IOTA/IOTA-ES occultation update for (15) Eunomia / TYC 6684-00387-1 event on 2009 Apr 03, 07:27 UT Visible from Summary ------- On 2009 Apr 03 UT, the 255 km diameter asteroid (15) Eunomia will occult a 12.1 mag star in the constellation Hydra for observers along a path across . In the case of an occultation, the combined light of the asteroid and the star will drop by 0.1 mag to 9.8 mag (the magnitude of the asteroid) for at most 17.7 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. The event at a glimpse ---------------------- * Rank: 99 * date and approx. time of event: 1899 Dec 30, 00:00 - 1899 Dec 30, 00:00 UT * magnitude of target star: 12.1 * magnitude drop [mag]: 0.1 * estimated maximum duration [s]: 17.7 * Moon: 58 % sunlit, 87° distance * Sun: 162° distance * rough path description: The occultation path -------------------- * approximate projected width [km]: 255 * 1 sigma uncertainty interval [path widths]: +/- 0.16 * 1 sigma uncertainty interval [seconds]: +/- 2.7 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .027 +/- .026) * 1 sigma uncertainty ellipse (major, minor, PA): ( .027", .026", 94° ) * approx speed of asteroid's shadow [km/s]: 14.3965 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 6684-00387-1 by 15 Eunomia on 2009 Apr 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 Uncertainty in time = +/- 3 secs [Prediction of 2008 Mar 20.0] Data for the target star ------------------------ * name: TYC 6684-00387-1 * constellation : Hydra * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 12 45 09.4072 DE: -23 25 43.859 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .024, .024 ) * V mag [mag]: 12.1 * B mag [mag]: 12.7 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (15) Eunomia approx. diameter [km]: 255 approx. diameter ["]: .163 distance from Earth [AU]: 2.15400 * orbital information: orbit source: Preston date of fit: 2008 Mar 19 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 1614 number of rejected observations: 173 time covered by the observations: 1905 Jan 15 - 2008 Mar 08 1 sigma uncertainty ellipse (major, minor, PA): 0.012, 0.009, 113° remarks: * orbital elements for (15) Eunomia : Mean anomaly = 161.05228720 deg Arg. of pericenter = 97.82186932 deg Long. of node = 293.26346222 deg Inclination = 11.73824166 deg Eccentricity = 0.18776091 Semimajor axis = 2.64315777 AU Perihelion dist = 2.14687607 AU Mag: H = 5.27, G = 0.23 Epoch of elements : MJD 54924.31100000 TDT (2009 Apr 03.311) ------ occelmnt file for Occult BEGIN ----------------------------------- 2009 Apr 3 15 Eunomia 7h 27.5m UT 12.1 12 45 9.407-23 25 43.86TYC 6684-00387-1 12.7 9.8 255 17.7 2.154 -2.272 11.08 -112.3513 -23.431 68.95 5.40 7.4583 0.33785 0.95387 -7.65989 2.71199 0.00015 0.00179 2000 160.0635122009 330.00000 97.821869293.263462 11.7382420.18776091 2.6431578 2.1468761 5.3 5.00.23 RATE 2.2936090 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.027 0.026 94 1.16 0.026 0 54545.5020090403_0387-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 20, 06:43 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org