IOTA/IOTA-ES occultation update for (128) Nemesis / 2UCAC 23026231 event on 2008 Mar 29, 02:36 UT Visible from Africa Summary ------- On 2008 Mar 29 UT, the 188 km diameter asteroid (128) Nemesis will occult a 12.1 mag star in the constellation Capricornus 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 1.3 mag to 13.0 mag (the magnitude of the asteroid) for at most 6.2 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: 99 * date and approx. time of event: 2008 Mar 29, 02:33 - 2008 Mar 29, 02:34 UT * magnitude of target star: 12.1 * magnitude drop [mag]: 1.3 * estimated maximum duration [s]: 6.2 * Moon: 58 % sunlit, 33° distance * Sun: 66° distance * rough path description: Africa The occultation path -------------------- * approximate projected width [km]: 204 * 1 sigma uncertainty interval [path widths]: +/- 0.28 * 1 sigma uncertainty interval [seconds]: +/- 2.8 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .042 +/- .024) * 1 sigma uncertainty ellipse (major, minor, PA): ( .042", .024", 89° ) * approx speed of asteroid's shadow [km/s]: 30.4001 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 23026231 by 128 Nemesis on 2008 Mar 29 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 - 3 0 0 13 24 49 2 33 4 1 113 -52 12 25 8 14 24 59 11 51 54 14 58 53 - 2 0 0 13 0 30 2 33 4 2 113 -51 12 0 54 14 0 34 11 27 44 14 34 25 - 1 0 0 12 36 25 2 33 4 3 113 -51 11 36 54 13 36 23 11 3 47 14 10 11 0 0 0 12 12 33 2 33 5 4 113 -50 11 13 9 13 12 26 10 40 4 13 46 10 1 0 0 11 48 56 2 33 5 5 114 -49 10 49 37 12 48 43 10 16 36 13 22 24 2 0 0 11 25 35 2 33 5 6 114 -48 10 26 22 12 25 15 9 53 23 12 58 53 3 0 0 11 2 29 2 33 6 7 114 -48 10 3 21 12 2 3 9 30 27 12 35 38 4 0 0 10 39 39 2 33 6 8 114 -47 9 40 38 11 39 8 9 7 46 12 12 39 5 0 0 10 17 6 2 33 7 9 114 -46 9 18 11 11 16 29 8 45 23 11 49 56 6 0 0 9 54 51 2 33 8 10 115 -45 8 56 1 10 54 7 8 23 16 11 27 31 7 0 0 9 32 53 2 33 8 11 115 -44 8 34 10 10 32 3 8 1 28 11 5 23 8 0 0 9 11 13 2 33 9 12 115 -43 8 12 36 10 10 17 7 39 58 10 43 34 9 0 0 8 49 53 2 33 10 13 115 -42 7 51 22 9 48 50 7 18 47 10 22 4 10 0 0 8 28 51 2 33 11 14 115 -42 7 30 27 9 27 43 6 57 55 10 0 52 11 0 0 8 8 10 2 33 12 15 116 -41 7 9 51 9 6 55 6 37 23 9 40 1 12 0 0 7 47 48 2 33 13 16 116 -40 6 49 36 8 46 27 6 17 11 9 19 30 13 0 0 7 27 47 2 33 15 17 116 -39 6 29 41 8 26 20 5 57 20 8 59 19 14 0 0 7 8 7 2 33 16 18 116 -38 6 10 7 8 6 33 5 37 49 8 39 29 15 0 0 6 48 48 2 33 17 19 116 -37 5 50 55 7 47 8 5 18 40 8 20 0 16 0 0 6 29 52 2 33 19 21 116 -36 5 32 4 7 28 5 4 59 53 8 0 53 17 0 0 6 11 17 2 33 20 22 117 -35 5 13 35 7 9 24 4 41 27 7 42 9 18 0 0 5 53 4 2 33 22 23 117 -34 4 55 28 6 51 5 4 23 24 7 23 47 19 0 0 5 35 14 2 33 23 24 117 -33 4 37 45 6 33 10 4 5 43 7 5 47 20 0 0 5 17 48 2 33 25 25 117 -32 4 20 24 6 15 37 3 48 26 6 48 11 21 0 0 5 0 44 2 33 27 26 117 -31 4 3 26 5 58 28 3 31 32 6 30 59 22 0 0 4 44 5 2 33 29 27 118 -30 3 46 53 5 41 42 3 15 1 6 14 10 23 0 0 4 27 49 2 33 30 28 118 -29 3 30 43 5 25 21 2 58 54 5 57 45 24 0 0 4 11 58 2 33 32 29 118 -28 3 14 57 5 9 24 2 43 11 5 41 45 25 0 0 3 56 31 2 33 34 30 118 -27 2 59 36 4 53 51 2 27 53 5 26 9 26 0 0 3 41 29 2 33 37 31 118 -26 2 44 39 4 38 44 2 12 59 5 10 59 27 0 0 3 26 52 2 33 39 32 119 -25 2 30 7 4 24 1 1 58 30 4 56 13 28 0 0 3 12 40 2 33 41 33 119 -24 2 16 0 4 9 44 1 44 26 4 41 53 29 0 0 2 58 53 2 33 43 34 119 -23 2 2 19 3 55 52 1 30 48 4 27 58 30 0 0 2 45 32 2 33 45 35 119 -23 1 49 3 3 42 26 1 17 35 4 14 29 31 0 0 2 32 37 2 33 48 36 120 -22 1 36 12 3 29 26 1 4 47 4 1 26 32 0 0 2 20 8 2 33 50 37 120 -21 1 23 48 3 16 52 0 52 25 3 48 50 33 0 0 2 8 5 2 33 53 38 120 -20 1 11 49 3 4 45 0 40 29 3 36 39 34 0 0 1 56 28 2 33 55 39 120 -19 1 0 17 2 53 3 0 28 59 3 24 56 35 0 0 1 45 18 2 33 58 40 121 -18 0 49 11 2 41 49 0 17 56 3 13 39 36 0 0 1 34 35 2 34 0 41 121 -17 0 38 32 2 31 1 0 7 19 3 2 49 37 0 0 1 24 18 2 34 3 41 121 -16 0 28 19 2 20 40 - 0 2 52 2 52 25 38 0 0 1 14 28 2 34 6 42 122 -15 0 18 33 2 10 47 - 0 12 36 2 42 29 39 0 0 1 5 5 2 34 9 43 122 -14 0 9 14 2 1 20 - 0 21 53 2 33 1 40 0 0 0 56 10 2 34 11 44 123 -13 0 0 22 1 52 21 - 0 30 43 2 23 59 41 0 0 0 47 41 2 34 14 45 123 -12 - 0 8 3 1 43 49 - 0 39 7 2 15 26 42 0 0 0 39 40 2 34 17 46 124 -11 - 0 16 1 1 35 45 - 0 47 3 2 7 19 43 0 0 0 32 6 2 34 20 47 124 -10 - 0 23 32 1 28 8 - 0 54 32 1 59 41 44 0 0 0 25 0 2 34 23 48 125 -9 - 0 30 35 1 20 59 - 1 1 34 1 52 30 45 0 0 0 18 22 2 34 26 49 125 -8 - 0 37 11 1 14 17 - 1 8 8 1 45 47 46 0 0 0 12 11 2 34 29 50 126 -7 - 0 43 20 1 8 4 - 1 14 15 1 39 33 47 0 0 0 6 28 2 34 32 51 126 -6 - 0 49 1 1 2 19 - 1 19 55 1 33 46 48 0 0 0 1 12 2 34 35 51 127 -5 - 0 54 14 0 57 1 - 1 25 7 1 28 27 49 0 0 - 0 3 35 2 34 39 52 128 -4 - 0 58 59 0 52 12 - 1 29 51 1 23 37 50 0 0 - 0 7 55 2 34 42 53 128 -3 - 1 3 17 0 47 51 - 1 34 8 1 19 14 51 0 0 - 0 11 46 2 34 45 54 129 -2 - 1 7 7 0 43 58 - 1 37 57 1 15 21 52 0 0 - 0 15 10 2 34 48 55 130 -1 - 1 10 29 0 40 33 - 1 41 18 1 11 55 Uncertainty in time = +/- 3 secs [Prediction of 2008 Mar 13.0] Data for the target star ------------------------ * name: 2UCAC 23026231 * constellation : Capricornus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 20 23 21.1008 DE: -22 02 45.751 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .041, .023 ) * V mag [mag]: 12.1 * B mag [mag]: 0.0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (128) Nemesis approx. diameter [km]: 188 approx. diameter ["]: .087 distance from Earth [AU]: 2.99400 * orbital information: orbit source: Preston date of fit: 2008 Mar 12 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 673 number of rejected observations: 155 time covered by the observations: 1904 Nov 17 - 2007 Sep 21 1 sigma uncertainty ellipse (major, minor, PA): 0.012, 0.008, 82° remarks: * orbital elements for (128) Nemesis : Mean anomaly = 279.32845393 deg Arg. of pericenter = 302.23040747 deg Long. of node = 76.45369441 deg Inclination = 6.25089767 deg Eccentricity = 0.12546197 Semimajor axis = 2.75240142 AU Perihelion dist = 2.40707972 AU Mag: H = 7.49, G = 0.15 Epoch of elements : MJD 54554.10800000 TDT (2008 Mar 29.108) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Mar 29 128 Nemesis 2h 36.3m UT 12.1 20 23 21.101-22 2 45.752UCAC 23026231 0.0 13.0 188 6.2 2.994 3.586 7.39 79.8907 -22.048 142.13 3.48 2.6048 -0.05624 0.38790 16.97342 2.51470 -0.00506 -0.00132 2000 278.4417742008 325.00000302.230407 76.453694 6.2508980.12546197 2.7524014 2.4070797 7.5 5.00.15 RATE 2.1584220 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.042 0.024 89 1.28 0.025 0 54538.5020080329_026231 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 13, 00:03 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org