IOTA/IOTA-ES occultation update for 2015 GC56 / UCAC4 358-069123 event on 2023 Dec 30, 12:00 UT Visible from Summary ------- On 2023 Dec 30 UT, the 109.144 km diameter asteroid 2015 GC56 will occult a 15.0 mag star in the constellation Virgo for observers along a path across . In the case of an occultation, the combined light of the asteroid and the star will drop by 8.41 mag to 23.38 mag (the magnitude of the asteroid) for at most 5.250 seconds. This update is based on, 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: 0 * date and approx. time of event: predicted path center does not land on Earth. * geocentric midpoint of event [JD]: 2460309.01940817 * magnitude of target star: 14.97 * magnitude drop [mag]: 8.41 * estimated maximum duration [s]: 5.250 * Moon: 89 % sunlit, 81° distance * Sun: 60° distance * rough path description: The occultation path -------------------- * approximate projected width [km]: 109 * 1 sigma uncertainty interval [path widths]: +/- 172.97 * 1 sigma uncertainty interval [seconds]: +/- 1729.5 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- 1.093, +/- 0.994) * 1 sigma uncertainty ellipse (major, minor, PA): (1.321", 0.662", 130°) * approx speed of asteroid's shadow [km/s]: 20.7953 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Path center does not land on earth. Data for the target star ------------------------ * name: UCAC4 358-069123 * constellation : Virgo * BCRS position with proper motion to date of event [h,m,s ; °,',"] RA: 14 16 41.8499 DE: -18 26 59.892 * GCRS Astrometric position with proper motion and parallax to date of event [h,m,s ; °,',"] RA: 14 16 41.8501 DE: -18 26 59.893 * position source: Gaia DR3 * standard error: RA,DE [mas]: (0.300,0.200) * V mag [mag]: 15.0 * Diameter [mas]: 0.00 * remarks: Data for the minor planet ------------------------- * general information: (number) name: 2015 GC56 asteroid class: Centaur approx. diameter [km]: 109 approx. diameter ["]: 0.004 distance from Earth [AU]: 38.19160 asteroid position offset in RA [mas]: 0 asteroid position offset in DE [mas]: 0 * orbital information: orbit source: JPL#3 date of fit: 2022 Jun 15 source of used astrometry: MPC, JPL number of used observations: 0 number of rejected observations: 0 time covered by the observations: 1800 Jan 01 - 1800 Jan 01 1 sigma uncertainty ellipse (major, minor, PA): 1.321", 0.662", 130.439° remarks: * orbital elements for 2015 GC56 : Mean anomaly = 0.9911860737 deg Arg. of pericenter = 186.7550207255 deg Long. of node = 28.1248221408 deg Inclination = 27.9121113270 deg Eccentricity = 0.4594230808 Semimajor axis = 69.7340412381 AU Perihelion dist = 37.6966131742 AU Mag: H = 7.41, G = 0.15 Epoch of elements : MJD 60308.50062500 TDT (2023 Dec 30.5006) ------ occelmnt file for Occult BEGIN ----------------------------------- JPL#32022Jun15,5.25,2023,12,30,12.465796,1.403018,2.237495,9.905909,-6.296032,-0.005155,0.001534,-0.000001,0.000000 -71.1767,-18.5597,-6.39,-23.16,False UCAC4 358-069123,14.27829163,-18.4499700,0.00,14.97,0.00,0.0,0,,14.30014698,-18.5597128,8.41,0.00,0,0,0 0,2015 GC56,23.38,109.144,38.1916,0,0,0.162,-1.46,,10.9,0 0,0.9903,2023,12,30,186.7550,28.1248,27.9121,0.45942,69.73404,37.69661,7.41,5.0,0.15 173.879,1.3207,0.6623,130,1.4774,Known errors,-1.00,0,-1,-1 20231230_069123,60261.88 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2023 Nov 13, 21:02 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 stevepr@acm.org