IOTA/IOTA-ES occultation update for (141) Lumen / TYC 5776-00344-1 event on 2012 Sep 23, 21:03 UT Visible from Russia Summary ------- On 2012 Sep 23 UT, the 145 km diameter asteroid (141) Lumen will occult a 10.5 mag star in the constellation Aquarius for observers along a path across Russia. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.4 mag to 11.5 mag (the magnitude of the asteroid) for at most 40.8 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: 2012 Sep 23, 21:02 - 2012 Sep 23, 21:03 UT * geocentric midpoint of event [JD]: 2456194.3770375 * magnitude of target star: 10.5 * magnitude drop [mag]: 1.4 * estimated maximum duration [s]: 40.8 * Moon: 62 % sunlit, 34° distance * Sun: 137° distance * rough path description: Russia The occultation path -------------------- * approximate projected width [km]: 2061 * 1 sigma uncertainty interval [path widths]: +/- 0.25 * 1 sigma uncertainty interval [seconds]: +/- 9.2 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .041 +/- .029) * 1 sigma uncertainty ellipse (major, minor, PA): ( .041", .028", 74° ) * approx speed of asteroid's shadow [km/s]: 3.5517 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 5776-00344-1 by 141 Lumen on 2012 Sep 23 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 75 19 12 53 0 0 21 3 32 1 253 -31 ... .. .. 62 38 23 ... .. .. 59 19 56 74 50 59 52 0 0 21 3 6 2 252 -32 ... .. .. 62 49 17 ... .. .. 59 34 3 75 31 59 51 0 0 21 2 33 2 253 -32 ... .. .. 63 11 21 ... .. .. 59 57 13 Uncertainty in time = +/- 11 secs Prediction of 2012 Aug 26.0 Data for the target star ------------------------ * name: TYC 5776-00344-1 * constellation : Aquarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 21 14 49.3008 DE: -09 41 14.793 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .030, .025 ) * V mag [mag]: 10.5 * B mag [mag]: 11.2 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (141) Lumen approx. diameter [km]: 145 approx. diameter ["]: .148 distance from Earth [AU]: 1.34700 * orbital information: orbit source: Preston date of fit: 2012 Aug 25 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 796 number of rejected observations: 85 time covered by the observations: 1918 Jan 15 - 2012 Aug 11 1 sigma uncertainty ellipse (major, minor, PA): 0.030, 0.014, 58° remarks: * orbital elements for (141) Lumen : Mean anomaly = 333.78918449 deg Arg. of pericenter = 58.35398093 deg Long. of node = 318.54306290 deg Inclination = 11.88621502 deg Eccentricity = 0.21294801 Semimajor axis = 2.66592119 AU Perihelion dist = 2.09821857 AU Mag: H = 8.35, G = 0.15 Epoch of elements : MJD 56193.87700000 TDT (2012 Sep 23.877) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 23 141 Lumen 21h 2.9m UT 10.5 21 14 49.301- 9 41 14.79TYC 5776-00344-1 11.2 11.5 145 40.8 1.347 -0.705 7.87 -0.1386 -9.688 -137.71 -0.49 21.0489 0.59975 0.79709 -1.60158 1.20565 0.00366 0.00072 2000 332.9113172012 920.00000 58.353981318.543063 11.8862150.21294801 2.6659212 2.0982186 8.2 5.00.15 RATE 2.2642950 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.041 0.028 74 1.25 0.037 0 0-2-3 056165.0020120923_0344-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Aug 25, 23:05 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org