IOTA/IOTA-ES occultation update for (1637) Swings / TYC 1822-00941-1 event on 2012 Aug 20, 07:21 UT Visible from Brazil, Argentina Summary ------- On 2012 Aug 20 UT, the 44 km diameter asteroid (1637) Swings will occult a 9.7 mag star in the constellation Taurus for observers along a path across Brazil, Argentina. In the case of an occultation, the combined light of the asteroid and the star will drop by 6.7 mag to 16.4 mag (the magnitude of the asteroid) for at most 2.3 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: 48 * date and approx. time of event: 2012 Aug 20, 07:16 - 2012 Aug 20, 07:20 UT * geocentric midpoint of event [JD]: 2456159.80657083 * magnitude of target star: 9.7 * magnitude drop [mag]: 6.7 * estimated maximum duration [s]: 2.3 * Moon: 9 % sunlit, 118° distance * Sun: 83° distance * rough path description: Brazil, Argentina The occultation path -------------------- * approximate projected width [km]: 48 * 1 sigma uncertainty interval [path widths]: +/- 1.34 * 1 sigma uncertainty interval [seconds]: +/- 3.5 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .032 +/- .026) * 1 sigma uncertainty ellipse (major, minor, PA): ( .032", .025", 75° ) * approx speed of asteroid's shadow [km/s]: 19.2556 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of TYC 1822-00941-1 by 1637 Swings on 2012 Aug 20 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 - 76 0 0 -44 36 32 7 16 22 1 50 -48 -44 53 14 -44 19 52 .. .. .. -43 35 24 - 75 0 0 -44 0 21 7 16 22 2 49 -47 -44 17 8 -43 43 36 -45 2 20 -42 58 57 - 74 0 0 -43 23 23 7 16 23 2 49 -47 -43 40 15 -43 6 34 -44 25 40 -42 21 42 - 73 0 0 -42 45 38 7 16 23 3 48 -47 -43 2 34 -42 28 44 -43 48 12 -41 43 40 - 72 0 0 -42 7 6 7 16 23 4 47 -47 -42 24 7 -41 50 8 -43 9 56 -41 4 52 - 71 0 0 -41 27 47 7 16 24 5 47 -46 -41 44 52 -41 10 45 -42 30 53 -40 25 18 - 70 0 0 -40 47 42 7 16 24 6 46 -46 -41 4 51 -40 30 35 -41 51 3 -39 44 58 - 69 0 0 -40 6 50 7 16 25 7 45 -46 -40 24 4 -39 49 40 -41 10 26 -39 3 52 - 68 0 0 -39 25 14 7 16 26 8 45 -45 -39 42 30 -39 8 0 -40 29 3 -38 22 2 - 67 0 0 -38 42 52 7 16 27 10 44 -45 -39 0 12 -38 25 34 -39 46 54 -37 39 27 - 66 0 0 -37 59 46 7 16 28 11 43 -44 -38 17 9 -37 42 25 -39 4 1 -36 56 9 - 65 0 0 -37 15 56 7 16 30 12 43 -44 -37 33 23 -36 58 32 -38 20 23 -36 12 8 - 64 0 0 -36 31 25 7 16 31 13 42 -44 -36 48 54 -36 13 58 -37 36 2 -35 27 26 - 63 0 0 -35 46 12 7 16 33 14 41 -43 -36 3 44 -35 28 42 -36 50 59 -34 42 3 - 62 0 0 -35 0 18 7 16 34 15 41 -42 -35 17 53 -34 42 47 -36 5 15 -33 56 1 - 61 0 0 -34 13 47 7 16 36 16 40 -42 -34 31 24 -33 56 12 -35 18 51 -33 9 22 - 60 0 0 -33 26 37 7 16 38 17 40 -41 -33 44 16 -33 9 1 -34 31 49 -32 22 5 - 59 0 0 -32 38 52 7 16 40 18 39 -41 -32 56 33 -32 21 15 -33 44 10 -31 34 14 - 58 0 0 -31 50 33 7 16 43 20 38 -40 -32 8 15 -31 32 54 -32 55 56 -30 45 50 - 57 0 0 -31 1 42 7 16 45 21 38 -39 -31 19 25 -30 44 2 -32 7 9 -29 56 55 - 56 0 0 -30 12 20 7 16 48 22 37 -38 -30 30 4 -29 54 39 -31 17 50 -29 7 30 - 55 0 0 -29 22 29 7 16 51 23 37 -38 -29 40 14 -29 4 48 -30 28 1 -28 17 38 - 54 0 0 -28 32 13 7 16 54 24 36 -37 -28 49 57 -28 14 31 -29 37 45 -27 27 20 - 53 0 0 -27 41 32 7 16 57 25 36 -36 -27 59 16 -27 23 50 -28 47 4 -26 36 40 - 52 0 0 -26 50 29 7 17 1 27 35 -35 -27 8 13 -26 32 48 -27 56 0 -25 45 38 - 51 0 0 -25 59 7 7 17 4 28 34 -34 -26 16 50 -25 41 26 -27 4 36 -24 54 18 - 50 0 0 -25 7 28 7 17 8 29 34 -34 -25 25 10 -24 49 48 -26 12 53 -24 2 43 - 49 0 0 -24 15 34 7 17 12 30 33 -33 -24 33 15 -23 57 56 -25 20 54 -23 10 54 - 48 0 0 -23 23 28 7 17 16 32 33 -32 -23 41 8 -23 5 52 -24 28 43 -22 18 53 - 47 0 0 -22 31 13 7 17 20 33 32 -31 -22 48 51 -22 13 38 -23 36 21 -21 26 45 - 46 0 0 -21 38 52 7 17 25 34 31 -30 -21 56 28 -21 21 19 -22 43 52 -20 34 31 - 45 0 0 -20 46 26 7 17 29 35 31 -29 -21 3 59 -20 28 55 -21 51 17 -19 42 13 - 44 0 0 -19 53 59 7 17 34 37 30 -28 -20 11 30 -19 36 31 -20 58 40 -18 49 56 - 43 0 0 -19 1 33 7 17 39 38 29 -27 -19 19 1 -18 44 8 -20 6 4 -17 57 40 - 42 0 0 -18 9 11 7 17 44 39 29 -26 -18 26 36 -17 51 49 -19 13 30 -17 5 30 - 41 0 0 -17 16 56 7 17 49 40 28 -25 -17 34 17 -16 59 37 -18 21 2 -16 13 27 - 40 0 0 -16 24 50 7 17 54 41 27 -24 -16 42 8 -16 7 34 -17 28 43 -15 21 34 - 39 0 0 -15 32 55 7 18 0 43 27 -23 -15 50 10 -15 15 44 -16 36 35 -14 29 53 - 38 0 0 -14 41 16 7 18 5 44 26 -21 -14 58 26 -14 24 8 -15 44 40 -13 38 28 - 37 0 0 -13 49 53 7 18 11 45 25 -20 -14 6 58 -13 32 49 -14 53 1 -12 47 20 - 36 0 0 -12 58 49 7 18 17 46 24 -19 -13 15 50 -12 41 50 -14 1 42 -11 56 32 - 35 0 0 -12 8 7 7 18 23 47 24 -18 -12 25 4 -11 51 12 -13 10 43 -11 6 6 - 34 0 0 -11 17 49 7 18 29 49 23 -17 -11 34 41 -11 0 59 -12 20 7 -10 16 5 - 33 0 0 -10 27 56 7 18 35 50 22 -16 -10 44 44 -10 11 11 -11 29 57 - 9 26 30 - 32 0 0 - 9 38 32 7 18 41 51 21 -15 - 9 55 15 - 9 21 52 -10 40 14 - 8 37 24 - 31 0 0 - 8 49 39 7 18 48 52 20 -14 - 9 6 16 - 8 33 4 - 9 51 2 - 7 48 49 - 30 0 0 - 8 1 17 7 18 54 53 19 -12 - 8 17 49 - 7 44 47 - 9 2 21 - 7 0 46 - 29 0 0 - 7 13 29 7 19 1 54 18 -11 - 7 29 56 - 6 57 4 - 8 14 13 - 6 13 17 - 28 0 0 - 6 26 17 7 19 7 55 16 -10 - 6 42 38 - 6 9 57 - 7 26 41 - 5 26 24 - 27 0 0 - 5 39 42 7 19 14 56 15 -9 - 5 55 58 - 5 23 28 - 6 39 46 - 4 40 9 - 26 0 0 - 4 53 45 7 19 20 57 14 -8 - 5 9 56 - 4 37 37 - 5 53 30 - 3 54 32 - 25 0 0 - 4 8 29 7 19 27 58 13 -7 - 4 24 34 - 3 52 26 - 5 7 53 - 3 9 36 - 24 0 0 - 3 23 54 7 19 34 59 11 -6 - 3 39 54 - 3 7 57 - 4 22 57 - 2 25 21 - 23 0 0 - 2 40 2 7 19 41 60 9 -4 - 2 55 56 - 2 24 10 - 3 38 45 - 1 41 49 - 22 0 0 - 1 56 53 7 19 47 61 8 -3 - 2 12 42 - 1 41 7 - 2 55 15 - 0 59 0 - 21 0 0 - 1 14 29 7 19 54 62 6 -2 - 1 30 12 - 0 58 48 - 2 12 31 - 0 16 57 - 20 0 0 - 0 32 51 7 20 1 62 4 -1 - 0 48 29 - 0 17 15 - 1 30 32 0 24 22 Uncertainty in time = +/- 4 secs Prediction of 2012 Jul 8.0 Data for the target star ------------------------ * name: TYC 1822-00941-1 * constellation : Taurus * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 04 04 14.1705 DE: +26 51 40.492 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .020, .021 ) * V mag [mag]: 9.7 * B mag [mag]: 11.1 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (1637) Swings approx. diameter [km]: 44 approx. diameter ["]: .019 distance from Earth [AU]: 3.15000 * orbital information: orbit source: Preston date of fit: 2012 Jul 07 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1108 number of rejected observations: 35 time covered by the observations: 1907 Apr 05 - 2012 Jan 04 1 sigma uncertainty ellipse (major, minor, PA): 0.026, 0.014, 67° remarks: * orbital elements for (1637) Swings : Mean anomaly = 151.59985812 deg Arg. of pericenter = 231.05638623 deg Long. of node = 21.58649160 deg Inclination = 14.09522722 deg Eccentricity = 0.04344835 Semimajor axis = 3.07473135 AU Perihelion dist = 2.94113936 AU Mag: H = 10.39, G = 0.15 Epoch of elements : MJD 56159.30700000 TDT (2012 Aug 20.307) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Aug 20 1637 Swings 7h 21.5m UT 9.7 4 4 14.170 26 51 40.49TYC 1822-00941-1 11.1 16.4 44 2.3 3.150 1.967 15.07 -18.3432 26.857 70.47 12.28 7.3577 0.18828 -0.33055 9.43252 5.39902 -0.00560 -0.00103 2000 149.8984712012 811.00000231.056386 21.586492 14.0952270.04344835 3.0747314 2.941139310.4 5.00.15 RATE 1.8280720 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.032 0.025 75 2.34 0.026 0 0 5 2 056116.0020120820_0941-1 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 07, 23:31 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org