IOTA/IOTA-ES occultation update for (17) Thetis / 2UCAC 24957023 event on 2008 Mar 27, 09:22 UT Visible from Bolivia, Chile Summary ------- On 2008 Mar 27 UT, the 90 km diameter asteroid (17) Thetis will occult a 12.5 mag star in the constellation Sagittarius for observers along a path across Bolivia, Chile. In the case of an occultation, the combined light of the asteroid and the star will drop by 0.6 mag to 12.2 mag (the magnitude of the asteroid) for at most 3.8 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: 54 * date and approx. time of event: 2008 Mar 27, 09:17 - 2008 Mar 27, 09:21 UT * midpoint of event [JD]: 2454552.8904375 * magnitude of target star: 12.5 * magnitude drop [mag]: 0.6 * estimated maximum duration [s]: 3.8 * Moon: 73 % sunlit, 36° distance * Sun: 83° distance * rough path description: Bolivia, Chile The occultation path -------------------- * approximate projected width [km]: 90 * 1 sigma uncertainty interval [path widths]: +/- 1.16 * 1 sigma uncertainty interval [seconds]: +/- 4.2 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .071 +/- .071) * 1 sigma uncertainty ellipse (major, minor, PA): ( .071", .071", 90° ) * approx speed of asteroid's shadow [km/s]: 23.6262 * website for maps: http://lunar-occultations.com/iota/asteroids/astrndx.htm http://www.asteroidoccultation.com Path Coordinates: Occultation of 2UCAC 24957023 by 17 Thetis on 2008 Mar 27 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 -131 0 0 - 5 47 36 9 17 44 0 108 -82 - 6 13 19 - 5 21 53 - 7 12 59 .. .. .. -130 0 0 - 6 7 24 9 17 44 1 108 -81 - 6 33 7 - 5 41 42 - 7 32 45 - 4 42 4 -129 0 0 - 6 27 5 9 17 44 2 108 -80 - 6 52 46 - 6 1 24 - 7 52 22 - 5 1 48 -128 0 0 - 6 46 37 9 17 44 3 108 -79 - 7 12 17 - 6 20 57 - 8 11 51 - 5 21 24 -127 0 0 - 7 6 1 9 17 44 4 108 -78 - 7 31 40 - 6 40 22 - 8 31 11 - 5 40 50 -126 0 0 - 7 25 15 9 17 45 5 108 -77 - 7 50 53 - 6 59 37 - 8 50 21 - 6 0 8 -125 0 0 - 7 44 19 9 17 45 6 108 -76 - 8 9 56 - 7 18 42 - 9 9 22 - 6 19 16 -124 0 0 - 8 3 13 9 17 46 7 107 -75 - 8 28 49 - 7 37 38 - 9 28 12 - 6 38 14 -123 0 0 - 8 21 57 9 17 47 9 107 -74 - 8 47 31 - 7 56 23 - 9 46 52 - 6 57 2 -122 0 0 - 8 40 30 9 17 47 10 107 -73 - 9 6 3 - 8 14 57 -10 5 21 - 7 15 39 -121 0 0 - 8 58 52 9 17 48 11 107 -72 - 9 24 24 - 8 33 20 -10 23 38 - 7 34 5 -120 0 0 - 9 17 2 9 17 49 12 107 -71 - 9 42 33 - 8 51 31 -10 41 44 - 7 52 20 -119 0 0 - 9 35 0 9 17 50 13 107 -70 -10 0 30 - 9 9 31 -10 59 38 - 8 10 23 -118 0 0 - 9 52 46 9 17 51 14 107 -69 -10 18 14 - 9 27 18 -11 17 19 - 8 28 13 -117 0 0 -10 10 20 9 17 52 15 106 -68 -10 35 46 - 9 44 53 -11 34 48 - 8 45 51 -116 0 0 -10 27 40 9 17 54 16 106 -67 -10 53 5 -10 2 15 -11 52 4 - 9 3 16 -115 0 0 -10 44 47 9 17 55 17 106 -66 -11 10 11 -10 19 24 -12 9 6 - 9 20 29 -114 0 0 -11 1 41 9 17 57 18 106 -65 -11 27 3 -10 36 19 -12 25 55 - 9 37 27 -113 0 0 -11 18 21 9 17 58 19 106 -64 -11 43 42 -10 53 0 -12 42 30 - 9 54 12 -112 0 0 -11 34 47 9 18 0 20 105 -63 -12 0 6 -11 9 27 -12 58 50 -10 10 42 -111 0 0 -11 50 58 9 18 1 21 105 -62 -12 16 15 -11 25 40 -13 14 57 -10 26 59 -110 0 0 -12 6 54 9 18 3 22 105 -61 -12 32 10 -11 41 38 -13 30 48 -10 43 0 -109 0 0 -12 22 36 9 18 5 23 105 -60 -12 47 50 -11 57 21 -13 46 24 -10 58 47 -108 0 0 -12 38 2 9 18 7 24 105 -59 -13 3 15 -12 12 49 -14 1 45 -11 14 18 -107 0 0 -12 53 13 9 18 9 25 104 -58 -13 18 24 -12 28 1 -14 16 51 -11 29 34 -106 0 0 -13 8 8 9 18 11 26 104 -57 -13 33 17 -12 42 58 -14 31 41 -11 44 34 -105 0 0 -13 22 46 9 18 13 27 104 -56 -13 47 55 -12 57 38 -14 46 14 -11 59 18 -104 0 0 -13 37 9 9 18 15 28 104 -55 -14 2 16 -13 12 2 -15 0 32 -12 13 46 -103 0 0 -13 51 15 9 18 17 29 103 -53 -14 16 21 -13 26 10 -15 14 33 -12 27 57 -102 0 0 -14 5 5 9 18 20 30 103 -52 -14 30 9 -13 40 1 -15 28 17 -12 41 52 -101 0 0 -14 18 38 9 18 22 31 103 -51 -14 43 40 -13 53 36 -15 41 45 -12 55 30 -100 0 0 -14 31 53 9 18 25 32 103 -50 -14 56 54 -14 6 53 -15 54 56 -13 8 51 - 99 0 0 -14 44 52 9 18 27 33 102 -49 -15 9 51 -14 19 53 -16 7 49 -13 21 54 - 98 0 0 -14 57 33 9 18 30 34 102 -48 -15 22 30 -14 32 35 -16 20 25 -13 34 40 - 97 0 0 -15 9 56 9 18 32 35 102 -47 -15 34 52 -14 45 0 -16 32 43 -13 47 8 - 96 0 0 -15 22 2 9 18 35 36 102 -46 -15 46 56 -14 57 7 -16 44 44 -13 59 19 - 95 0 0 -15 33 49 9 18 38 37 101 -45 -15 58 43 -15 8 56 -16 56 27 -14 11 12 - 94 0 0 -15 45 19 9 18 41 38 101 -44 -16 10 11 -15 20 27 -17 7 51 -14 22 46 - 93 0 0 -15 56 30 9 18 44 39 101 -44 -16 21 21 -15 31 40 -17 18 58 -14 34 2 - 92 0 0 -16 7 23 9 18 47 40 101 -43 -16 32 12 -15 42 35 -17 29 46 -14 45 0 - 91 0 0 -16 17 58 9 18 50 41 100 -42 -16 42 45 -15 53 10 -17 40 16 -14 55 39 - 90 0 0 -16 28 14 9 18 53 42 100 -41 -16 53 0 -16 3 28 -17 50 28 -15 5 59 - 89 0 0 -16 38 11 9 18 56 43 100 -40 -17 2 56 -16 13 26 -18 0 20 -15 16 1 - 88 0 0 -16 47 49 9 18 59 44 99 -39 -17 12 32 -16 23 6 -18 9 54 -15 25 43 - 87 0 0 -16 57 8 9 19 2 45 99 -38 -17 21 50 -16 32 26 -18 19 9 -15 35 7 - 86 0 0 -17 6 8 9 19 6 46 99 -37 -17 30 49 -16 41 27 -18 28 5 -15 44 11 - 85 0 0 -17 14 49 9 19 9 47 99 -36 -17 39 29 -16 50 10 -18 36 42 -15 52 56 - 84 0 0 -17 23 11 9 19 12 48 98 -35 -17 47 50 -16 58 32 -18 45 0 -16 1 21 - 83 0 0 -17 31 13 9 19 16 49 98 -34 -17 55 51 -17 6 36 -18 52 58 -16 9 27 - 82 0 0 -17 38 56 9 19 19 50 98 -33 -18 3 32 -17 14 20 -19 0 38 -16 17 14 - 81 0 0 -17 46 19 9 19 23 51 97 -32 -18 10 55 -17 21 44 -19 7 57 -16 24 41 - 80 0 0 -17 53 23 9 19 26 52 97 -31 -18 17 57 -17 28 49 -19 14 58 -16 31 48 - 79 0 0 -18 0 7 9 19 30 53 97 -30 -18 24 40 -17 35 34 -19 21 38 -16 38 35 - 78 0 0 -18 6 31 9 19 34 54 96 -29 -18 31 4 -17 41 59 -19 27 59 -16 45 2 - 77 0 0 -18 12 36 9 19 37 55 96 -28 -18 37 7 -17 48 4 -19 34 1 -16 51 10 - 76 0 0 -18 18 20 9 19 41 56 96 -27 -18 42 51 -17 53 50 -19 39 43 -16 56 57 - 75 0 0 -18 23 45 9 19 45 57 96 -26 -18 48 15 -17 59 15 -19 45 5 -17 2 24 - 74 0 0 -18 28 50 9 19 49 58 95 -25 -18 53 19 -18 4 20 -19 50 7 -17 7 31 - 73 0 0 -18 33 34 9 19 53 59 95 -24 -18 58 2 -18 9 6 -19 54 49 -17 12 18 - 72 0 0 -18 37 59 9 19 57 59 95 -23 -19 2 26 -18 13 31 -19 59 11 -17 16 45 - 71 0 0 -18 42 3 9 20 1 60 94 -22 -19 6 30 -18 17 36 -20 3 13 -17 20 52 - 70 0 0 -18 45 47 9 20 4 61 94 -21 -19 10 14 -18 21 21 -20 6 56 -17 24 38 - 69 0 0 -18 49 11 9 20 9 62 94 -20 -19 13 37 -18 24 45 -20 10 18 -17 28 4 - 68 0 0 -18 52 15 9 20 13 63 93 -19 -19 16 41 -18 27 50 -20 13 20 -17 31 9 - 67 0 0 -18 54 59 9 20 17 64 93 -18 -19 19 24 -18 30 34 -20 16 3 -17 33 54 - 66 0 0 -18 57 22 9 20 21 65 93 -17 -19 21 47 -18 32 57 -20 18 25 -17 36 18 - 65 0 0 -18 59 25 9 20 25 66 93 -16 -19 23 49 -18 35 1 -20 20 27 -17 38 22 - 64 0 0 -19 1 8 9 20 29 67 92 -15 -19 25 32 -18 36 43 -20 22 8 -17 40 6 - 63 0 0 -19 2 30 9 20 33 68 92 -14 -19 26 54 -18 38 6 -20 23 30 -17 41 29 - 62 0 0 -19 3 32 9 20 37 69 92 -13 -19 27 55 -18 39 8 -20 24 31 -17 42 31 - 61 0 0 -19 4 13 9 20 42 70 91 -12 -19 28 37 -18 39 50 -20 25 12 -17 43 13 - 60 0 0 -19 4 34 9 20 46 71 91 -11 -19 28 58 -18 40 11 -20 25 33 -17 43 34 - 59 0 0 -19 4 35 9 20 50 72 91 -10 -19 28 59 -18 40 12 -20 25 34 -17 43 35 - 58 0 0 -19 4 16 9 20 55 73 90 -10 -19 28 39 -18 39 52 -20 25 15 -17 43 15 - 57 0 0 -19 3 35 9 20 59 74 90 -9 -19 27 59 -18 39 12 -20 24 35 -17 42 35 - 56 0 0 -19 2 35 9 21 3 75 90 -8 -19 26 59 -18 38 11 -20 23 35 -17 41 34 - 55 0 0 -19 1 14 9 21 8 76 90 -7 -19 25 38 -18 36 50 -20 22 15 -17 40 12 - 54 0 0 -18 59 33 9 21 12 77 89 -6 -19 23 57 -18 35 8 -20 20 34 -17 38 30 - 53 0 0 -18 57 31 9 21 17 78 89 -5 -19 21 56 -18 33 6 -20 18 34 -17 36 27 - 52 0 0 -18 55 9 9 21 21 79 89 -4 -19 19 34 -18 30 44 -20 16 13 -17 34 4 - 51 0 0 -18 52 27 9 21 25 80 89 -3 -19 16 52 -18 28 1 -20 13 32 -17 31 20 - 50 0 0 -18 49 24 9 21 30 81 89 -2 -19 13 50 -18 24 58 -20 10 30 -17 28 16 - 49 0 0 -18 46 0 9 21 34 82 88 -1 -19 10 27 -18 21 34 -20 7 9 -17 24 51 Uncertainty in time = +/- 4 secs [Prediction of 2008 Feb 14.0] Data for the target star ------------------------ * name: 2UCAC 24957023 * constellation : Sagittarius * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 19 00 48.4710 DE: -18 14 06.543 * position source: mpos:UCAC2 pm:UCAC2 * standard error: RA,DE ["]: ( .071, .071 ) * V mag [mag]: 12.5 * B mag [mag]: 0.0 * Apparent position with proper motion RA(deg): 285.3240606878 DE(deg): -18.2254939752 * Equation of equinoxes (radians) : 0.000040697106570 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (17) Thetis approx. diameter [km]: 90 approx. diameter ["]: .061 distance from Earth [AU]: 2.02600 * orbital information: orbit source: Preston date of fit: 2008 Feb 13 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1632 number of rejected observations: 233 time covered by the observations: 1900 Oct 03 - 2007 Jun 26 1 sigma uncertainty ellipse (major, minor, PA): 0.008, 0.005, 91° remarks: * orbital elements for (17) Thetis : Mean anomaly = 356.27050382 deg Arg. of pericenter = 136.02292593 deg Long. of node = 125.60286257 deg Inclination = 5.58779593 deg Eccentricity = 0.13483218 Semimajor axis = 2.47045701 AU Perihelion dist = 2.13735991 AU Mag: H = 7.67, G = 0.15 Epoch of elements : MJD 54552.39100000 TDT (2008 Mar 27.391) ------ occelmnt file for Occult BEGIN ----------------------------------- 2008 Mar 27 17 Thetis 9h 22.2m UT 12.5 19 0 48.471-18 14 6.542UCAC 24957023 0.0 12.2 90 3.8 2.026 4.039 6.34 -40.5378 -18.237 40.77 2.81 9.3705 0.00072 0.00510 13.25508 1.46032 -0.00535 -0.00050 2000 355.6636032008 325.00000136.022926125.602863 5.5877960.13483218 2.4704570 2.1373599 7.8 5.00.15 RATE 2.5382720 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.071 0.071 90 2.16 0.071 0 54510.5020080327_957023 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2008 Feb 14, 19:55 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org