IOTA/IOTA-ES occultation update for 2013 KY18 / UCAC4 329-121097 event on 2023 Jul 23, 11:10 UT Visible from Summary ------- On 2023 Jul 23 UT, the 144.5 km diameter asteroid 2013 KY18 will occult a 14.8 mag star in the constellation Sagittarius for observers along a path across . In the case of an occultation, the combined light of the asteroid and the star will drop by 6.78 mag to 21.56 mag (the magnitude of the asteroid) for at most 7.250 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: 3 * date and approx. time of event: predicted path center does not land on Earth. * geocentric midpoint of event [JD]: 2460148.96281100 * magnitude of target star: 14.78 * magnitude drop [mag]: 6.78 * estimated maximum duration [s]: 7.250 * Moon: 27 % sunlit, 87° distance * Sun: 150° distance * rough path description: The occultation path -------------------- * approximate projected width [km]: 145 * 1 sigma uncertainty interval [path widths]: +/- 20.86 * 1 sigma uncertainty interval [seconds]: +/- 450.1 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- 0.436, +/- 0.142) * 1 sigma uncertainty ellipse (major, minor, PA): (0.439", 0.133", 97°) * approx speed of asteroid's shadow [km/s]: 19.9270 * website for maps: http://www.asteroidoccultation.com Path Coordinates: No Lat/Long file for this path. Data for the target star ------------------------ * name: UCAC4 329-121097 * constellation : Sagittarius * BCRS position with proper motion to date of event [h,m,s ; °,',"] RA: 18 01 44.2473 DE: -24 16 31.781 * GCRS Astrometric position with proper motion and parallax to date of event [h,m,s ; °,',"] RA: 18 01 44.2473 DE: -24 16 31.781 * position source: Gaia DR3 * standard error: RA,DE [mas]: (0.200,0.200) * V mag [mag]: 14.8 * Diameter [mas]: 0.00 * remarks: Data for the minor planet ------------------------- * general information: (number) name: 2013 KY18 asteroid class: approx. diameter [km]: 145 approx. diameter ["]: 0.007 distance from Earth [AU]: 28.45710 asteroid position offset in RA [mas]: 0 asteroid position offset in DE [mas]: 0 * orbital information: orbit source: JPL#7 date of fit: 2022 Mar 09 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): 0.439", 0.133", 96.9° remarks: * orbital elements for 2013 KY18 : Mean anomaly = 289.2359719488 deg Arg. of pericenter = 271.7091483262 deg Long. of node = 84.4183660772 deg Inclination = 6.6665158459 deg Eccentricity = 0.1235108983 Semimajor axis = 30.1400320688 AU Perihelion dist = 26.4174096339 AU Mag: H = 6.80, G = 0.15 Epoch of elements : MJD 60148.46583333 TDT (2023 Jul 23.4658) ------ occelmnt file for Occult BEGIN ----------------------------------- JPL#72022Mar09,7.25,2023,7,23,11.107464,-0.027727,1.028528,-11.243265,-0.302331,0.002918,0.000089,0.000001,0.000000 163.2544,-24.2763,15.03,20.07,False UCAC4 329-121097,18.02895757,-24.2754946,0.00,14.78,0.00,0.0,0,,18.05322920,-24.2762780,6.78,0.00,0,0,0 0,2013 KY18,21.56,144.5,28.4571,0,0,-0.254,-0.09,,14.5 0,289.2332,2023,7,23,271.7091,84.4184,6.6665,0.12351,30.14003,26.41741,6.80,5.0,0.15 21.859,0.4387,0.1327,97,0.1460,Known errors,-1.00,-1,-1,-1 20230723_121097,59745.18 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2022 Jun 15, 04:26 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 stevepr@acm.org