IOTA/IOTA-ES occultation update for (640) Brambilla / TYC 5197-00100-1 event on 2008 May 10, 18:00 UT Visible from China Summary ------- On 2008 May 10 UT, the 81 km diameter asteroid (640) Brambilla will occult a 12.0 mag star in the constellation Aquarius for observers along a path across China. In the case of an occultation, the combined light of the asteroid and the star will drop by 2.6 mag to 14.5 mag (the magnitude of the asteroid) for at most 4.5 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: 84 * date and approx. time of event: 2008 May 10, 18:00 - 2008 May 10, 18:01 UT * midpoint of event [JD]: 2454597.25046667 * magnitude of target star: 12.0 * magnitude drop [mag]: 2.6 * estimated maximum duration [s]: 4.5 * Moon: 35 % sunlit, 157° distance * Sun: 91° distance * rough path description: China The occultation path -------------------- * approximate projected width [km]: 653 * 1 sigma uncertainty interval [path widths]: +/- 0.61 * 1 sigma uncertainty interval [seconds]: +/- 3.1 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .031 +/- .022) * 1 sigma uncertainty ellipse (major, minor, PA): ( .031", .022", 84° ) * approx speed of asteroid's shadow [km/s]: 17.9143 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 5197-00100-1 by 640 Brambilla on 2008 May 10 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 95 34 35 55 0 0 18 1 16 2 97 -17 102 57 32 ... .. .. 107 55 42 ... .. .. 98 12 3 54 0 0 18 1 11 3 99 -18 104 0 39 ... .. .. 108 35 13 ... .. .. 99 39 12 53 0 0 18 1 6 4 100 -19 104 44 53 ... .. .. 109 3 0 ... .. .. 100 33 19 52 0 0 18 1 0 5 101 -20 105 14 11 ... .. .. 109 20 38 ... .. .. 101 5 10 51 0 0 18 0 55 6 101 -20 105 30 54 ... .. .. 109 29 11 ... .. .. 101 19 27 50 0 0 18 0 49 6 101 -21 105 36 30 ... .. .. 109 29 25 ... .. .. 101 18 23 49 0 0 18 0 43 6 101 -22 105 31 48 ... .. .. 109 21 50 ... .. .. 101 2 40 48 0 0 18 0 36 6 101 -23 105 17 13 ... .. .. 109 6 42 ... .. .. 100 31 45 47 0 0 18 0 30 6 100 -24 104 52 43 ... .. .. 108 44 5 ... .. .. 99 43 23 46 0 0 18 0 23 6 100 -26 104 17 49 ... .. .. 108 13 50 ... .. .. 98 31 54 45 0 0 18 0 16 5 99 -27 103 31 25 ... .. .. 107 35 35 ... .. .. 96 40 52 44 0 0 18 0 9 4 97 -28 102 31 27 ... .. .. 106 48 37 ... .. .. Latitude Latitude Latitude Latitude 101 0 0 47 53 19 18 0 36 6 101 -24 42 50 45 .. .. .. 39 43 25 .. .. .. 100 0 0 46 18 2 18 0 25 6 100 -25 42 15 17 .. .. .. 39 17 43 .. .. .. 99 0 0 45 20 52 18 0 18 5 99 -26 41 45 51 .. .. .. .. .. .. .. .. .. 98 0 0 44 39 31 18 0 14 5 98 -27 41 21 33 .. .. .. .. .. .. .. .. .. 97 0 0 44 8 17 18 0 10 4 98 -28 41 1 49 .. .. .. .. .. .. .. .. .. 96 0 0 43 44 39 18 0 7 3 97 -28 40 46 11 .. .. .. .. .. .. .. .. .. 95 0 0 43 27 17 18 0 4 3 96 -29 40 34 23 .. .. .. .. .. .. .. .. .. 94 0 0 43 15 23 18 0 3 2 95 -29 40 26 13 .. .. .. .. .. .. .. .. .. 93 0 0 43 8 31 18 0 2 1 95 -29 40 21 32 .. .. .. .. .. .. .. .. .. 92 0 0 43 6 25 18 0 1 0 94 -29 40 20 16 .. .. .. .. .. .. .. .. .. Uncertainty in time = +/- 3 secs [Prediction of 2008 Feb 17.0] Data for the target star ------------------------ * name: TYC 5197-00100-1 * constellation : Aquarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 21 10 42.7483 DE: -02 45 29.327 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .025, .019 ) * V mag [mag]: 12.0 * B mag [mag]: 12.4 * Apparent position with proper motion RA(deg): 317.7895531750 DE(deg): -2.7254997600 * Equation of equinoxes (radians) : 0.000041069586580 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (640) Brambilla approx. diameter [km]: 81 approx. diameter ["]: .041 distance from Earth [AU]: 2.73600 * orbital information: orbit source: Preston date of fit: 2008 Feb 16 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 770 number of rejected observations: 64 time covered by the observations: 1907 Aug 29 - 2007 Sep 13 1 sigma uncertainty ellipse (major, minor, PA): 0.018, 0.011, 71° remarks: * orbital elements for (640) Brambilla : Mean anomaly = 26.13860585 deg Arg. of pericenter = 33.57198481 deg Long. of node = 235.02232073 deg Inclination = 13.37342959 deg Eccentricity = 0.08181394 Semimajor axis = 3.16086861 AU Perihelion dist = 2.90226549 AU Mag: H = 9.07, G = 0.15 Epoch of elements : MJD 54596.75000000 TDT (2008 May 10.750) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 May 10 640 Brambilla 18h 0.7m UT 12.0 21 10 42.748- 2 45 29.33TYC 5197-00100-1 12.4 14.5 81 4.5 2.736 1.645 21.17 178.6045 -2.763 -91.07 17.86 18.0112 -0.64626 0.75296 7.67305 6.58504 -0.00540 -0.00174 2000 24.9547522008 5 4.00000 33.571985235.022321 13.3734300.08181394 3.1608686 2.9022655 9.0 5.00.15 RATE 1.7538580 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.031 0.022 84 1.61 0.025 0 54513.5020080510_0100-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Mar 31, 04:29 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org