IOTA/IOTA-ES occultation update for (497) Iva / TYC 6851-05092-1 event on 2012 Oct 06, 23:48 UT Visible from SE USA Summary ------- On 2012 Oct 06 UT, the 37 km diameter asteroid (497) Iva will occult a 11.4 mag star in the constellation Sagittarius for observers along a path across SE USA. In the case of an occultation, the combined light of the asteroid and the star will drop by 3.6 mag to 15.0 mag (the magnitude of the asteroid) for at most 1.6 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: 20 * date and approx. time of event: 2012 Oct 06, 23:49 - 2012 Oct 06, 23:51 UT * geocentric midpoint of event [JD]: 2456207.49211667 * magnitude of target star: 11.4 * magnitude drop [mag]: 3.6 * estimated maximum duration [s]: 1.6 * Moon: 63 % sunlit, 172° distance * Sun: 80° distance * rough path description: SE USA The occultation path -------------------- * approximate projected width [km]: 60 * 1 sigma uncertainty interval [path widths]: +/- 3.45 * 1 sigma uncertainty interval [seconds]: +/- 6.5 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .095 +/- .076) * 1 sigma uncertainty ellipse (major, minor, PA): ( .095", .076", 90° ) * approx speed of asteroid's shadow [km/s]: 22.1331 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6851-05092-1 by 497 Iva on 2012 Oct 6 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 - 48 42 16 50 0 0 23 51 34 0 223 -30 ... .. .. - 49 16 57 ... .. .. - 53 20 44 - 50 9 56 49 0 0 23 51 33 1 222 -30 - 49 35 43 - 50 44 18 ... .. .. - 54 46 5 - 51 37 54 48 0 0 23 51 33 3 221 -30 - 51 3 59 - 52 12 0 ... .. .. - 56 12 10 - 53 6 21 47 0 0 23 51 32 4 220 -29 - 52 32 38 - 53 40 13 ... .. .. - 57 39 11 - 54 35 24 46 0 0 23 51 31 6 219 -29 - 54 1 52 - 55 9 8 ... .. .. - 59 7 18 - 56 5 16 45 0 0 23 51 30 7 218 -28 - 55 31 50 - 56 38 54 ... .. .. - 60 36 41 - 57 36 6 44 0 0 23 51 28 9 217 -27 - 57 2 44 - 58 9 41 ... .. .. - 62 7 33 - 59 8 6 43 0 0 23 51 26 10 216 -27 - 58 34 43 - 59 41 43 ... .. .. - 63 40 6 - 60 41 28 42 0 0 23 51 24 12 215 -26 - 60 8 1 - 61 15 10 - 56 22 51 - 65 14 35 - 62 16 26 41 0 0 23 51 21 13 213 -25 - 61 42 50 - 62 50 16 - 57 57 7 - 66 51 17 - 63 53 13 40 0 0 23 51 18 15 212 -24 - 63 19 24 - 64 27 17 - 59 32 40 - 68 30 28 - 65 32 6 39 0 0 23 51 15 16 211 -23 - 64 58 0 - 66 6 29 - 61 9 46 - 70 12 32 - 67 13 23 38 0 0 23 51 11 18 210 -22 - 66 38 54 - 67 48 11 - 62 48 37 - 71 57 52 - 68 57 26 37 0 0 23 51 6 19 208 -21 - 68 22 28 - 69 32 44 - 64 29 31 - 73 46 59 - 70 44 39 36 0 0 23 51 1 21 207 -19 - 70 9 5 - 71 20 36 - 66 12 47 - 75 40 28 - 72 35 31 35 0 0 23 50 56 22 206 -18 - 71 59 12 - 73 12 16 - 67 58 45 - 77 39 4 - 74 30 38 34 0 0 23 50 50 24 204 -17 - 73 53 24 - 75 8 21 - 69 47 50 - 79 43 43 - 76 30 43 33 0 0 23 50 43 25 202 -15 - 75 52 21 - 77 9 37 - 71 40 31 - 81 55 39 Latitude Latitude Latitude Latitude - 78 0 0 32 17 9 23 50 38 27 201 -14 31 58 33 32 35 54 29 53 57 34 49 42 - 79 0 0 31 49 13 23 50 34 27 200 -13 31 30 45 32 7 51 29 26 55 34 20 41 - 80 0 0 31 22 0 23 50 31 28 199 -12 31 3 38 31 40 30 29 0 34 33 52 24 - 81 0 0 30 55 29 23 50 27 29 198 -11 30 37 14 31 13 52 28 34 55 33 24 52 - 82 0 0 30 29 42 23 50 23 29 198 -10 30 11 34 30 47 58 28 9 57 32 58 5 - 83 0 0 30 4 38 23 50 19 30 197 -9 29 46 37 30 22 47 27 45 41 32 32 4 - 84 0 0 29 40 19 23 50 15 31 196 -8 29 22 24 29 58 22 27 22 8 32 6 49 - 85 0 0 29 16 44 23 50 11 31 195 -8 28 58 55 29 34 40 26 59 18 31 42 21 - 86 0 0 28 53 53 23 50 7 32 194 -7 28 36 10 29 11 44 26 37 11 31 18 39 - 87 0 0 28 31 48 23 50 2 32 193 -6 28 14 11 28 49 33 26 15 47 30 55 45 - 88 0 0 28 10 29 23 49 58 33 192 -5 27 52 57 28 28 8 25 55 8 30 33 38 - 89 0 0 27 49 55 23 49 54 34 191 -4 27 32 28 28 7 29 25 35 12 30 12 18 - 90 0 0 27 30 7 23 49 49 34 190 -3 27 12 45 27 47 36 25 16 2 29 51 47 - 91 0 0 27 11 5 23 49 45 34 189 -2 26 53 48 27 28 29 24 57 35 29 32 3 - 92 0 0 26 52 50 23 49 40 35 188 -1 26 35 37 27 10 9 24 39 54 29 13 7 - 93 0 0 26 35 21 23 49 36 35 187 0 26 18 13 26 52 35 24 22 57 28 55 0 Uncertainty in time = +/- 7 secs Prediction of 2012 Aug 26.0 Data for the target star ------------------------ * name: TYC 6851-05092-1 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 16 31.8264 DE: -27 55 33.921 * position source: mpos:UCAC4 pm:UCAC4 * standard error: RA,DE ["]: ( .093, .075 ) * V mag [mag]: 11.4 * B mag [mag]: 12.1 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (497) Iva approx. diameter [km]: 37 approx. diameter ["]: .022 distance from Earth [AU]: 2.35300 * orbital information: orbit source: Preston date of fit: 2012 Aug 25 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1172 number of rejected observations: 88 time covered by the observations: 1902 Nov 04 - 2012 Aug 18 1 sigma uncertainty ellipse (major, minor, PA): 0.020, 0.012, 88° remarks: * orbital elements for (497) Iva : Mean anomaly = 317.79098048 deg Arg. of pericenter = 3.43190992 deg Long. of node = 6.51181558 deg Inclination = 4.80842029 deg Eccentricity = 0.29570101 Semimajor axis = 2.85616131 AU Perihelion dist = 2.01159154 AU Mag: H = 9.81, G = 0.11 Epoch of elements : MJD 56206.99200000 TDT (2012 Oct 06.992) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Oct 6 497 Iva 23h 48.6m UT 11.4 18 16 31.826-27 55 33.92TYC 6851-05092-1 12.1 15.0 37 1.6 2.353 3.492 6.20 -99.0668 -27.927 179.80 -5.57 23.8108 -0.10123 0.78344 12.38200 1.65807 0.00550 0.00008 2000 316.3632982012 930.00000 3.431910 6.511816 4.8084200.29570101 2.8561613 2.011591510.0 5.00.11 RATE 2.0418790 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.095 0.076 90 4.45 0.075 0 0 4-1 056165.0020121006_5092-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Aug 25, 23:25 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org