IOTA/IOTA-ES occultation update for (1304) Arosa / HIP 41950 event on 2012 Sep 02, 10:24 UT Visible from Central America Summary ------- On 2012 Sep 02 UT, the 48 km diameter asteroid (1304) Arosa will occult a 9.9 mag star in the constellation Cancer for observers along a path across Central America. In the case of an occultation, the combined light of the asteroid and the star will drop by 5.0 mag to 14.9 mag (the magnitude of the asteroid) for at most 1.2 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC. The event at a glimpse ---------------------- * Rank: 57 * date and approx. time of event: 2012 Sep 02, 10:21 - 2012 Sep 02, 10:22 UT * geocentric midpoint of event [JD]: 2456172.93354167 * magnitude of target star: 9.9 * magnitude drop [mag]: 5.0 * estimated maximum duration [s]: 1.2 * Moon: 96 % sunlit, 121° distance * Sun: 37° distance * rough path description: Central America The occultation path -------------------- * approximate projected width [km]: 48 * 1 sigma uncertainty interval [path widths]: +/- 1.10 * 1 sigma uncertainty interval [seconds]: +/- 1.3 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .019 +/- .018) * 1 sigma uncertainty ellipse (major, minor, PA): ( .019", .018", 89° ) * approx speed of asteroid's shadow [km/s]: 39.4257 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 41950 by 1304 Arosa on 2012 Sep 2 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 - 98 0 0 - 0 36 48 10 21 37 1 64 -32 - 0 51 23 - 0 22 13 - 1 23 30 0 9 50 - 97 0 0 - 0 7 9 10 21 37 2 64 -31 - 0 21 43 0 7 25 - 0 53 49 0 39 27 - 96 0 0 0 22 21 10 21 37 3 64 -30 0 7 48 0 36 55 - 0 24 16 1 8 54 - 95 0 0 0 51 43 10 21 38 4 64 -29 0 37 10 1 6 15 0 5 8 1 38 13 - 94 0 0 1 20 54 10 21 38 5 64 -28 1 6 22 1 35 25 0 34 22 2 7 21 - 93 0 0 1 49 54 10 21 38 6 64 -27 1 35 23 2 4 24 1 3 26 2 36 18 - 92 0 0 2 18 43 10 21 38 7 64 -26 2 4 13 2 33 12 1 32 18 3 5 3 - 91 0 0 2 47 19 10 21 39 8 64 -25 2 32 51 3 1 47 2 0 58 3 33 36 - 90 0 0 3 15 43 10 21 39 9 64 -24 3 1 15 3 30 10 2 29 25 4 1 56 - 89 0 0 3 43 53 10 21 40 11 64 -23 3 29 26 3 58 18 2 57 39 4 30 2 - 88 0 0 4 11 48 10 21 41 12 64 -22 3 57 23 4 26 13 3 25 39 4 57 53 - 87 0 0 4 39 29 10 21 41 13 64 -21 4 25 5 4 53 52 3 53 24 5 25 30 - 86 0 0 5 6 54 10 21 42 14 64 -19 4 52 31 5 21 15 4 20 53 5 52 50 - 85 0 0 5 34 2 10 21 43 15 64 -18 5 19 41 5 48 23 4 48 6 6 19 54 - 84 0 0 6 0 54 10 21 44 16 64 -17 5 46 34 6 15 13 5 15 2 6 46 42 - 83 0 0 6 27 28 10 21 44 17 64 -16 6 13 10 6 41 46 5 41 41 7 13 11 - 82 0 0 6 53 44 10 21 45 18 65 -15 6 39 28 7 8 0 6 8 2 7 39 23 - 81 0 0 7 19 42 10 21 46 19 65 -14 7 5 27 7 33 57 6 34 4 8 5 15 - 80 0 0 7 45 20 10 21 47 20 65 -13 7 31 7 7 59 34 6 59 48 8 30 49 - 79 0 0 8 10 39 10 21 48 21 65 -12 7 56 27 8 24 51 7 25 12 8 56 3 - 78 0 0 8 35 38 10 21 50 23 65 -11 8 21 28 8 49 48 7 50 16 9 20 57 - 77 0 0 9 0 16 10 21 51 24 65 -10 8 46 8 9 14 25 8 14 59 9 45 30 - 76 0 0 9 24 34 10 21 52 25 65 -9 9 10 27 9 38 40 8 39 22 10 9 42 - 75 0 0 9 48 29 10 21 53 26 65 -8 9 34 24 10 2 34 9 3 23 10 33 32 - 74 0 0 10 12 3 10 21 55 27 66 -7 9 57 59 10 26 7 9 27 2 10 57 1 - 73 0 0 10 35 15 10 21 56 28 66 -6 10 21 13 10 49 16 9 50 19 11 20 7 - 72 0 0 10 58 4 10 21 57 29 66 -5 10 44 3 11 12 4 10 13 13 11 42 50 - 71 0 0 11 20 30 10 21 59 30 66 -4 11 6 31 11 34 28 10 35 45 12 5 11 - 70 0 0 11 42 32 10 22 0 31 66 -3 11 28 35 11 56 29 10 57 53 12 27 8 - 69 0 0 12 4 12 10 22 2 32 66 -2 11 50 16 12 18 6 11 19 37 12 48 42 - 68 0 0 12 25 27 10 22 4 33 67 -1 12 11 33 12 39 20 11 40 58 13 9 52 Uncertainty in time = +/- 1 secs Prediction of 2012 Apr 8.0 Data for the target star ------------------------ * name: HIP 41950 * constellation : Cancer * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 08 33 04.8670 DE: +26 17 05.697 * position source: mpos:UCAC2 pm:UCAC2 plx:HIP2 * standard error: RA,DE ["]: ( .013, .015 ) * V mag [mag]: 9.9 * B mag [mag]: 10.6 * Apparent position with proper motion RA(deg): 128.4592791094 DE(deg): 26.2398798699 * Equation of equinoxes (radians) : 0.000070159650558 * Diameter [mas]: 0 * remarks:HIP2 pm issue, UCAC2 OK Data for the minor planet ------------------------- * general information: (number) name: (1304) Arosa approx. diameter [km]: 48 approx. diameter ["]: .016 distance from Earth [AU]: 4.10000 * orbital information: orbit source: Preston date of fit: 2012 Apr 08 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 941 number of rejected observations: 41 time covered by the observations: 1908 Dec 16 - 2012 Feb 19 1 sigma uncertainty ellipse (major, minor, PA): 0.014, 0.009, 88° remarks: * orbital elements for (1304) Arosa : Mean anomaly = 252.34538485 deg Arg. of pericenter = 148.08397892 deg Long. of node = 86.60614352 deg Inclination = 18.98996575 deg Eccentricity = 0.11591624 Semimajor axis = 3.19698702 AU Perihelion dist = 2.82640431 AU Mag: H = 9.16, G = 0.15 Epoch of elements : MJD 56172.43400000 TDT (2012 Sep 02.434) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 2 1304 Arosa 10h 24.3m UT 9.9 8 33 4.867 26 17 5.70HIP 41950 10.6 14.9 48 1.2 4.100 3.536 -4.17 -9.7799 26.286 23.82 7.68 10.4050 -0.00962 -0.10337 22.16810 -1.94190 -0.00312 0.00140 2000 251.9257102012 831.00000148.083979 86.606144 18.9899660.11591624 3.1969870 2.8264043 8.6 5.00.15 RATE 1.7242200 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.019 0.018 89 2.10 0.018 0 0 0-3 056025.0020120902__41950 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 08, 04:14 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org