IOTA/IOTA-ES occultation update for (1086) Nata / TYC 1856-00744-1 event on 2008 Mar 26, 23:00 UT Visible from Argentina, Chile in twilight Summary ------- On 2008 Mar 26 UT, the 66 km diameter asteroid (1086) Nata will occult a 10.5 mag star in the constellation Taurus for observers along a path across Argentina, Chile in twilight. In the case of an occultation, the combined light of the asteroid and the star will drop by 4.6 mag to 15.1 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: 76 * date and approx. time of event: 2008 Mar 26, 23:01 - 2008 Mar 26, 23:02 UT * midpoint of event [JD]: 2454552.45840417 * magnitude of target star: 10.5 * magnitude drop [mag]: 4.6 * estimated maximum duration [s]: 2.9 * Moon: 77 % sunlit, 160° distance * Sun: 77° distance * rough path description: Argentina, Chile in twilight The occultation path -------------------- * approximate projected width [km]: 146 * 1 sigma uncertainty interval [path widths]: +/- 0.74 * 1 sigma uncertainty interval [seconds]: +/- 2.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .028 +/- .022) * 1 sigma uncertainty ellipse (major, minor, PA): ( .028", .022", 91° ) * approx speed of asteroid's shadow [km/s]: 23.0098 * website for maps: http://lunar-occultations.com/iota/asteroids/astrndx.htm http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 1856-00744-1 by 1086 Nata on 2008 Mar 26 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 - 50 40 13 -56 0 0 23 2 10 1 328 -15 - 52 5 52 - 49 16 13 - 54 16 2 ... .. .. - 51 52 34 -55 0 0 23 2 9 2 329 -15 - 53 17 31 - 50 29 20 - 55 26 45 ... .. .. - 53 6 58 -54 0 0 23 2 9 3 330 -14 - 54 31 25 - 51 44 17 - 56 40 1 ... .. .. - 54 23 33 -53 0 0 23 2 8 5 331 -14 - 55 47 41 - 53 1 14 - 57 55 59 ... .. .. - 55 42 27 -52 0 0 23 2 7 6 332 -13 - 57 6 30 - 54 20 19 - 59 14 50 ... .. .. - 57 3 53 -51 0 0 23 2 5 7 333 -13 - 58 28 4 - 55 41 44 - 60 36 48 - 53 43 27 - 58 28 5 -50 0 0 23 2 3 9 334 -12 - 59 52 37 - 57 5 41 - 62 2 10 - 55 7 13 - 59 55 18 -49 0 0 23 2 1 10 336 -11 - 61 20 29 - 58 32 24 - 63 31 17 - 56 33 26 - 61 25 51 -48 0 0 23 1 58 11 337 -10 - 62 51 58 - 60 2 12 - 65 4 34 - 58 2 22 - 63 0 9 -47 0 0 23 1 55 13 338 -10 - 64 27 33 - 61 35 25 - 66 42 32 - 59 34 20 - 64 38 39 -46 0 0 23 1 51 14 340 -8 - 66 7 45 - 63 12 29 - 68 25 53 - 61 9 42 - 66 21 56 -45 0 0 23 1 47 15 341 -7 - 67 53 15 - 64 53 55 - 70 15 27 - 62 48 53 - 68 10 46 -44 0 0 23 1 42 17 343 -6 - 69 44 55 - 66 40 22 - 72 12 23 - 64 32 25 - 70 6 7 -43 0 0 23 1 36 18 344 -5 - 71 43 55 - 68 32 38 - 74 18 17 - 66 20 58 - 72 9 14 -42 0 0 23 1 30 19 346 -3 - 73 51 49 - 70 31 48 - 76 35 21 - 68 15 24 Latitude Latitude Latitude Latitude - 74 0 0 -41 9 35 23 1 24 20 348 -2 -41 56 19 -40 24 16 -43 8 25 -39 19 31 - 75 0 0 -40 43 41 23 1 21 21 349 -1 -41 29 54 -39 58 49 -42 41 9 -38 54 42 - 76 0 0 -40 18 45 23 1 17 22 350 0 -41 4 30 -39 34 20 -42 14 57 -38 30 48 Uncertainty in time = +/- 3 secs [Prediction of 2008 Feb 14.0] Data for the target star ------------------------ * name: TYC 1856-00744-1 * constellation : Taurus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 05 31 50.3104 DE: +27 28 55.790 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .023, .019 ) * V mag [mag]: 10.5 * B mag [mag]: 11.2 * Apparent position with proper motion RA(deg): 83.0901689340 DE(deg): 27.4904286521 * Equation of equinoxes (radians) : 0.000040643427089 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1086) Nata approx. diameter [km]: 66 approx. diameter ["]: .030 distance from Earth [AU]: 3.04900 * orbital information: orbit source: Preston date of fit: 2008 Feb 13 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 820 number of rejected observations: 64 time covered by the observations: 1900 Dec 21 - 2008 Feb 07 1 sigma uncertainty ellipse (major, minor, PA): 0.016, 0.012, 94° remarks: * orbital elements for (1086) Nata : Mean anomaly = 346.27057482 deg Arg. of pericenter = 164.45182827 deg Long. of node = 313.41293922 deg Inclination = 8.34722253 deg Eccentricity = 0.05579726 Semimajor axis = 3.16295892 AU Perihelion dist = 2.98647448 AU Mag: H = 9.41, G = 0.15 Epoch of elements : MJD 54551.95800000 TDT (2008 Mar 26.958) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Mar 26 1086 Nata 23h 0.1m UT 10.5 5 31 50.310 27 28 55.79TYC 1856-00744-1 11.2 15.1 66 2.9 3.049 2.793 -4.58 -86.8226 27.483 -163.66 2.65 23.0017 -0.10916 -0.88549 12.88988 -1.58844 0.00566 0.00037 2000 345.9275102008 325.00000164.451828313.412939 8.3472230.05579726 3.1629589 2.9864745 9.3 5.00.15 RATE 1.7521200 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.028 0.022 91 1.74 0.022 0 54510.5020080326_0744-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Feb 14, 19:49 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org