IOTA/IOTA-ES occultation update for (2813) Zappala / HIP 108253 event on 2008 Mar 26, 02:31 UT Visible from Africa Summary ------- On 2008 Mar 26 UT, the 33 km diameter asteroid (2813) Zappala will occult a 7.7 mag star in the constellation Aquarius for observers along a path across Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 9.9 mag to 17.6 mag (the magnitude of the asteroid) for at most 0.8 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: . The event at a glimpse ---------------------- * Rank: 20 * date and approx. time of event: 2008 Mar 26, 02:28 - 2008 Mar 26, 02:28 UT * midpoint of event [JD]: 2454551.6049875 * magnitude of target star: 7.7 * magnitude drop [mag]: 9.9 * estimated maximum duration [s]: 0.8 * Moon: 83 % sunlit, 98° distance * Sun: 36° distance * rough path description: Africa The occultation path -------------------- * approximate projected width [km]: 33 * 1 sigma uncertainty interval [path widths]: +/- 3.37 * 1 sigma uncertainty interval [seconds]: +/- 4.4 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .056 +/- .038) * 1 sigma uncertainty ellipse (major, minor, PA): ( .057", .036", 76° ) * approx speed of asteroid's shadow [km/s]: 39.6061 * website for maps: http://lunar-occultations.com/iota/asteroids/astrndx.htm http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 108253 by 2813 Zappala 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 ' " Latitude Latitude Latitude Latitude 19 0 0 -30 4 52 2 28 31 1 89 -31 -30 13 50 -29 55 53 -31 14 22 -28 55 28 20 0 0 -30 4 1 2 28 31 2 89 -31 -30 13 0 -29 55 3 -31 13 32 -28 54 37 21 0 0 -30 2 48 2 28 31 2 88 -30 -30 11 46 -29 53 49 -31 12 20 -28 53 23 22 0 0 -30 1 12 2 28 31 3 88 -29 -30 10 10 -29 52 13 -31 10 44 -28 51 46 23 0 0 -29 59 12 2 28 31 4 87 -28 -30 8 11 -29 50 14 -31 8 46 -28 49 46 24 0 0 -29 56 50 2 28 31 5 87 -27 -30 5 49 -29 47 51 -31 6 25 -28 47 22 25 0 0 -29 54 5 2 28 31 6 86 -26 -30 3 4 -29 45 6 -31 3 42 -28 44 36 26 0 0 -29 50 57 2 28 32 7 86 -26 -29 59 56 -29 41 58 -31 0 36 -28 41 26 27 0 0 -29 47 26 2 28 32 8 85 -25 -29 56 26 -29 38 26 -30 57 7 -28 37 53 28 0 0 -29 43 32 2 28 32 8 85 -24 -29 52 32 -29 34 32 -30 53 15 -28 33 56 29 0 0 -29 39 15 2 28 33 9 84 -23 -29 48 15 -29 30 15 -30 49 0 -28 29 37 30 0 0 -29 34 34 2 28 33 10 84 -22 -29 43 35 -29 25 34 -30 44 23 -28 24 54 31 0 0 -29 29 31 2 28 34 11 83 -21 -29 38 32 -29 20 30 -30 39 22 -28 19 47 32 0 0 -29 24 5 2 28 34 12 83 -20 -29 33 6 -29 15 3 -30 33 59 -28 14 18 33 0 0 -29 18 15 2 28 35 13 82 -20 -29 27 17 -29 9 13 -30 28 13 -28 8 25 34 0 0 -29 12 3 2 28 35 14 82 -19 -29 21 5 -29 3 0 -30 22 4 -28 2 9 35 0 0 -29 5 27 2 28 36 15 81 -18 -29 14 30 -28 56 24 -30 15 32 -27 55 29 36 0 0 -28 58 28 2 28 36 16 81 -17 -29 7 31 -28 49 24 -30 8 37 -27 48 26 37 0 0 -28 51 5 2 28 37 16 80 -16 -29 0 9 -28 42 2 -30 1 19 -27 41 0 38 0 0 -28 43 20 2 28 38 17 80 -15 -28 52 24 -28 34 16 -29 53 37 -27 33 10 39 0 0 -28 35 11 2 28 39 18 79 -14 -28 44 16 -28 26 6 -29 45 33 -27 24 57 40 0 0 -28 26 39 2 28 39 19 79 -14 -28 35 45 -28 17 34 -29 37 6 -27 16 20 41 0 0 -28 17 44 2 28 40 20 78 -13 -28 26 50 -28 8 38 -29 28 16 -27 7 20 42 0 0 -28 8 25 2 28 41 21 78 -12 -28 17 32 -27 59 19 -29 19 2 -26 57 56 43 0 0 -27 58 44 2 28 42 22 77 -11 -28 7 51 -27 49 36 -29 9 26 -26 48 9 44 0 0 -27 48 38 2 28 43 23 77 -10 -27 57 47 -27 39 30 -28 59 26 -26 37 58 45 0 0 -27 38 10 2 28 44 24 76 -9 -27 47 19 -27 29 1 -28 49 3 -26 27 24 46 0 0 -27 27 18 2 28 45 24 76 -8 -27 36 28 -27 18 8 -28 38 17 -26 16 26 47 0 0 -27 16 3 2 28 46 25 75 -7 -27 25 14 -27 6 52 -28 27 8 -26 5 5 48 0 0 -27 4 25 2 28 47 26 75 -7 -27 13 36 -26 55 13 -28 15 36 -25 53 21 49 0 0 -26 52 23 2 28 49 27 75 -6 -27 1 35 -26 43 11 -28 3 41 -25 41 13 50 0 0 -26 39 58 2 28 50 28 74 -5 -26 49 11 -26 30 45 -27 51 22 -25 28 41 51 0 0 -26 27 10 2 28 51 29 74 -4 -26 36 23 -26 17 56 -27 38 40 -25 15 46 52 0 0 -26 13 58 2 28 52 30 73 -3 -26 23 13 -26 4 43 -27 25 36 -25 2 28 53 0 0 -26 0 23 2 28 54 31 73 -2 -26 9 39 -25 51 8 -27 12 8 -24 48 47 54 0 0 -25 46 25 2 28 55 32 72 -1 -25 55 42 -25 37 9 -26 58 17 -24 34 42 55 0 0 -25 32 4 2 28 56 33 72 0 -25 41 22 -25 22 47 -26 44 3 -24 20 14 Uncertainty in time = +/- 5 secs [Prediction of 2008 Feb 14.0] Data for the target star ------------------------ * name: HIP 108253 * constellation : Aquarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 21 55 52.1302 DE: +00 18 00.903 * position source: mpos:HIP pm:HIP plx:HIP * standard error: RA,DE ["]: ( .027, .013 ) * V mag [mag]: 7.7 * B mag [mag]: 7.7 * Apparent position with proper motion RA(deg): 329.0706331769 DE(deg): 0.3369716775 * Equation of equinoxes (radians) : 0.000040617119163 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (2813) Zappala approx. diameter [km]: 33 approx. diameter ["]: .011 distance from Earth [AU]: 4.31300 * orbital information: orbit source: Preston date of fit: 2008 Feb 13 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 491 number of rejected observations: 14 time covered by the observations: 1949 Mar 29 - 2007 Jun 16 1 sigma uncertainty ellipse (major, minor, PA): 0.050, 0.034, 72° remarks: * orbital elements for (2813) Zappala : Mean anomaly = 209.19083674 deg Arg. of pericenter = 247.78516528 deg Long. of node = 231.90597473 deg Inclination = 14.73647686 deg Eccentricity = 0.14837302 Semimajor axis = 3.13823410 AU Perihelion dist = 2.67260483 AU Mag: H = 10.75, G = 0.15 Epoch of elements : MJD 54551.10500000 TDT (2008 Mar 26.105) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Mar 26 2813 Zappala 2h 31.2m UT 7.7 21 55 52.130 0 18 0.90HIP 108253 7.8 17.6 33 0.8 4.313 2.762 18.99 107.2566 0.295 143.63 2.31 2.5197 0.03915 -0.08348 20.32140 9.31540 -0.00347 -0.00020 2000 208.9949352008 325.00000247.785165231.905975 14.7364770.14837302 3.1382341 2.672604811.0 5.00.15 RATE 1.7728670 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.057 0.036 76 4.37 0.036 0 54510.5020080326_108253 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Feb 14, 19:45 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org