IOTA/IOTA-ES occultation update for (2154) Underhill / HIP 48472 event on 2008 Dec 01, 15:25 UT Visible from E Australia Summary ------- On 2008 Dec 01 UT, the 21 km diameter asteroid (2154) Underhill will occult a 8.1 mag star in the constellation Leo for observers along a path across E Australia. In the case of an occultation, the combined light of the asteroid and the star will drop by 8.8 mag to 16.9 mag (the magnitude of the asteroid) for at most 2.1 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: 15 * date and approx. time of event: 2008 Dec 01, 15:18 - 2008 Dec 01, 15:27 UT * magnitude of target star: 8.1 * magnitude drop [mag]: 8.8 * estimated maximum duration [s]: 2.1 * Moon: 13 % sunlit, 149° distance * Sun: 107° distance * rough path description: E Australia The occultation path -------------------- * approximate projected width [km]: 30 * 1 sigma uncertainty interval [path widths]: +/- 4.53 * 1 sigma uncertainty interval [seconds]: +/- 9.5 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .076 +/- .074) * 1 sigma uncertainty ellipse (major, minor, PA): ( .079", .071", 127° ) * approx speed of asteroid's shadow [km/s]: 10.0372 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 48472 by 2154 Underhill on 2008 Dec 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 ' " Latitude Latitude Latitude Latitude 134 0 0 -32 44 51 15 18 28 1 63 -35 -32 53 51 -32 35 53 -34 16 39 .. .. .. 135 0 0 -32 19 54 15 18 28 2 62 -35 -32 28 52 -32 10 58 -33 51 23 .. .. .. 136 0 0 -31 55 18 15 18 29 3 62 -36 -32 4 14 -31 46 23 -33 26 28 .. .. .. 137 0 0 -31 31 2 15 18 30 4 61 -36 -31 39 57 -31 22 9 -33 1 54 .. .. .. 138 0 0 -31 7 9 15 18 31 5 61 -36 -31 16 1 -30 58 17 -32 37 42 .. .. .. 139 0 0 -30 43 37 15 18 32 6 60 -36 -30 52 28 -30 34 48 -32 13 52 .. .. .. 140 0 0 -30 20 29 15 18 34 6 60 -37 -30 29 18 -30 11 41 -31 50 26 .. .. .. 141 0 0 -29 57 45 15 18 35 7 59 -37 -30 6 32 -29 48 58 -31 27 24 -28 30 36 142 0 0 -29 35 25 15 18 37 8 59 -37 -29 44 11 -29 26 40 -31 4 46 -28 8 32 143 0 0 -29 13 30 15 18 40 9 58 -37 -29 22 14 -29 4 47 -30 42 34 -27 46 53 144 0 0 -28 52 0 15 18 42 10 58 -37 -29 0 43 -28 43 19 -30 20 47 -27 25 39 145 0 0 -28 30 57 15 18 45 11 57 -37 -28 39 39 -28 22 18 -29 59 28 -27 4 52 146 0 0 -28 10 21 15 18 48 12 57 -37 -28 19 1 -28 1 43 -29 38 35 -26 44 31 147 0 0 -27 50 12 15 18 51 13 56 -37 -27 58 50 -27 41 36 -29 18 10 -26 24 37 148 0 0 -27 30 32 15 18 55 14 56 -37 -27 39 8 -27 21 57 -28 58 13 -26 5 10 149 0 0 -27 11 19 15 18 59 15 55 -37 -27 19 54 -27 2 46 -28 38 46 -25 46 12 150 0 0 -26 52 36 15 19 3 16 55 -37 -27 1 9 -26 44 4 -28 19 47 -25 27 43 151 0 0 -26 34 22 15 19 7 17 54 -37 -26 42 54 -26 25 51 -28 1 18 -25 9 42 152 0 0 -26 16 38 15 19 11 18 53 -36 -26 25 8 -26 8 8 -27 43 20 -24 52 11 153 0 0 -25 59 24 15 19 16 19 53 -36 -26 7 53 -25 50 56 -27 25 52 -24 35 11 154 0 0 -25 42 41 15 19 21 19 52 -36 -25 51 9 -25 34 14 -27 8 55 -24 18 40 155 0 0 -25 26 29 15 19 26 20 52 -36 -25 34 56 -25 18 4 -26 52 30 -24 2 41 156 0 0 -25 10 49 15 19 32 21 51 -35 -25 19 15 -25 2 25 -26 36 37 -23 47 12 157 0 0 -24 55 41 15 19 37 22 51 -35 -25 4 5 -24 47 18 -26 21 17 -23 32 15 158 0 0 -24 41 5 15 19 43 23 50 -35 -24 49 28 -24 32 43 -26 6 29 -23 17 51 159 0 0 -24 27 2 15 19 49 24 49 -34 -24 35 24 -24 18 41 -25 52 15 -23 3 58 160 0 0 -24 13 32 15 19 55 25 49 -34 -24 21 53 -24 5 12 -25 38 33 -22 50 38 161 0 0 -24 0 35 15 20 2 26 48 -34 -24 8 55 -23 52 16 -25 25 26 -22 37 51 162 0 0 -23 48 12 15 20 9 26 48 -33 -23 56 31 -23 39 54 -25 12 53 -22 25 37 163 0 0 -23 36 23 15 20 15 27 47 -33 -23 44 41 -23 28 5 -25 0 54 -22 13 57 164 0 0 -23 25 8 15 20 23 28 46 -32 -23 33 25 -23 16 51 -24 49 30 -22 2 51 165 0 0 -23 14 27 15 20 30 29 46 -32 -23 22 44 -23 6 12 -24 38 41 -21 52 18 166 0 0 -23 4 21 15 20 37 30 45 -31 -23 12 37 -22 56 7 -24 28 27 -21 42 20 167 0 0 -22 54 51 15 20 45 30 44 -31 -23 3 6 -22 46 37 -24 18 49 -21 32 56 168 0 0 -22 45 55 15 20 53 31 43 -30 -22 54 9 -22 37 42 -24 9 46 -21 24 7 169 0 0 -22 37 35 15 21 1 32 43 -30 -22 45 49 -22 29 22 -24 1 19 -21 15 53 170 0 0 -22 29 50 15 21 9 33 42 -29 -22 38 4 -22 21 39 -23 53 29 -21 8 15 171 0 0 -22 22 42 15 21 17 33 41 -28 -22 30 54 -22 14 30 -23 46 14 -21 1 11 172 0 0 -22 16 9 15 21 26 34 40 -28 -22 24 21 -22 7 58 -23 39 37 -20 54 43 173 0 0 -22 10 12 15 21 34 35 39 -27 -22 18 24 -22 2 2 -23 33 35 -20 48 51 174 0 0 -22 4 52 15 21 43 35 38 -26 -22 13 3 -21 56 42 -23 28 11 -20 43 34 175 0 0 -22 0 8 15 21 52 36 38 -26 -22 8 19 -21 51 59 -23 23 24 -20 38 54 176 0 0 -21 56 1 15 22 1 37 37 -25 -22 4 12 -21 47 52 -23 19 14 -20 34 49 177 0 0 -21 52 31 15 22 10 37 36 -24 -22 0 41 -21 44 21 -23 15 41 -20 31 21 178 0 0 -21 49 37 15 22 20 38 35 -24 -21 57 47 -21 41 28 -23 12 45 -20 28 29 179 0 0 -21 47 20 15 22 29 38 34 -23 -21 55 30 -21 39 11 -23 10 27 -20 26 13 180 0 0 -21 45 40 15 22 39 39 33 -22 -21 53 50 -21 37 31 -23 8 46 -20 24 34 -179 0 0 -21 44 37 15 22 48 40 32 -21 -21 52 47 -21 36 28 -23 7 43 -20 23 31 -178 0 0 -21 44 11 15 22 58 40 31 -21 -21 52 21 -21 36 2 -23 7 17 -20 23 5 -177 0 0 -21 44 23 15 23 8 41 29 -20 -21 52 33 -21 36 14 -23 7 30 -20 23 16 -176 0 0 -21 45 11 15 23 18 41 28 -19 -21 53 22 -21 37 2 -23 8 20 -20 24 3 -175 0 0 -21 46 37 15 23 28 41 27 -18 -21 54 48 -21 38 28 -23 9 48 -20 25 27 -174 0 0 -21 48 41 15 23 39 42 26 -17 -21 56 51 -21 40 31 -23 11 53 -20 27 28 -173 0 0 -21 51 21 15 23 49 42 25 -17 -21 59 32 -21 43 11 -23 14 37 -20 30 6 -172 0 0 -21 54 39 15 23 59 43 24 -16 -22 2 50 -21 46 29 -23 17 58 -20 33 20 -171 0 0 -21 58 34 15 24 10 43 22 -15 -22 6 46 -21 50 23 -23 21 57 -20 37 12 -170 0 0 -22 3 6 15 24 20 43 21 -14 -22 11 18 -21 54 55 -23 26 34 -20 41 40 -169 0 0 -22 8 16 15 24 31 43 20 -13 -22 16 28 -22 0 4 -23 31 49 -20 46 44 -168 0 0 -22 14 2 15 24 41 44 19 -12 -22 22 15 -22 5 50 -23 37 41 -20 52 26 -167 0 0 -22 20 26 15 24 52 44 17 -11 -22 28 40 -22 12 13 -23 44 11 -20 58 43 -166 0 0 -22 27 27 15 25 3 44 16 -10 -22 35 41 -22 19 13 -23 51 19 -21 5 38 -165 0 0 -22 35 4 15 25 14 44 15 -9 -22 43 20 -22 26 50 -23 59 4 -21 13 9 -164 0 0 -22 43 19 15 25 24 44 13 -9 -22 51 35 -22 35 4 -24 7 26 -21 21 16 -163 0 0 -22 52 10 15 25 35 44 12 -8 -23 0 27 -22 43 54 -24 16 26 -21 29 59 -162 0 0 -23 1 38 15 25 46 44 11 -7 -23 9 55 -22 53 21 -24 26 3 -21 39 19 -161 0 0 -23 11 42 15 25 57 44 9 -6 -23 20 0 -23 3 25 -24 36 16 -21 49 14 -160 0 0 -23 22 22 15 26 8 44 8 -5 -23 30 42 -23 14 4 -24 47 7 -21 59 45 -159 0 0 -23 33 39 15 26 18 44 6 -4 -23 41 59 -23 25 20 -24 58 34 -22 10 52 -158 0 0 -23 45 31 15 26 29 44 5 -3 -23 53 53 -23 37 11 -25 10 37 -22 22 34 -157 0 0 -23 57 59 15 26 40 44 4 -2 -24 6 22 -23 49 38 -25 23 17 -22 34 52 -156 0 0 -24 11 3 15 26 51 44 2 -1 -24 19 27 -24 2 40 -25 36 32 -22 47 44 -155 0 0 -24 24 42 15 27 2 44 1 0 -24 33 7 -24 16 18 -25 50 23 -23 1 11 Uncertainty in time = +/- 10 secs [Prediction of 2008 Nov 26.0] Data for the target star ------------------------ * name: HIP 48472 * constellation : Leo * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 09 53 04.4203 DE: +22 07 23.949 * position source: Pos: HIP2, pm: HIP2, pi:HIP2 * standard error: RA,DE ["]: ( .015, .010 ) * V mag [mag]: 8.1 * B mag [mag]: 9.8 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (2154) Underhill approx. diameter [km]: 21 approx. diameter ["]: .016 distance from Earth [AU]: 1.82400 * orbital information: orbit source: Preston date of fit: 2008 Nov 26 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 727 number of rejected observations: 8 time covered by the observations: 1958 Apr 08 - 2008 Feb 02 1 sigma uncertainty ellipse (major, minor, PA): 0.078, 0.070, 128° remarks: * orbital elements for (2154) Underhill : Mean anomaly = 357.56950124 deg Arg. of pericenter = 120.49965804 deg Long. of node = 0.96808494 deg Inclination = 7.75459773 deg Eccentricity = 0.12465977 Semimajor axis = 2.63594618 AU Perihelion dist = 2.30734972 AU Mag: H = 12.77, G = 0.15 Epoch of elements : MJD 54801.64300000 TDT (2008 Dec 01.643) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Dec 1 2154 Underhill 15h 25.9m UT 8.1 9 53 4.420 22 7 23.95HIP 48472 9.8 16.9 21 2.1 1.824 1.937 -4.63 -154.0576 22.124 -54.16 -21.92 15.4312 -0.11987 -0.70460 5.58319 -0.96075 -0.00524 0.00164 2000 357.19111320081130.00000120.499658 0.968085 7.7545980.12465977 2.6359462 2.307349712.7 5.00.15 RATE 2.3030290 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.079 0.071 127 5.53 0.072 0 54796.5020081201__48472 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Nov 26, 23:23 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org