IOTA/IOTA-ES occultation update for (971) Alsatia / UCAC4 587-031418 event on 2020 Dec 19, 00:21 UT Visible from Africa, South America Summary ------- On 2020 Dec 19 UT, the 62.8 km diameter asteroid (971) Alsatia will occult a 11.7 mag star in the constellation Gemini for observers along a path across Africa, South America. In the case of an occultation, the combined light of the asteroid and the star will drop by 1.40 mag to 12.70 mag (the magnitude of the asteroid) for at most 6.1 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, astrometry for the asteroid kindly provided by Bill Owen, astrometry for the asteroid kindly provided by the IAU Minor Planet Center. This work has made use of data from the European Space Agency (ESA) mission Gaia (http://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, http://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. The event at a glimpse ---------------------- * Rank: 95 * date and approx. time of event: 2020 Dec 19, 00:13 - 2020 Dec 19, 00:29 * geocentric midpoint of event [JD]: 2459202.51485000 * magnitude of target star: 11.65 * magnitude drop [mag]: 1.40 * estimated maximum duration [s]: 6.1 * Moon: 22 % sunlit, 135° distance * Sun: 169° distance * rough path description: Africa, South America The occultation path -------------------- * approximate projected width [km]: 81 * 1 sigma uncertainty interval [path widths]: +/- 0.44 * 1 sigma uncertainty interval [seconds]: +/- 2.7 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- 0.040, +/- 0.017) * 1 sigma uncertainty ellipse (major, minor, PA): (0.041", 0.016", 80°) * approx speed of asteroid's shadow [km/s]: 10.3595 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of UCAC4 587-031418 by 971 Alsatia on 2020 Dec 19 Centre Star Star Sun Path Limits Error Limits Alt E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4 Crn o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " Longitude Longitude Longitude Longitude 39 37 57 -58 0 0 0 13 26.0 1 332 -1 40 25 20 38 50 32 41 7 16 38 8 32 .... 38 37 0 -57 0 0 0 13 26.3 2 333 -2 39 23 10 37 50 48 40 4 0 37 9 52 0.44 37 37 24 -56 0 0 0 13 26.9 3 333 -3 38 22 25 36 52 19 39 2 15 36 12 22 0.60 36 38 57 -55 0 0 0 13 27.8 4 334 -4 37 22 56 35 54 56 38 1 50 35 15 54 0.66 35 41 33 -54 0 0 0 13 29.1 5 335 -5 36 24 33 34 58 29 37 2 35 34 20 18 0.70 34 45 3 -53 0 0 0 13 30.6 6 336 -7 35 27 9 34 2 53 36 4 22 33 25 29 0.73 33 49 19 -52 0 0 0 13 32.5 7 337 -8 34 30 35 33 8 0 35 7 4 32 31 20 0.75 32 54 17 -51 0 0 0 13 34.7 9 337 -9 33 34 46 32 13 44 34 10 32 31 37 45 0.76 31 59 49 -50 0 0 0 13 37.2 10 338 -10 32 39 34 31 19 59 33 14 42 30 44 39 0.77 31 5 51 -49 0 0 0 13 40.0 11 339 -11 31 44 56 30 26 42 32 19 27 29 51 57 0.78 30 12 18 -48 0 0 0 13 43.2 12 339 -12 30 50 44 29 33 46 31 24 42 28 59 34 0.78 29 19 4 -47 0 0 0 13 46.6 13 340 -14 29 56 56 28 41 7 30 30 22 28 7 26 0.79 28 26 7 -46 0 0 0 13 50.4 14 341 -15 29 3 25 27 48 42 29 36 23 27 15 30 0.79 27 33 21 -45 0 0 0 13 54.5 15 341 -16 28 10 9 26 56 26 28 42 40 26 23 40 0.80 26 40 42 -44 0 0 0 13 59.0 17 342 -17 27 17 3 26 4 16 27 49 8 25 31 55 0.80 25 48 9 -43 0 0 0 14 3.8 18 343 -18 26 24 3 25 12 8 26 55 45 24 40 9 0.80 24 55 36 -42 0 0 0 14 8.9 19 343 -19 25 31 6 24 19 59 26 2 27 23 48 21 0.81 24 3 0 -41 0 0 0 14 14.3 20 344 -21 24 38 8 23 27 45 25 9 10 22 56 26 0.81 23 10 19 -40 0 0 0 14 20.1 21 345 -22 23 45 7 22 35 24 24 15 50 22 4 23 0.81 22 17 29 -39 0 0 0 14 26.1 22 346 -23 22 51 58 21 42 52 23 22 25 21 12 7 0.81 21 24 27 -38 0 0 0 14 32.6 23 346 -24 21 58 40 20 50 6 22 28 51 20 19 36 0.81 20 31 10 -37 0 0 0 14 39.3 25 347 -25 21 5 7 19 57 4 21 35 6 19 26 46 0.81 19 37 34 -36 0 0 0 14 46.4 26 348 -27 20 11 19 19 3 42 20 41 5 18 33 36 0.82 18 43 38 -35 0 0 0 14 53.9 27 348 -28 19 17 11 18 9 58 19 46 46 17 40 2 0.82 17 49 18 -34 0 0 0 15 1.7 28 349 -29 18 22 41 17 15 48 18 52 7 16 46 0 0.82 16 54 31 -33 0 0 0 15 9.8 29 350 -30 17 27 45 16 21 9 17 57 3 15 51 29 0.82 15 59 14 -32 0 0 0 15 18.3 30 351 -31 16 32 20 15 25 58 17 1 32 14 56 24 0.82 15 3 23 -31 0 0 0 15 27.1 31 352 -33 15 36 24 14 30 13 16 5 30 14 0 44 0.82 14 6 56 -30 0 0 0 15 36.3 32 352 -34 14 39 53 13 33 50 15 8 55 13 4 23 0.82 13 9 49 -29 0 0 0 15 45.9 33 353 -35 13 42 43 12 36 45 14 11 43 12 7 20 0.82 12 11 59 -28 0 0 0 15 55.8 35 354 -36 12 44 52 11 38 55 13 13 51 11 9 30 0.82 11 13 21 -27 0 0 0 16 6.0 36 355 -37 11 46 15 10 40 17 12 15 14 10 10 51 0.82 10 13 53 -26 0 0 0 16 16.7 37 356 -39 10 46 49 9 40 46 11 15 50 9 11 17 0.82 9 13 30 -25 0 0 0 16 27.7 38 357 -40 9 46 31 8 40 18 10 15 35 8 10 45 0.82 8 12 8 -24 0 0 0 16 39.0 39 358 -41 8 45 14 7 38 50 9 14 23 7 9 11 0.82 7 9 42 -23 0 0 0 16 50.8 40 359 -42 7 42 56 6 36 16 8 12 12 6 6 29 0.82 6 6 8 -22 0 0 0 17 3.0 41 1 -43 6 39 32 5 32 31 7 8 55 5 2 35 0.82 5 1 20 -21 0 0 0 17 15.5 42 2 -45 5 34 56 4 27 31 6 4 29 3 57 22 0.82 3 55 13 -20 0 0 0 17 28.5 43 3 -46 4 29 2 3 21 9 4 58 47 2 50 47 0.82 2 47 39 -19 0 0 0 17 41.9 44 4 -47 3 21 45 2 13 18 3 51 44 1 42 40 0.82 1 38 34 -18 0 0 0 17 55.7 45 6 -48 2 12 59 1 3 53 2 43 14 0 32 56 0.81 0 27 48 -17 0 0 0 18 9.9 45 7 -49 1 2 35 - 0 7 16 1 33 9 - 0 38 33 0.81 - 0 44 45 -16 0 0 0 18 24.6 46 9 -50 - 0 9 34 - 1 20 15 0 21 21 - 1 51 57 0.81 - 1 59 16 -15 0 0 0 18 39.7 47 11 -52 - 1 23 36 - 2 35 16 - 0 52 17 - 3 7 25 0.81 - 3 15 55 -14 0 0 0 18 55.3 48 12 -53 - 2 39 43 - 3 52 28 - 2 7 56 - 4 25 8 0.81 - 4 34 53 -13 0 0 0 19 11.5 48 14 -54 - 3 58 5 - 5 12 5 - 3 25 47 - 5 45 20 0.81 - 5 56 24 -12 0 0 0 19 28.1 49 16 -55 - 5 18 54 - 6 34 19 - 4 46 2 - 7 8 14 0.81 - 7 20 44 -11 0 0 0 19 45.3 50 18 -56 - 6 42 26 - 7 59 28 - 6 8 54 - 8 34 9 0.81 - 8 48 9 -10 0 0 0 20 3.1 50 20 -57 - 8 8 58 - 9 27 49 - 7 34 40 - 10 3 22 0.81 - 10 19 1 - 9 0 0 0 20 21.5 50 23 -57 - 9 38 49 - 10 59 45 - 9 3 39 - 11 36 18 0.81 - 11 53 44 - 8 0 0 0 20 40.5 51 25 -58 - 11 12 22 - 12 35 43 - 10 36 13 - 13 13 26 0.81 - 13 32 50 - 7 0 0 0 21 0.3 51 28 -59 - 12 50 6 - 14 16 15 - 12 12 48 - 14 55 18 0.81 - 15 16 53 - 6 0 0 0 21 20.9 51 30 -59 - 14 32 34 - 16 2 0 - 13 53 57 - 16 42 38 0.81 - 17 6 41 - 5 0 0 0 21 42.3 51 33 -60 - 16 20 30 - 17 53 48 - 15 40 19 - 18 36 19 0.81 - 19 3 12 - 4 0 0 0 22 4.8 51 35 -60 - 18 14 46 - 19 52 43 - 17 32 43 - 20 37 32 0.81 - 21 7 43 - 3 0 0 0 22 28.4 50 38 -60 - 20 16 32 - 22 0 12 - 19 32 14 - 22 47 51 0.81 Latitude Latitude Latitude Latitude - 23 0 0 - 2 9 29 0 22 49.3 50 41 -60 - 1 45 45 - 2 33 22 - 1 24 51 - 2 54 38 0.81 - 24 0 0 - 1 43 53 0 23 0.3 50 42 -60 - 1 20 17 - 2 7 37 - 0 59 31 - 2 28 46 0.81 - 25 0 0 - 1 19 14 0 23 11.2 49 43 -59 - 0 55 46 - 1 42 50 - 0 35 6 - 2 3 51 0.81 - 26 0 0 - 0 55 31 0 23 21.9 49 44 -59 - 0 32 11 - 1 19 0 - 0 11 38 - 1 39 54 0.81 - 27 0 0 - 0 32 46 0 23 32.6 49 45 -59 - 0 9 33 - 0 56 6 0 10 54 - 1 16 53 0.81 - 28 0 0 - 0 10 56 0 23 43.1 48 46 -59 0 12 10 - 0 34 9 0 32 30 - 0 54 50 0.81 - 29 0 0 0 9 58 0 23 53.6 48 47 -58 0 32 57 - 0 13 9 0 53 12 - 0 33 43 0.81 - 30 0 0 0 29 57 0 24 3.9 47 48 -58 0 52 50 0 6 57 1 12 59 - 0 13 32 0.81 - 31 0 0 0 49 1 0 24 14.0 47 49 -57 1 11 47 0 26 6 1 31 51 0 5 43 0.81 - 32 0 0 1 7 10 0 24 24.0 46 50 -57 1 29 51 0 44 21 1 49 50 0 24 3 0.81 - 33 0 0 1 24 24 0 24 34.0 46 51 -56 1 47 0 1 1 41 2 6 54 0 41 28 0.81 - 34 0 0 1 40 45 0 24 43.7 45 52 -56 2 3 16 1 18 7 2 23 5 0 57 58 0.81 - 35 0 0 1 56 12 0 24 53.4 44 52 -55 2 18 38 1 33 39 2 38 23 1 13 34 0.81 - 36 0 0 2 10 45 0 25 2.9 44 53 -55 2 33 6 1 48 16 2 52 48 1 28 16 0.81 - 37 0 0 2 24 25 0 25 12.2 43 54 -54 2 46 42 2 2 1 3 6 20 1 42 4 0.81 - 38 0 0 2 37 12 0 25 21.4 42 54 -54 2 59 25 2 14 52 3 19 0 1 54 59 0.81 - 39 0 0 2 49 6 0 25 30.5 42 55 -53 3 11 16 2 26 49 3 30 48 2 7 0 0.81 - 40 0 0 3 0 8 0 25 39.5 41 56 -52 3 22 14 2 37 54 3 41 43 2 18 8 0.81 - 41 0 0 3 10 17 0 25 48.3 40 56 -52 3 32 20 2 48 6 3 51 47 2 28 23 0.81 - 42 0 0 3 19 34 0 25 56.9 40 57 -51 3 41 35 2 57 26 4 0 58 2 37 45 0.81 - 43 0 0 3 27 58 0 26 5.4 39 57 -50 3 49 57 3 5 53 4 9 19 2 46 14 0.81 - 44 0 0 3 35 31 0 26 13.8 38 58 -49 3 57 27 3 13 28 4 16 47 2 53 51 0.81 - 45 0 0 3 42 12 0 26 22.0 37 58 -49 4 4 6 3 20 10 4 23 25 3 0 35 0.81 - 46 0 0 3 48 1 0 26 30.1 37 58 -48 4 9 54 3 26 1 4 29 10 3 6 26 0.81 - 47 0 0 3 52 57 0 26 38.0 36 59 -47 4 14 49 3 30 59 4 34 5 3 11 26 0.81 - 48 0 0 3 57 3 0 26 45.8 35 59 -46 4 18 53 3 35 5 4 38 8 3 15 33 0.81 - 49 0 0 4 0 16 0 26 53.4 34 59 -45 4 22 6 3 38 19 4 41 20 3 18 47 0.81 - 50 0 0 4 2 38 0 27 0.8 33 60 -45 4 24 27 3 40 41 4 43 41 3 21 10 0.81 - 51 0 0 4 4 7 0 27 8.1 33 60 -44 4 25 57 3 42 11 4 45 11 3 22 40 0.82 - 52 0 0 4 4 45 0 27 15.3 32 60 -43 4 26 35 3 42 48 4 45 49 3 23 17 0.82 - 53 0 0 4 4 31 0 27 22.2 31 60 -42 4 26 21 3 42 34 4 45 35 3 23 2 0.82 - 54 0 0 4 3 24 0 27 29.0 30 61 -41 4 25 15 3 41 26 4 44 30 3 21 54 0.82 - 55 0 0 4 1 25 0 27 35.7 29 61 -40 4 23 17 3 39 27 4 42 34 3 19 53 0.82 - 56 0 0 3 58 34 0 27 42.2 28 61 -39 4 20 28 3 36 34 4 39 45 3 16 59 0.82 - 57 0 0 3 54 50 0 27 48.5 28 61 -39 4 16 45 3 32 49 4 36 4 3 13 12 0.82 - 58 0 0 3 50 14 0 27 54.6 27 61 -38 4 12 11 3 28 10 4 31 31 3 8 32 0.82 - 59 0 0 3 44 44 0 28 0.6 26 61 -37 4 6 43 3 22 38 4 26 6 3 2 58 0.82 - 60 0 0 3 38 21 0 28 6.3 25 61 -36 4 0 23 3 16 12 4 19 47 2 56 30 0.82 - 61 0 0 3 31 4 0 28 11.9 24 62 -35 3 53 9 3 8 53 4 12 36 2 49 8 0.83 - 62 0 0 3 22 53 0 28 17.4 23 62 -34 3 45 1 3 0 39 4 4 31 2 40 51 0.83 - 63 0 0 3 13 48 0 28 22.6 22 62 -33 3 36 0 2 51 30 3 55 32 2 31 39 0.83 - 64 0 0 3 3 49 0 28 27.6 21 62 -32 3 26 4 2 41 26 3 45 40 2 21 32 0.83 - 65 0 0 2 52 54 0 28 32.5 20 62 -31 3 15 13 2 30 27 3 34 53 2 10 29 0.83 - 66 0 0 2 41 4 0 28 37.1 19 62 -30 3 3 27 2 18 33 3 23 11 1 58 30 0.83 - 67 0 0 2 28 17 0 28 41.6 18 62 -29 2 50 46 2 5 42 3 10 34 1 45 35 0.84 - 68 0 0 2 14 35 0 28 45.8 17 62 -28 2 37 8 1 51 54 2 57 1 1 31 42 0.84 - 69 0 0 1 59 55 0 28 49.9 16 62 -27 2 22 34 1 37 9 2 42 31 1 16 52 0.84 - 70 0 0 1 44 18 0 28 53.7 15 62 -26 2 7 3 1 21 26 2 27 5 1 1 4 0.84 - 71 0 0 1 27 43 0 28 57.3 14 62 -25 1 50 34 1 4 44 2 10 42 0 44 17 0.84 - 72 0 0 1 10 10 0 29 0.7 13 62 -24 1 33 7 0 47 4 1 53 21 0 26 30 0.85 - 73 0 0 0 51 37 0 29 3.9 12 62 -23 1 14 42 0 28 24 1 35 1 0 7 44 0.85 - 74 0 0 0 32 4 0 29 6.8 11 62 -22 0 55 16 0 8 44 1 15 42 - 0 12 3 0.85 - 75 0 0 0 11 31 0 29 9.5 10 62 -21 0 34 51 - 0 11 57 0 55 23 - 0 32 51 0.86 - 76 0 0 - 0 10 3 0 29 12.0 9 62 -20 0 13 25 - 0 33 40 0 34 5 - 0 54 41 0.86 - 77 0 0 - 0 32 39 0 29 14.2 8 62 -19 - 0 9 3 - 0 56 24 0 11 44 - 1 17 34 0.86 - 78 0 0 - 0 56 18 0 29 16.1 7 62 -18 - 0 32 32 - 1 20 12 - 0 11 37 - 1 41 30 0.87 - 79 0 0 - 1 21 0 0 29 17.8 6 62 -17 - 0 57 5 - 1 45 4 - 0 36 2 - 2 6 30 0.88 - 80 0 0 - 1 46 46 0 29 19.2 5 62 -16 - 1 22 41 - 2 11 0 - 1 1 29 - 2 32 35 0.89 - 81 0 0 - 2 13 37 0 29 20.4 4 62 -15 - 1 49 21 - 2 38 1 - 1 28 1 - 2 59 46 0.91 - 82 0 0 - 2 41 33 0 29 21.3 3 62 -14 - 2 17 7 - 3 6 9 - 1 55 37 - 3 28 4 0.94 - 83 0 0 - 3 10 36 0 29 21.9 2 62 -12 - 2 45 59 - 3 35 24 .. .. .. - 3 57 29 1.01 - 84 0 0 - 3 40 47 0 29 22.1 1 63 -11 - 3 15 58 - 4 5 46 .. .. .. - 4 28 2 1.39 Uncertainty in time = +/- 4 secs Prediction of 2020 Oct 28.0 Data for the target star ------------------------ * name: UCAC4 587-031418 * constellation : Gemini * BCRS position with proper motion to date of event [h,m,s ; °,',"] RA: 06 34 18.1177 DE: +27 22 48.236 * GCRS Astrometric position with proper motion and parallax to date of event [h,m,s ; °,',"] RA: 06 34 18.1177 DE: +27 22 48.236 * position source: Gaia DR2 * standard error: RA,DE [mas]: (0.400,0.400) * V mag [mag]: 11.7 * Diameter [mas]: 0.00 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (971) Alsatia asteroid class: approx. diameter [km]: 63 approx. diameter ["]: 0.070 distance from Earth [AU]: 1.23770 asteroid position offset in RA [mas]: 0 asteroid position offset in DE [mas]: 0 * orbital information: orbit source: Preston date of fit: 2020 Oct 28 source of used astrometry: MPC, FASTT, TMO number of used observations: 2460 number of rejected observations: 10 time covered by the observations: 1961 Jan 12 - 2020 Oct 21 1 sigma uncertainty ellipse (major, minor, PA): 0.041", 0.016", 79.9° remarks: * orbital elements for (971)Alsatia : Mean anomaly = 2.33399343 deg Arg. of pericenter = 6.53480388 deg Long. of node = 83.49597648 deg Inclination = 13.79166498 deg Eccentricity = 0.16275561 Semimajor axis = 2.64044481 AU Perihelion dist = 2.21069761 AU Mag: H = 10.10, G = 0.15 Epoch of elements : MJD 59202.01500000 TDT (2020 Dec 19.0150) ------ occelmnt file for Occult BEGIN ----------------------------------- Preston2020Oct28,6.1,2020,12,19,0.3564,-0.35601,-0.51745,-4.81794,3.31312,-0.00102,-0.00034,0.00000,0.00000 5.4926,27.3625,173.93,-23.41 UCAC4 587-031418,6.57169935,27.3800656,0.00,11.65,0.00,0.0,0,,6.59367088,27.3625154 971,Alsatia,12.70,62.8,1.2377,0,0,-2.570,23.54,,3.4 0,2.1008,2020,12,18,6.5348,83.4960,13.7917,0.16276,2.64044,2.21070,10.10,5.0,0.15 1.443,0.0410,0.0160,80,0.0310,Known errors 20201219_031418,59150.00 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2020 Oct 28, 20:44 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 stevepr@acm.org