IOTA/IOTA-ES occultation update for (699) Hela / TYC 0755-01660-1 event on 2008 Dec 03, 16:54 UT Visible from Australia Summary ------- On 2008 Dec 03 UT, the 15 km diameter asteroid (699) Hela will occult a 9.6 mag star in the constellation Monoceros for observers along a path across Australia. In the case of an occultation, the combined light of the asteroid and the star will drop by 6.3 mag to 15.9 mag (the magnitude of the asteroid) for at most 1.1 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: UCAC. The event at a glimpse ---------------------- * Rank: 19 * date and approx. time of event: 2008 Dec 03, 16:49 - 2008 Dec 03, 17:01 UT * magnitude of target star: 9.6 * magnitude drop [mag]: 6.3 * estimated maximum duration [s]: 1.1 * Moon: 30 % sunlit, 144° distance * Sun: 147° distance * rough path description: Australia The occultation path -------------------- * approximate projected width [km]: 17 * 1 sigma uncertainty interval [path widths]: +/- 3.53 * 1 sigma uncertainty interval [seconds]: +/- 5.0 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .055 +/- .031) * 1 sigma uncertainty ellipse (major, minor, PA): ( .056", .029", 102° ) * approx speed of asteroid's shadow [km/s]: 13.0861 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 0755-01660-1 by 699 Hela on 2008 Dec 3 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 58 0 0 -47 40 21 17 1 53 0 73 -10 -47 35 30 -47 45 11 .. .. .. -48 19 26 59 0 0 -47 27 30 17 1 52 1 72 -10 -47 22 40 -47 32 21 .. .. .. -48 6 41 60 0 0 -47 14 20 17 1 52 2 71 -11 -47 9 29 -47 19 12 .. .. .. -47 53 36 61 0 0 -47 0 51 17 1 52 2 70 -12 -46 55 59 -47 5 43 .. .. .. -47 40 12 62 0 0 -46 47 2 17 1 52 3 70 -12 -46 42 10 -46 51 55 -46 7 52 -47 26 28 63 0 0 -46 32 54 17 1 51 4 69 -13 -46 28 1 -46 37 47 -45 53 38 -47 12 24 64 0 0 -46 18 25 17 1 51 5 68 -13 -46 13 32 -46 23 19 -45 39 5 -46 58 1 65 0 0 -46 3 38 17 1 50 5 67 -14 -45 58 44 -46 8 32 -45 24 13 -46 43 18 66 0 0 -45 48 31 17 1 50 6 67 -15 -45 43 36 -45 53 26 -45 9 1 -46 28 16 67 0 0 -45 33 4 17 1 49 7 66 -15 -45 28 9 -45 38 0 -44 53 29 -46 12 54 68 0 0 -45 17 18 17 1 48 8 65 -16 -45 12 22 -45 22 14 -44 37 38 -45 57 13 69 0 0 -45 1 12 17 1 47 8 65 -16 -44 56 16 -45 6 9 -44 21 28 -45 41 12 70 0 0 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27 24 -18 37 25 -17 52 11 -19 12 55 138 0 0 -18 8 33 16 55 55 60 357 -37 -18 3 33 -18 13 33 -17 28 23 -18 48 59 139 0 0 -17 44 55 16 55 47 61 355 -37 -17 39 55 -17 49 54 -17 4 49 -18 25 16 140 0 0 -17 21 30 16 55 39 61 353 -37 -17 16 31 -17 26 29 -16 41 29 -18 1 47 141 0 0 -16 58 19 16 55 30 61 351 -36 -16 53 21 -17 3 18 -16 18 22 -17 38 32 142 0 0 -16 35 23 16 55 22 61 348 -36 -16 30 25 -16 40 21 -15 55 31 -17 15 31 143 0 0 -16 12 42 16 55 13 62 346 -36 -16 7 45 -16 17 39 -15 32 54 -16 52 46 144 0 0 -15 50 17 16 55 5 62 344 -35 -15 45 20 -15 55 14 -15 10 33 -16 30 16 145 0 0 -15 28 8 16 54 56 62 342 -35 -15 23 12 -15 33 4 -14 48 29 -16 8 3 146 0 0 -15 6 15 16 54 48 62 340 -34 -15 1 20 -15 11 11 -14 26 41 -15 46 5 147 0 0 -14 44 40 16 54 39 62 338 -34 -14 39 45 -14 49 35 -14 5 10 -15 24 25 148 0 0 -14 23 22 16 54 31 62 336 -33 -14 18 27 -14 28 16 -13 43 56 -15 3 3 149 0 0 -14 2 21 16 54 22 62 334 -33 -13 57 28 -14 7 15 -13 23 0 -14 41 58 150 0 0 -13 41 39 16 54 14 62 332 -32 -13 36 46 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177 0 0 - 6 37 43 16 50 42 47 295 -14 - 6 33 3 - 6 42 24 - 6 0 8 - 7 15 32 178 0 0 - 6 27 35 16 50 35 46 294 -13 - 6 22 55 - 6 32 15 - 5 50 3 - 7 5 21 179 0 0 - 6 17 52 16 50 28 45 293 -12 - 6 13 12 - 6 22 32 - 5 40 22 - 6 55 35 180 0 0 - 6 8 35 16 50 22 44 293 -11 - 6 3 56 - 6 13 15 - 5 31 8 - 6 46 16 -179 0 0 - 5 59 44 16 50 15 44 292 -11 - 5 55 5 - 6 4 24 - 5 22 19 - 6 37 22 -178 0 0 - 5 51 19 16 50 9 43 292 -10 - 5 46 40 - 5 55 58 - 5 13 56 - 6 28 55 -177 0 0 - 5 43 20 16 50 2 42 291 -9 - 5 38 41 - 5 47 59 - 5 5 59 - 6 20 54 -176 0 0 - 5 35 47 16 49 56 41 290 -8 - 5 31 9 - 5 40 26 - 4 58 28 - 6 13 20 -175 0 0 - 5 28 41 16 49 50 40 290 -7 - 5 24 3 - 5 33 20 - 4 51 24 - 6 6 11 -174 0 0 - 5 22 1 16 49 44 39 290 -6 - 5 17 23 - 5 26 39 - 4 44 46 - 5 59 30 -173 0 0 - 5 15 48 16 49 38 38 289 -5 - 5 11 10 - 5 20 26 - 4 38 34 - 5 53 15 -172 0 0 - 5 10 1 16 49 32 37 289 -5 - 5 5 24 - 5 14 39 - 4 32 49 - 5 47 27 -171 0 0 - 5 4 41 16 49 26 37 288 -4 - 5 0 4 - 5 9 19 - 4 27 30 - 5 42 6 -170 0 0 - 4 59 48 16 49 21 36 288 -3 - 4 55 11 - 5 4 26 - 4 22 38 - 5 37 11 -169 0 0 - 4 55 22 16 49 16 35 288 -2 - 4 50 45 - 5 0 0 - 4 18 13 - 5 32 44 -168 0 0 - 4 51 23 16 49 10 34 287 -1 - 4 46 46 - 4 56 0 - 4 14 15 - 5 28 44 -167 0 0 - 4 47 51 16 49 5 33 287 0 - 4 43 14 - 4 52 28 - 4 10 44 - 5 25 11 Uncertainty in time = +/- 6 secs [Prediction of 2008 Nov 26.0] Data for the target star ------------------------ * name: TYC 0755-01660-1 * constellation : Monoceros * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 06 52 01.2497 DE: +11 31 52.246 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .019, .019 ) * V mag [mag]: 9.6 * B mag [mag]: 9.9 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (699) Hela approx. diameter [km]: 15 approx. diameter ["]: .011 distance from Earth [AU]: 1.83700 * orbital information: orbit source: Preston date of fit: 2008 Oct 29 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 910 number of rejected observations: 23 time covered by the observations: 1902 Nov 21 - 2007 Oct 03 1 sigma uncertainty ellipse (major, minor, PA): 0.053, 0.022, 104° remarks: * orbital elements for (699) Hela : Mean anomaly = 72.22694330 deg Arg. of pericenter = 91.28747102 deg Long. of node = 242.75054141 deg Inclination = 15.30080861 deg Eccentricity = 0.40722514 Semimajor axis = 2.61570602 AU Perihelion dist = 1.55052476 AU Mag: H = 11.15, G = 0.15 Epoch of elements : MJD 54803.70500000 TDT (2008 Dec 03.705) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Dec 3 699 Hela 16h 54.7m UT 9.6 6 52 1.250 11 31 52.25TYC 0755-01660-1 9.9 15.9 15 1.1 1.837 -2.252 -12.49 136.4343 11.534 -76.17 -22.22 16.9121 0.16673 -0.44085 -6.91009 -2.60890 -0.00294 0.00127 2000 71.36374820081130.00000 91.287471242.750541 15.3008090.40722514 2.6157060 1.550524811.7 5.00.15 RATE 2.3298110 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.056 0.029 102 4.53 0.040 0 54796.5020081203_1660-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Nov 26, 23:34 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org