Abstract :
[en] P. Jenniskens, SETI Institute and NASA Ames Research Center, reports that southern-hemisphere "Cameras for Allsky Meteor Surveillance" (CAMS) networks detected an unusually brief meteor shower on 2021 Mar. 22 (cf. website URL http://cams.seti.org/FDL/). Called the zeta Pavonid meteors (IAU shower number 835), this shower's activity profile had a duration of only 0.46 degrees (full-width-at-half-maximum) centered on 1.41 degrees solar longitude. The shower was detected between Mar. 21d19h and 22d11h UTC, corresponding to solar longitudes 1.11-1.73 degrees (equinox J2000.0). Three zeta Pavonid meteors were triangulated by CAMS Australia (M. Towner, Curtin University, with support of L. Toms and C. Reford), two by CAMS South Africa (T. Cooper, Astronomical Society of Southern Africa; and P. Mey, South African Radio Astronomy Observatory), six by CAMS Namibia (T. Hanke, E. Fahl, and R. van Wyk, involved with the H.E.S.S. Collaboration), and six by CAMS Chile (S. Heathcote and T. Abbott, AURA/Cerro Tololo; and E. Jehin, University of Liege). No zeta Pavonids were triangulated the night before or after. Orbital elements are those of an unknown long-period comet with semi-major axis close to the parabolic limit. The median orbit is slightly hyperbolic, with orbital elements being a strong function of the measured entry speed. The best-fit parabolic orbit has meteors that radiate from geocentric R.A. = 279.5 +/- 1.8 deg, Decl. = -71.1 +/- 1.0 deg (equinox J2000.0), with geocentric velocities 55.6 +/- 1.6 km/s, with corresponding orbital elements q = 0.993 +/- 0.002 AU, e = 1.0, i = 99.6 +/- 0.5 deg, Peri. = 353.6 +/- 1.7 deg, Node = 181.4 +/- 0.2 deg (equinox J2000.0). It is unclear at present if the activity itself is unusual or returns annually. The shower was also detected by the same networks in 2020, when 12 meteors were triangulated, centered on 1.25 degrees solar longitude. The shower was first detected in 2016, when CAMS New Zealand triangulated five meteors centered on 1.15 degrees solar longitude (cf. Jenniskens et al. 2018, Planetary Space Sci. 154, 21). Weather prevented observations during 2017-2019.
