IOTA/IOTA-ES occultation update for (500) Selinur / HIP 37914 event on 2012 Sep 16, 01:39 UT Visible from Africa Summary ------- On 2012 Sep 16 UT, the 44 km diameter asteroid (500) Selinur will occult a 7.6 mag star in the constellation Gemini for observers along a path across Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 7.1 mag to 14.7 mag (the magnitude of the asteroid) for at most 1.4 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: . The event at a glimpse ---------------------- * Rank: 90 * date and approx. time of event: 2012 Sep 16, 01:36 - 2012 Sep 16, 01:37 UT * geocentric midpoint of event [JD]: 2456186.56885 * magnitude of target star: 7.6 * magnitude drop [mag]: 7.1 * estimated maximum duration [s]: 1.4 * Moon: 0 % sunlit, 60° distance * Sun: 59° distance * rough path description: Africa The occultation path -------------------- * approximate projected width [km]: 48 * 1 sigma uncertainty interval [path widths]: +/- 0.53 * 1 sigma uncertainty interval [seconds]: +/- 1.1 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .018 +/- .011) * 1 sigma uncertainty ellipse (major, minor, PA): ( .018", .011", 101° ) * approx speed of asteroid's shadow [km/s]: 31.1958 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 37914 by 500 Selinur on 2012 Sep 16 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 11 0 0 - 8 11 31 1 36 1 0 66 -53 - 8 25 42 - 7 57 21 .. .. .. - 7 42 23 12 0 0 - 7 45 24 1 36 1 1 66 -53 - 7 59 32 - 7 31 16 - 8 14 34 - 7 16 20 13 0 0 - 7 19 39 1 36 1 2 66 -52 - 7 33 46 - 7 5 34 - 7 48 45 - 6 50 39 14 0 0 - 6 54 17 1 36 2 3 66 -51 - 7 8 22 - 6 40 14 - 7 23 19 - 6 25 22 15 0 0 - 6 29 20 1 36 2 4 66 -50 - 6 43 22 - 6 15 18 - 6 58 17 - 6 0 29 16 0 0 - 6 4 46 1 36 2 5 66 -49 - 6 18 46 - 5 50 47 - 6 33 39 - 5 35 59 17 0 0 - 5 40 37 1 36 3 7 65 -48 - 5 54 35 - 5 26 40 - 6 9 26 - 5 11 54 18 0 0 - 5 16 53 1 36 3 8 65 -47 - 5 30 49 - 5 2 58 - 5 45 38 - 4 48 14 19 0 0 - 4 53 34 1 36 4 9 65 -46 - 5 7 29 - 4 39 42 - 5 22 15 - 4 25 0 20 0 0 - 4 30 42 1 36 5 10 65 -45 - 4 44 34 - 4 16 51 - 4 59 18 - 4 2 12 21 0 0 - 4 8 16 1 36 5 11 65 -44 - 4 22 6 - 3 54 27 - 4 36 48 - 3 39 50 22 0 0 - 3 46 17 1 36 6 12 65 -43 - 4 0 5 - 3 32 30 - 4 14 45 - 3 17 55 23 0 0 - 3 24 45 1 36 7 13 65 -42 - 3 38 31 - 3 11 0 - 3 53 9 - 2 56 27 24 0 0 - 3 3 40 1 36 8 14 65 -41 - 3 17 25 - 2 49 57 - 3 32 0 - 2 35 27 25 0 0 - 2 43 4 1 36 9 15 65 -40 - 2 56 46 - 2 29 23 - 3 11 20 - 2 14 54 26 0 0 - 2 22 55 1 36 10 16 65 -39 - 2 36 36 - 2 9 16 - 2 51 7 - 1 54 50 27 0 0 - 2 3 15 1 36 11 17 65 -38 - 2 16 54 - 1 49 38 - 2 31 23 - 1 35 13 28 0 0 - 1 44 4 1 36 12 18 65 -37 - 1 57 41 - 1 30 29 - 2 12 8 - 1 16 6 29 0 0 - 1 25 22 1 36 14 19 64 -36 - 1 38 57 - 1 11 48 - 1 53 22 - 0 57 27 30 0 0 - 1 7 9 1 36 15 20 64 -35 - 1 20 42 - 0 53 37 - 1 35 5 - 0 39 18 31 0 0 - 0 49 25 1 36 17 21 64 -34 - 1 2 57 - 0 35 55 - 1 17 18 - 0 21 38 32 0 0 - 0 32 11 1 36 18 22 64 -33 - 0 45 41 - 0 18 43 - 1 0 1 - 0 4 28 33 0 0 - 0 15 28 1 36 20 23 64 -32 - 0 28 55 - 0 2 1 - 0 43 13 0 12 12 34 0 0 0 0 46 1 36 21 24 64 -31 - 0 12 40 0 14 11 - 0 26 56 0 28 23 35 0 0 0 16 30 1 36 23 25 64 -30 0 3 5 0 29 53 - 0 11 9 0 44 3 36 0 0 0 31 43 1 36 25 26 64 -29 0 18 20 0 45 4 0 4 7 0 59 13 37 0 0 0 46 25 1 36 27 27 64 -28 0 33 3 0 59 45 0 18 52 1 13 52 38 0 0 1 0 36 1 36 29 28 64 -27 0 47 16 1 13 55 0 33 7 1 28 0 39 0 0 1 14 17 1 36 30 29 63 -25 1 0 59 1 27 34 0 46 51 1 41 38 40 0 0 1 27 27 1 36 32 30 63 -24 1 14 10 1 40 43 1 0 3 1 54 45 41 0 0 1 40 5 1 36 35 31 63 -23 1 26 49 1 53 20 1 12 44 2 7 20 42 0 0 1 52 12 1 36 37 32 63 -22 1 38 58 2 5 26 1 24 54 2 19 25 43 0 0 2 3 48 1 36 39 33 63 -21 1 50 35 2 17 0 1 36 32 2 30 58 44 0 0 2 14 53 1 36 41 34 63 -20 2 1 40 2 28 3 1 47 39 2 42 0 45 0 0 2 25 25 1 36 43 35 63 -19 2 12 14 2 38 35 1 58 14 2 52 31 46 0 0 2 35 26 1 36 46 36 62 -18 2 22 17 2 48 35 2 8 18 3 2 30 47 0 0 2 44 56 1 36 48 37 62 -17 2 31 47 2 58 4 2 17 49 3 11 57 48 0 0 2 53 54 1 36 50 38 62 -16 2 40 46 3 7 0 2 26 49 3 20 53 49 0 0 3 2 19 1 36 53 39 62 -15 2 49 12 3 15 25 2 35 17 3 29 17 50 0 0 3 10 13 1 36 55 40 62 -14 2 57 7 3 23 18 2 43 13 3 37 9 51 0 0 3 17 35 1 36 58 41 61 -13 3 4 30 3 30 39 2 50 36 3 44 29 52 0 0 3 24 25 1 37 1 42 61 -12 3 11 21 3 37 29 2 57 28 3 51 18 53 0 0 3 30 43 1 37 3 43 61 -11 3 17 39 3 43 46 3 3 47 3 57 34 54 0 0 3 36 29 1 37 6 44 60 -10 3 23 26 3 49 31 3 9 34 4 3 19 55 0 0 3 41 43 1 37 9 45 60 -9 3 28 40 3 54 44 3 14 49 4 8 31 56 0 0 3 46 24 1 37 12 46 60 -8 3 33 22 3 59 25 3 19 32 4 13 12 57 0 0 3 50 34 1 37 14 47 59 -7 3 37 32 4 3 34 3 23 42 4 17 20 58 0 0 3 54 11 1 37 17 48 59 -6 3 41 10 4 7 11 3 27 20 4 20 57 59 0 0 3 57 16 1 37 20 48 58 -5 3 44 15 4 10 16 3 30 26 4 24 1 60 0 0 3 59 49 1 37 23 49 58 -4 3 46 48 4 12 48 3 32 59 4 26 33 61 0 0 4 1 49 1 37 26 50 57 -3 3 48 48 4 14 48 3 35 0 4 28 33 62 0 0 4 3 17 1 37 29 51 57 -2 3 50 16 4 16 16 3 36 28 4 30 0 63 0 0 4 4 12 1 37 32 52 56 -1 3 51 12 4 17 11 3 37 24 4 30 56 64 0 0 4 4 36 1 37 35 53 55 0 3 51 36 4 17 35 3 37 47 4 31 19 Uncertainty in time = +/- 1 secs Prediction of 2012 Jul 21.0 Data for the target star ------------------------ * name: HIP 37914 * constellation : Gemini * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 07 46 10.3114 DE: +23 32 55.161 * position source: mpos:HIP2 pm:HIP2 plx:HIP2 * standard error: RA,DE ["]: ( .013, .009 ) * V mag [mag]: 7.6 * B mag [mag]: 7.6 * Apparent position with proper motion RA(deg): 116.7345355110 DE(deg): 23.5155018425 * Equation of equinoxes (radians) : 0.000067068412125 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (500) Selinur approx. diameter [km]: 44 approx. diameter ["]: .021 distance from Earth [AU]: 2.91600 * orbital information: orbit source: Preston date of fit: 2012 Jul 21 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 911 number of rejected observations: 80 time covered by the observations: 1903 Jan 16 - 2012 Jan 22 1 sigma uncertainty ellipse (major, minor, PA): 0.013, 0.007, 111° remarks: * orbital elements for (500) Selinur : Mean anomaly = 72.59385006 deg Arg. of pericenter = 74.98876464 deg Long. of node = 289.94282391 deg Inclination = 9.76978999 deg Eccentricity = 0.14616189 Semimajor axis = 2.61320889 AU Perihelion dist = 2.23125735 AU Mag: H = 9.16, G = 0.15 Epoch of elements : MJD 56186.06900000 TDT (2012 Sep 16.069) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 16 500 Selinur 1h 39.1m UT 7.6 7 46 10.311 23 32 55.16HIP 37914 7.6 14.7 44 1.4 2.916 3.740 -13.18 96.3426 23.552 153.93 2.54 1.6524 -0.10019 -0.38254 17.05700 -4.36942 -0.00474 0.00098 2000 71.1778612012 910.00000 74.988765289.942824 9.7697900.14616189 2.6132089 2.2312573 9.3 5.00.15 RATE 2.3331510 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.018 0.011 101 1.53 0.011 0 0 4 1 056129.0020120916__37914 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 22, 03:55 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org