 10 32 -142 47 19 -130 32 26 Latitude Latitude Latitude Latitude -137 0 0 47 57 2 13 43 30 15 158 -24 46 37 40 49 21 14 45 12 5 51 4 33 -136 0 0 47 28 33 13 43 33 16 159 -24 46 10 1 48 51 46 44 45 15 50 33 39 -135 0 0 47 0 49 13 43 36 16 160 -23 45 43 5 48 23 4 44 19 5 50 3 37 -134 0 0 46 33 48 13 43 39 17 160 -23 45 16 50 47 55 9 43 53 35 49 34 25 -133 0 0 46 7 32 13 43 42 18 161 -22 44 51 19 47 28 2 43 28 47 49 6 5 -132 0 0 45 42 2 13 43 46 18 162 -21 44 26 30 47 1 41 43 4 39 48 38 35 -131 0 0 45 17 16 13 43 49 19 163 -21 44 2 25 46 36 9 42 41 14 48 11 57 -130 0 0 44 53 17 13 43 53 19 164 -20 43 39 4 46 11 24 42 18 31 47 46 10 -129 0 0 44 30 3 13 43 56 20 165 -19 43 16 27 45 47 27 41 56 30 47 21 14 -128 0 0 44 7 36 13 44 0 21 166 -19 42 54 35 45 24 19 41 35 13 46 57 10 -127 0 0 43 45 55 13 44 4 21 167 -18 42 33 28 45 1 59 41 14 38 46 33 57 -126 0 0 43 25 1 13 44 8 22 168 -17 42 13 5 44 40 28 40 54 48 46 11 35 -125 0 0 43 4 53 13 44 12 22 169 -16 41 53 29 44 19 45 40 35 41 45 50 5 -124 0 0 42 45 33 13 44 16 22 170 -16 41 34 37 43 59 51 40 17 19 45 29 26 -123 0 0 42 27 0 13 44 20 23 171 -15 41 16 32 43 40 47 39 59 41 45 9 39 -122 0 0 42 9 15 13 44 24 23 172 -14 40 59 12 43 22 31 39 42 48 44 50 43 -121 0 0 41 52 17 13 44 29 24 173 -13 40 42 39 43 5 5 39 26 39 44 32 39 -120 0 0 41 36 6 13 44 33 24 174 -13 40 26 52 42 48 28 39 11 16 44 15 26 -119 0 0 41 20 44 13 44 37 24 175 -12 40 11 52 42 32 41 38 56 38 43 59 5 -118 0 0 41 6 10 13 44 42 25 176 -11 39 57 39 42 17 43 38 42 45 43 43 36 -117 0 0 40 52 23 13 44 46 25 177 -10 39 44 12 42 3 34 38 29 38 43 28 58 -116 0 0 40 39 25 13 44 51 25 178 -9 39 31 32 41 50 15 38 17 16 43 15 11 -115 0 0 40 27 15 13 44 55 25 179 -9 39 19 39 41 37 46 38 5 40 43 2 16 -114 0 0 40 15 54 13 45 0 26 180 -8 39 8 33 41 26 7 37 54 50 42 50 13 -113 0 0 40 5 20 13 45 4 26 181 -7 38 58 14 41 15 17 37 44 46 42 39 1 -112 0 0 39 55 36 13 45 9 26 182 -6 38 48 43 41 5 17 37 35 29 42 28 41 -111 0 0 39 46 39 13 45 14 26 183 -5 38 39 59 40 56 6 37 26 57 42 19 12 -110 0 0 39 38 31 13 45 18 26 184 -5 38 32 2 40 47 46 37 19 11 42 10 35 -109 0 0 39 31 12 13 45 23 26 185 -4 38 24 53 40 40 15 37 12 12 42 2 50 -108 0 0 39 24 41 13 45 28 26 186 -3 38 18 31 40 33 34 37 5 59 41 55 56 -107 0 0 39 18 59 13 45 32 26 187 -2 38 12 57 40 27 43 37 0 33 41 49 53 -106 0 0 39 14 5 13 45 37 26 188 -1 38 8 10 40 22 42 36 55 53 41 44 42 -105 0 0 39 10 0 13 45 42 26 189 -1 38 4 10 40 18 31 36 51 59 41 40 22 Uncertainty in time = +/- 3 secs Prediction of 2010 Feb 19.0 Data for the target star ------------------------ * name: TYC 6780-01101-1 * constellation : Scorpius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 16 10 49.0140 DE: -24 12 30.899 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .036, .035 ) * V mag [mag]: 12.6 * B mag [mag]: 13.8 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (230) Athamantis approx. diameter [km]: 109 approx. diameter ["]: .063 distance from Earth [AU]: 2.37700 * orbital information: orbit source: Preston date of fit: 2010 Feb 18 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1324 number of rejected observations: 161 time covered by the observations: 1901 Dec 04 - 2010 Jan 18 1 sigma uncertainty ellipse (major, minor, PA): 0.009, 0.007, 88° remarks: * orbital elements for (230) Athamantis : Mean anomaly = 204.55995864 deg Arg. of pericenter = 140.12784085 deg Long. of node = 239.94010857 deg Inclination = 9.43846282 deg Eccentricity = 0.06148765 Semimajor axis = 2.38208295 AU Perihelion dist = 2.23561427 AU Mag: H = 7.39, G = 0.27 Epoch of elements : MJD 55247.57300000 TDT (2010 Feb 20.573) ------ occelmnt file for Occult BEGIN ----------------------------------- 2010 Feb 20 230 Athamantis 13h 45.5m UT 12.6 16 10 49.014-24 12 30.90TYC 6780-01101-1 13.8 12.2 109 5.7 2.377 2.883 -3.91 -114.0586 -24.207 -22.94 -10.83 13.7582 0.08488 0.89119 10.66144 -1.05726 -0.00569 0.00104 2000 202.5297692010 213.00000140.127841239.940109 9.4384630.06148765 2.3820830 2.2356143 7.4 5.00.27 RATE 2.6808270 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.037 0.036 90 1.57 0.036 0 055246.0020100220_1101-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2010 Feb 18, 20:54 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org