IOTA/IOTA-ES occultation update for (128) Nemesis / HIP 102498 event on 2008 Oct 01, 14:11 UT Visible from India, China, Russia Summary ------- On 2008 Oct 01 UT, the 188 km diameter asteroid (128) Nemesis will occult a 9.0 mag star in the constellation Capricornus for observers along a path across India, China, Russia. In the case of an occultation, the combined light of the asteroid and the star will drop by 3.0 mag to 11.9 mag (the magnitude of the asteroid) for at most 42.7 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, Hipparcos . The event at a glimpse ---------------------- * Rank: 100 * date and approx. time of event: 2008 Oct 01, 14:06 - 2008 Oct 01, 14:31 UT * magnitude of target star: 9.0 * magnitude drop [mag]: 3.0 * estimated maximum duration [s]: 42.7 * Moon: 5 % sunlit, 91° distance * Sun: 118° distance * rough path description: India, China, Russia Additional comments ------------------- HIP vs UCAC2 pos difference The occultation path -------------------- * approximate projected width [km]: 228 * 1 sigma uncertainty interval [path widths]: +/- 0.16 * 1 sigma uncertainty interval [seconds]: +/- 6.5 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .023 +/- .021) * 1 sigma uncertainty ellipse (major, minor, PA): ( .023", .021", 87° ) * approx speed of asteroid's shadow [km/s]: 4.3943 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 102498 by 128 Nemesis on 2008 Oct 1 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 111 30 43 61 0 0 14 31 15 0 205 -29 ... .. .. 109 14 24 ... .. .. 108 30 49 110 33 53 60 0 0 14 31 15 1 204 -29 112 46 9 108 21 54 113 28 34 107 39 41 109 39 0 59 0 0 14 31 14 2 204 -30 111 47 11 107 31 2 112 28 16 106 50 5 108 45 55 58 0 0 14 31 12 3 203 -30 110 50 17 106 41 39 111 30 8 106 1 53 107 54 25 57 0 0 14 31 10 4 202 -31 109 55 16 105 53 36 110 33 58 105 14 56 107 4 21 56 0 0 14 31 7 6 201 -31 109 1 56 105 6 46 109 39 35 104 29 6 106 15 36 55 0 0 14 31 4 7 201 -32 108 10 8 104 21 0 108 46 48 103 44 17 105 28 2 54 0 0 14 31 0 8 200 -32 107 19 44 103 36 13 107 55 28 103 0 24 104 41 32 53 0 0 14 30 55 9 199 -33 106 30 34 102 52 20 107 5 27 102 17 20 103 56 1 52 0 0 14 30 49 10 199 -33 105 42 34 102 9 15 106 16 38 101 35 2 103 11 22 51 0 0 14 30 43 11 198 -34 104 55 36 101 26 53 105 28 55 100 53 24 102 27 31 50 0 0 14 30 36 12 198 -34 104 9 35 100 45 11 104 42 12 100 12 22 101 44 24 49 0 0 14 30 29 13 197 -34 103 24 25 100 4 4 103 56 22 99 31 54 101 1 56 48 0 0 14 30 21 14 196 -35 102 40 2 99 23 30 103 11 22 98 51 55 100 20 3 47 0 0 14 30 12 15 196 -35 101 56 22 98 43 23 102 27 7 98 12 22 99 38 42 46 0 0 14 30 3 17 195 -35 101 13 20 98 3 42 101 43 33 97 33 12 98 57 50 45 0 0 14 29 53 18 195 -35 100 30 53 97 24 24 101 0 35 96 54 24 98 17 23 44 0 0 14 29 42 19 194 -35 99 48 57 96 45 25 100 18 10 96 15 53 97 37 19 43 0 0 14 29 31 20 193 -36 99 7 29 96 6 43 99 36 15 95 37 37 96 57 35 42 0 0 14 29 19 21 193 -36 98 26 26 95 28 16 98 54 47 94 59 35 96 18 8 41 0 0 14 29 6 22 192 -36 97 45 46 94 50 1 98 13 43 94 21 43 95 38 55 40 0 0 14 28 53 23 192 -36 97 5 24 94 11 57 97 32 59 93 44 0 94 59 55 39 0 0 14 28 39 24 191 -36 96 25 19 93 34 0 96 52 33 93 6 23 94 21 5 38 0 0 14 28 24 25 190 -36 95 45 29 92 56 9 96 12 23 92 28 50 93 42 22 37 0 0 14 28 9 26 190 -36 95 5 50 92 18 21 95 32 26 91 51 20 93 3 45 36 0 0 14 27 53 27 189 -36 94 26 20 91 40 35 94 52 40 91 13 50 92 25 11 35 0 0 14 27 36 28 188 -36 93 46 58 91 2 48 94 13 1 90 36 19 91 46 38 34 0 0 14 27 19 30 188 -35 93 7 40 90 24 59 93 33 29 89 58 44 91 8 4 33 0 0 14 27 1 31 187 -35 92 28 25 89 47 6 92 54 0 89 21 3 90 29 28 32 0 0 14 26 43 32 186 -35 91 49 10 89 9 6 92 14 33 88 43 14 89 50 46 31 0 0 14 26 24 33 186 -35 91 9 54 88 30 58 91 35 5 88 5 16 89 11 57 30 0 0 14 26 4 34 185 -35 90 30 33 87 52 39 90 55 35 87 27 7 88 32 58 29 0 0 14 25 43 35 184 -34 89 51 7 87 14 7 90 15 59 86 48 44 87 53 48 28 0 0 14 25 22 36 184 -34 89 11 32 86 35 21 89 36 16 86 10 5 87 14 25 27 0 0 14 25 0 37 183 -34 88 31 47 85 56 18 88 56 23 85 31 8 86 34 46 26 0 0 14 24 38 38 182 -33 87 51 49 85 16 56 88 16 19 84 51 51 85 54 48 25 0 0 14 24 15 39 181 -33 87 11 36 84 37 12 87 36 1 84 12 11 85 14 30 24 0 0 14 23 51 40 180 -32 86 31 5 83 57 5 86 55 26 83 32 7 84 33 49 23 0 0 14 23 27 41 179 -32 85 50 15 83 16 32 86 14 32 82 51 36 83 52 43 22 0 0 14 23 2 42 178 -31 85 9 3 82 35 29 85 33 17 82 10 34 83 11 9 21 0 0 14 22 36 43 177 -31 84 27 25 81 53 56 84 51 39 81 29 1 82 29 3 20 0 0 14 22 9 44 176 -30 83 45 20 81 11 48 84 9 34 80 46 51 81 46 24 19 0 0 14 21 42 45 175 -29 83 2 45 80 29 2 83 26 59 80 4 3 81 3 8 18 0 0 14 21 15 46 174 -29 82 19 37 79 45 37 82 43 52 79 20 34 80 19 12 17 0 0 14 20 46 47 173 -28 81 35 52 79 1 27 82 0 10 78 36 19 79 34 33 16 0 0 14 20 17 47 172 -27 80 51 27 78 16 30 81 15 50 77 51 15 78 49 6 15 0 0 14 19 47 48 170 -26 80 6 19 77 30 41 80 30 47 77 5 19 78 2 48 14 0 0 14 19 17 49 169 -26 79 20 24 76 43 57 79 44 59 76 18 25 77 15 35 13 0 0 14 18 45 50 167 -25 78 33 38 75 56 12 78 58 21 75 30 30 76 27 22 12 0 0 14 18 13 51 166 -24 77 45 56 75 7 23 78 10 49 74 41 28 75 38 3 11 0 0 14 17 41 51 164 -23 76 57 15 74 17 23 77 22 18 73 51 13 74 47 35 10 0 0 14 17 7 52 162 -22 76 7 29 73 26 7 76 32 45 72 59 41 73 55 50 9 0 0 14 16 33 53 161 -21 75 16 33 72 33 28 75 42 3 72 6 43 73 2 43 8 0 0 14 15 58 53 159 -20 74 24 20 71 39 19 74 50 6 71 12 13 72 8 5 7 0 0 14 15 22 54 157 -19 73 30 44 70 43 33 73 56 49 70 16 3 71 11 50 6 0 0 14 14 46 54 155 -18 72 35 38 69 45 59 73 2 3 69 18 3 70 13 47 5 0 0 14 14 8 55 153 -17 71 38 54 68 46 30 72 5 42 68 18 3 69 13 48 4 0 0 14 13 30 55 150 -15 70 40 22 67 44 52 71 7 37 67 15 51 68 11 40 3 0 0 14 12 51 55 148 -14 69 39 53 66 40 53 70 7 37 66 11 14 67 7 11 2 0 0 14 12 10 55 146 -13 68 37 15 65 34 18 69 5 31 65 3 55 66 0 5 1 0 0 14 11 29 55 143 -12 67 32 14 64 24 49 68 1 8 63 53 37 64 50 5 0 0 0 14 10 47 55 141 -10 66 24 37 63 12 7 66 54 12 62 39 57 63 36 50 - 1 0 0 14 10 3 55 138 -9 65 14 4 61 55 46 65 44 27 61 22 30 Latitude Latitude Latitude Latitude 62 0 0 - 2 15 4 14 9 7 55 135 -7 - 3 31 51 - 0 56 45 - 3 56 6 - 0 31 21 61 0 0 - 2 59 12 14 8 33 55 134 -6 - 4 14 59 - 1 41 55 - 4 38 57 - 1 16 51 60 0 0 - 3 41 33 14 8 0 54 132 -4 - 4 56 24 - 2 25 15 - 5 20 4 - 2 0 31 59 0 0 - 4 22 10 14 7 27 54 130 -3 - 5 36 7 - 3 6 49 - 5 59 31 - 2 42 24 58 0 0 - 5 1 4 14 6 55 53 129 -2 - 6 14 10 - 3 46 38 - 6 37 18 - 3 22 30 57 0 0 - 5 38 19 14 6 23 53 127 -1 - 6 50 36 - 4 24 44 - 7 13 28 - 4 0 54 Uncertainty in time = +/- 7 secs [Prediction of 2008 Sep 26.0] Data for the target star ------------------------ * name: HIP 102498 * constellation : Capricornus * J2000 position with proper motion and parallax to date of event [h,m,s ; °,',"] RA: 20 46 20.2221 DE: -26 10 34.465 * position source: Pos: UCAC2, pm: UCAC2, pi:Hipparcos * standard error: RA,DE ["]: ( .019, .019 ) * V mag [mag]: 9.0 * B mag [mag]: 9.8 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (128) Nemesis approx. diameter [km]: 188 approx. diameter ["]: .138 distance from Earth [AU]: 1.87900 * orbital information: orbit source: Preston date of fit: 2008 Sep 25 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 718 number of rejected observations: 156 time covered by the observations: 1904 Nov 17 - 2008 Sep 25 1 sigma uncertainty ellipse (major, minor, PA): 0.012, 0.009, 81° remarks: * orbital elements for (128) Nemesis : Mean anomaly = 319.37034108 deg Arg. of pericenter = 302.43994586 deg Long. of node = 76.43575914 deg Inclination = 6.24898597 deg Eccentricity = 0.12495620 Semimajor axis = 2.75066750 AU Perihelion dist = 2.40695454 AU Mag: H = 7.50, G = 0.15 Epoch of elements : MJD 54740.59100000 TDT (2008 Oct 01.591) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Oct 1 128 Nemesis 14h 11.4m UT 9.0 20 46 20.222-26 10 34.47HIP 102498 9.8 11.9 188 42.7 1.879 0.642 7.77 88.0514 -26.178 -35.47 -3.48 14.1900 -0.37991 0.42115 1.84317 1.65969 0.00471 0.00169 2000 319.242658200810 1.00000302.439946 76.435759 6.2489860.12495620 2.7506675 2.4069545 7.5 5.00.15 RATE 2.1604630 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.023 0.021 87 1.16 0.022 0 54735.5020081001_102498 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Sep 26, 02:19 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org