IOTA/IOTA-ES occultation update for (19) Fortuna / TYC 6277-00490-1 event on 2008 Mar 25, 11:11 UT Visible from N Canada Summary ------- On 2008 Mar 25 UT, the 221 km diameter asteroid (19) Fortuna will occult a 11.6 mag star in the constellation Sagittarius for observers along a path across N Canada. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.2 mag to 12.4 mag (the magnitude of the asteroid) for at most 13.5 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 25, 11:09 - 2008 Mar 25, 11:10 UT * midpoint of event [JD]: 2454550.96559167 * magnitude of target star: 11.6 * magnitude drop [mag]: 1.2 * estimated maximum duration [s]: 13.5 * Moon: 87 % sunlit, 48° distance * Sun: 91° distance * rough path description: N Canada The occultation path -------------------- * approximate projected width [km]: 1779 * 1 sigma uncertainty interval [path widths]: +/- 0.20 * 1 sigma uncertainty interval [seconds]: +/- 2.7 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .026 +/- .024) * 1 sigma uncertainty ellipse (major, minor, PA): ( .026", .024", 90° ) * approx speed of asteroid's shadow [km/s]: 16.3333 * website for maps: http://lunar-occultations.com/iota/asteroids/astrndx.htm http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6277-00490-1 by 19 Fortuna on 2008 Mar 25 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 Latitude Latitude Latitude Latitude - 81 0 0 62 34 56 11 10 44 5 176 0 55 43 2 .. .. .. 53 54 13 .. .. .. - 82 0 0 62 19 55 11 10 40 5 175 -1 55 35 13 .. .. .. 53 47 7 .. .. .. - 83 0 0 62 7 28 11 10 37 6 174 -1 55 28 35 .. .. .. 53 41 4 .. .. .. - 84 0 0 61 57 24 11 10 34 6 173 -2 55 23 7 .. .. .. 53 36 5 .. .. .. - 85 0 0 61 49 33 11 10 30 6 172 -2 55 18 47 .. .. .. 53 32 9 .. .. .. - 86 0 0 61 43 50 11 10 27 6 171 -3 55 15 37 .. .. .. 53 29 16 .. .. .. - 87 0 0 61 40 11 11 10 24 6 170 -3 55 13 35 .. .. .. 53 27 25 .. .. .. - 88 0 0 61 38 33 11 10 20 6 169 -4 55 12 42 .. .. .. 53 26 37 .. .. .. - 89 0 0 61 38 56 11 10 17 6 168 -4 55 12 57 .. .. .. 53 26 51 .. .. .. - 90 0 0 61 41 18 11 10 14 5 167 -5 55 14 21 .. .. .. 53 28 8 .. .. .. - 91 0 0 61 45 43 11 10 11 5 167 -5 55 16 52 .. .. .. 53 30 27 .. .. .. - 92 0 0 61 52 12 11 10 8 5 166 -6 55 20 33 .. .. .. 53 33 49 .. .. .. - 93 0 0 62 0 51 11 10 5 5 165 -6 55 25 22 .. .. .. 53 38 14 .. .. .. - 94 0 0 62 11 45 11 10 2 5 164 -6 55 31 21 .. .. .. 53 43 42 .. .. .. - 95 0 0 62 25 5 11 10 0 4 163 -7 55 38 29 .. .. .. 53 50 12 .. .. .. - 96 0 0 62 41 2 11 9 57 4 162 -7 55 46 47 .. .. .. 53 57 47 .. .. .. - 97 0 0 62 59 56 11 9 55 3 161 -8 55 56 17 .. .. .. 54 6 25 .. .. .. - 98 0 0 63 22 13 11 9 53 3 160 -8 56 6 59 .. .. .. 54 16 7 .. .. .. - 99 0 0 63 48 37 11 9 51 2 159 -8 56 18 53 .. .. .. 54 26 55 .. .. .. -100 0 0 64 20 17 11 9 49 2 158 -8 56 32 2 .. .. .. 54 38 47 .. .. .. -101 0 0 64 59 32 11 9 48 1 157 -8 56 46 26 .. .. .. 54 51 46 .. .. .. Uncertainty in time = +/- 3 secs [Prediction of 2008 Feb 14.0] Data for the target star ------------------------ * name: TYC 6277-00490-1 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 18 16 35.9351 DE: -22 16 03.177 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .024, .023 ) * V mag [mag]: 11.6 * B mag [mag]: 12.0 * Apparent position with proper motion RA(deg): 274.2767290466 DE(deg): -22.2664726345 * Equation of equinoxes (radians) : 0.000040677589975 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (19) Fortuna approx. diameter [km]: 221 approx. diameter ["]: .122 distance from Earth [AU]: 2.50500 * orbital information: orbit source: Preston date of fit: 2008 Feb 13 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1551 number of rejected observations: 256 time covered by the observations: 1900 Feb 12 - 2007 Jul 25 1 sigma uncertainty ellipse (major, minor, PA): 0.009, 0.007, 88° remarks: * orbital elements for (19) Fortuna : Mean anomaly = 231.69063709 deg Arg. of pericenter = 181.85264398 deg Long. of node = 211.35923119 deg Inclination = 1.57287406 deg Eccentricity = 0.15862333 Semimajor axis = 2.44271958 AU Perihelion dist = 2.05524727 AU Mag: H = 7.13, G = 0.10 Epoch of elements : MJD 54550.46600000 TDT (2008 Mar 25.466) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Mar 25 19 Fortuna 11h 10.5m UT 11.6 18 16 35.935-22 16 3.18TYC 6277-00490-1 12.0 12.4 221 13.5 2.505 2.324 2.54 -76.7489 -22.267 13.86 2.06 11.1742 -0.07691 0.98927 9.19060 0.72267 -0.00573 -0.00016 2000 231.5703332008 325.00000181.852644211.359231 1.5728740.15862333 2.4427196 2.0552473 7.1 5.00.10 RATE 2.5816280 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.026 0.024 90 1.20 0.024 0 54510.5020080325_0490-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Feb 14, 19:36 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org