Electronic Telegram No. 5046 Central Bureau for Astronomical Telegrams Mailing address: Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network ARID METEORS 2021 P. Jenniskens, SETI Institute and NASA Ames Research Center; T. Cooper, Astronomical Society of Southern Africa; and D. Lauretta, University of Arizona, report that CAMS video-based meteoroid-orbit survey networks in New Zealand and Chile have detected a predicted meteor shower caused by earth- encountering debris ejected from comet 15P/Finlay during its perihelion passage in 1995. These are the first known meteors observed from comet 15P. The shower was added to the IAU Working List of Meteor Showers (no. 1130) under the name "Arids" because the meteors radiated from the southern constellation Ara (cf. website URL http://cams.seti.org/FDL/ for the dates 2021 Sept. 29 and 30). CAMS New Zealand (with stations operated by I. Crumpton, C. Duncan, and N. Frost, and the network coordinated by J. Baggaley of the University of Canterbury at Christchurch) triangulated nine Arids between 2021 Sept. 28d08h40m and 17h18m UTC, while CAMS Chile (with stations operated by J. Rojas, E. Jehin, and T. Abbott, and the network coordinated by S. Heathcote of AURA/Cerro Tololo) triangulated four Arids between Sept. 28d23h49m and 29d03h45m UTC. The outburst is ongoing. Other southern-hemisphere CAMS networks had poor weather. The meteors radiated from R.A. = 262.7 deg, Decl. = -57.8 deg (equinox J2000.0) with geocentric entry velocity 10.8 km/s from a direction with few sporadic meteors. The observed median orbital elements of the thirteen Arid meteors, centered on solar longitude 185.27 deg, are as follows: a = 3.53 AU, q = 1.0010 +/- 0.0004 AU, e = 0.717 +/- 0.042, i = 9.10 +/- 0.54 deg, Peri. = 356.1 +/- 1.01 deg, Node = 5.28 +/- 0.29 deg, Longitude of Perihelion = 1.50 +/- 1.00 deg (equinox J2000.0). The meteors were predicted to radiate from R.A. = 260.8 +/- 0.9 deg, Decl. = -57.4 +/- 0.5 deg, with geocentric velocity 10.807 km/s at peak time 2021 Sept. 29d08h35m UTC (cf. Vaubaillon et al. 2020, JIMO 48, 29; and references therein). Further meteor-shower activity from this comet is expected in the coming weeks. A second outburst from crossing the debris ejected in 2008 is predicted to be centered on 2021 Oct. 7d00h35m UT, followed by a third outburst from debris ejected in 2014 centered on 2021 Oct. 7d03h55m. J. S. Bruzzone, Astronomy Department, Faculty of Sciences, UdelaR, Igual, Montevideo; D. Janches, ITM Physics Laboratory, Goddard Space Flight Center, NASA; R. Weryk, Department of Physics and Astronomy, University of Western Ontario; and J. L. Hormaechea, Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de, La Plata, and Estacion Astronomica Rio Grande, Tierra del Fuego, Argentina, report the detection of a sudden outburst of meteor activity presumably associated with comet 15P using the "Southern Argentina Agile MEteor Radar Orbital System" (SAAMER-OS) centered at Sept. 29d03h32m UTC, corresponding to solar longitude 185.92 degrees, and lasting an estimated three hours. SAAMER-OS is a 64-kW (peak) single-element all-sky backscatter radar operating at 32 MHz and located in Tierra del Fuego; the system comprises one main station hosting the transmitting antenna and receiver interferometer plus four remote receiving stations for meteor-orbit determination. The sun-centered ecliptic radiant of the current outburst on Sept. 29 is located at (sun-centered) ecliptic longitude 77.658 deg, latitude -34.5 deg (equinox J2000.0), with meteor velocities of 11 km/s (not corrected for meteor deceleration), with over 100 meteors identified with a strong 8-sigma detection, having average orbital elements a = 3.551 AU, e = 0.7183, i = 9.273 deg, Peri. = 355.55 deg, Node = 6.285 deg, and M = 0.506 deg (equinox J2000.0). Multiple meteor outbursts were predicted in 2021 (cf. Ye et al. 2015, Ap.J. 814, 79; Vaubaillon et al. 2020, J. Int. Meteor Organization, via HAL archive online no. 03017579) for observers at high southern latitudes, with expected entry to the earth's upper atmosphere with a geocentric velocity of 10.8 km/s; the outburst reported here is < 0.01 degree from the first predicted event of Vaubaillon et al. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2021 CBAT 2021 October 1 (CBET 5046) Daniel W. E. Green