IOTA/IOTA-ES occultation update for (20) Massalia / 2UCAC 23500576 event on 2012 Nov 02, 09:34 UT Visible from Russia Summary ------- On 2012 Nov 02 UT, the 132 km diameter asteroid (20) Massalia will occult a 12.3 mag star in the constellation Sagittarius for observers along a path across Russia. In the case of an occultation, the combined light of the asteroid and the star will drop by 0.6 mag to 11.9 mag (the magnitude of the asteroid) for at most 4.9 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: 70 * date and approx. time of event: 2012 Nov 02, 09:34 - 2012 Nov 02, 09:36 UT * geocentric midpoint of event [JD]: 2456233.89869167 * magnitude of target star: 12.3 * magnitude drop [mag]: 0.6 * estimated maximum duration [s]: 4.9 * Moon: 89 % sunlit, 150° distance * Sun: 69° distance * rough path description: Russia The occultation path -------------------- * approximate projected width [km]: 230 * 1 sigma uncertainty interval [path widths]: +/- 0.83 * 1 sigma uncertainty interval [seconds]: +/- 2.9 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .040 +/- .053) * 1 sigma uncertainty ellipse (major, minor, PA): ( .053", .040", 360° ) * approx speed of asteroid's shadow [km/s]: 26.7982 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 23500576 by 20 Massalia on 2012 Nov 2 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 157 36 56 55 0 0 9 36 22 1 228 -32 160 23 33 154 47 48 ... .. .. 149 59 55 155 33 26 54 0 0 9 36 22 3 227 -32 158 17 46 152 46 19 ... .. .. 148 1 10 Latitude Latitude Latitude Latitude 154 0 0 53 14 28 9 36 21 4 225 -31 51 55 59 54 36 24 .. .. .. 57 1 40 153 0 0 52 45 12 9 36 21 5 225 -31 51 27 3 54 6 46 .. .. .. 56 31 16 152 0 0 52 15 56 9 36 20 6 224 -30 50 58 7 53 37 7 .. .. .. 56 0 51 151 0 0 51 46 41 9 36 20 6 223 -30 50 29 12 53 7 29 48 26 50 55 30 26 150 0 0 51 17 29 9 36 19 7 222 -29 50 0 21 52 37 53 47 58 29 55 0 2 149 0 0 50 48 20 9 36 18 8 221 -29 49 31 34 52 8 21 47 30 11 54 29 42 148 0 0 50 19 17 9 36 17 9 221 -28 49 2 51 51 38 53 47 2 0 53 59 25 147 0 0 49 50 19 9 36 17 9 220 -27 48 34 16 51 9 31 46 33 55 53 29 14 146 0 0 49 21 29 9 36 16 10 219 -27 48 5 47 50 40 16 46 5 58 52 59 9 145 0 0 48 52 47 9 36 14 11 218 -26 47 37 27 50 11 9 45 38 9 52 29 13 144 0 0 48 24 14 9 36 13 12 217 -26 47 9 17 49 42 12 45 10 31 51 59 25 143 0 0 47 55 52 9 36 12 13 217 -25 46 41 17 49 13 25 44 43 3 51 29 48 142 0 0 47 27 42 9 36 11 13 216 -24 46 13 29 48 44 49 44 15 47 51 0 23 141 0 0 46 59 44 9 36 9 14 215 -24 45 45 54 48 16 26 43 48 44 50 31 11 140 0 0 46 32 1 9 36 8 15 214 -23 45 18 32 47 48 17 43 21 55 50 2 13 139 0 0 46 4 31 9 36 6 16 213 -22 44 51 25 47 20 23 42 55 20 49 33 30 138 0 0 45 37 18 9 36 4 16 213 -22 44 24 34 46 52 45 42 29 1 49 5 3 137 0 0 45 10 22 9 36 3 17 212 -21 43 57 59 46 25 24 42 2 59 48 36 53 136 0 0 44 43 43 9 36 1 18 211 -20 43 31 42 45 58 21 41 37 14 48 9 2 135 0 0 44 17 22 9 35 59 19 210 -20 43 5 44 45 31 36 41 11 47 47 41 30 134 0 0 43 51 22 9 35 57 19 209 -19 42 40 5 45 5 12 40 46 39 47 14 19 133 0 0 43 25 42 9 35 55 20 208 -18 42 14 46 44 39 8 40 21 51 46 47 29 132 0 0 43 0 23 9 35 53 21 207 -17 41 49 48 44 13 25 39 57 24 46 21 1 131 0 0 42 35 26 9 35 50 22 207 -17 41 25 12 43 48 5 39 33 19 45 54 56 130 0 0 42 10 52 9 35 48 22 206 -16 41 0 59 43 23 8 39 9 36 45 29 15 129 0 0 41 46 41 9 35 46 23 205 -15 40 37 9 42 58 36 38 46 15 45 3 59 128 0 0 41 22 55 9 35 43 24 204 -14 40 13 43 42 34 28 38 23 19 44 39 8 127 0 0 40 59 35 9 35 41 24 203 -13 39 50 41 42 10 45 38 0 47 44 14 44 126 0 0 40 36 40 9 35 38 25 202 -13 39 28 6 41 47 29 37 38 39 43 50 47 125 0 0 40 14 11 9 35 36 26 201 -12 39 5 56 41 24 39 37 16 58 43 27 17 124 0 0 39 52 10 9 35 33 26 200 -11 38 44 13 41 2 18 36 55 42 43 4 16 123 0 0 39 30 36 9 35 30 27 199 -10 38 22 58 40 40 24 36 34 54 42 41 44 122 0 0 39 9 31 9 35 27 27 198 -9 38 2 10 40 18 59 36 14 32 42 19 42 121 0 0 38 48 54 9 35 24 28 197 -8 37 41 51 39 58 3 35 54 39 41 58 10 120 0 0 38 28 47 9 35 21 28 196 -8 37 22 1 39 37 38 35 35 14 41 37 9 119 0 0 38 9 10 9 35 18 29 195 -7 37 2 40 39 17 42 35 16 18 41 16 39 118 0 0 37 50 3 9 35 15 30 194 -6 36 43 50 38 58 18 34 57 51 40 56 41 117 0 0 37 31 27 9 35 12 30 193 -5 36 25 30 38 39 25 34 39 55 40 37 15 116 0 0 37 13 23 9 35 9 31 192 -4 36 7 40 38 21 4 34 22 28 40 18 23 115 0 0 36 55 50 9 35 6 31 191 -3 35 50 22 38 3 15 34 5 32 40 0 3 114 0 0 36 38 49 9 35 3 31 190 -2 35 33 36 37 45 58 33 49 7 39 42 17 113 0 0 36 22 21 9 34 59 32 189 -2 35 17 22 37 29 15 33 33 13 39 25 5 112 0 0 36 6 26 9 34 56 32 188 -1 35 1 40 37 13 5 33 17 52 39 8 28 Uncertainty in time = +/- 4 secs Prediction of 2012 Oct 26.0 Data for the target star ------------------------ * name: 2UCAC 23500576 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 19 21 18.5584 DE: -21 28 28.227 * position source: mpos:UCAC4 pm:UCAC4 * standard error: RA,DE ["]: ( .039, .052 ) * V mag [mag]: 12.3 * B mag [mag]: 0.0 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (20) Massalia approx. diameter [km]: 132 approx. diameter ["]: .063 distance from Earth [AU]: 2.90500 * orbital information: orbit source: Preston date of fit: 2012 Oct 25 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 1545 number of rejected observations: 254 time covered by the observations: 1900 Jul 17 - 2012 Oct 14 1 sigma uncertainty ellipse (major, minor, PA): 0.006, 0.005, 82° remarks: * orbital elements for (20) Massalia : Mean anomaly = 213.74174268 deg Arg. of pericenter = 256.76033402 deg Long. of node = 206.19581663 deg Inclination = 0.70819072 deg Eccentricity = 0.14248711 Semimajor axis = 2.40881276 AU Perihelion dist = 2.06558800 AU Mag: H = 6.49, G = 0.25 Epoch of elements : MJD 56233.39900000 TDT (2012 Nov 02.399) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Nov 2 20 Massalia 9h 34.1m UT 12.3 19 21 18.558-21 28 28.232UCAC 23500576 0.0 11.9 132 4.9 2.905 3.254 5.83 104.7342 -21.475 32.37 -14.93 9.5686 -0.10234 0.81255 15.00265 1.92506 0.00535 0.00077 2000 212.84565520121030.00000256.760334206.195817 0.7081910.14248711 2.4088128 2.0655880 6.5 5.00.25 RATE 2.6363280 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.053 0.040 360 1.83 0.052 0 0 4 3 056226.0020121102_500576 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Oct 25, 21:42 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org