Abstract :
[en] P. Jenniskens, SETI Institute and NASA Ames Research Center, reports that southern-hemisphere "Cameras for Allsky Meteor Surveillance" (CAMS) networks detected strong activity from the Delta Mensid meteor stream (IAU shower 130) in the brief interval between Mar. 12d10h and 13d06h UTC (corresponding to solar longitudes 351.77-352.57 degrees, equinox J2000.0). Outside this interval, the shower rate was only around 1 meteor per day from what may be an annual shower -- which is ongoing, based on 2020 observations (cf. website URL http://cams.seti.org/FDL/ for the date of 2021 Mar. 13). CAMS Namibia (T. Hanke, E. Fahl, and R. van Wyk, with the H.E.S.S. Collaboration), CAMS Chile (S. Heathcote and T. Abbott, AURA/Cerro Tololo; and E. Jehin, University of Liege), CAMS Australia (M. Towner, Curtin University, with support of L. Toms and C. Reford), CAMS New Zealand (J. Baggaley, University of Canterbury; and N. Frost, Mount John Observatory, with support from I. Crumpton and C. and L. Duncan), and CAMS South Africa (T. Cooper, Astronomical Society of Southern Africa; and P. Mey, South African Radio Astronomy Observatory) triangulated a total of twenty-nine Delta Mensid meteors. The meteors radiated from a median geocentric radiant at R.A. = 62.2 +/- 4.9 deg, Decl. = -77.4 +/- 1.1 degrees (equinox J2000.0) and geocentric velocity 30.9 +/- 1.6 km/s. Median orbital elements are those of a Jupiter-family comet and are as follows: q = 0.977 +/- 0.004 AU, semi-major axis approximately 3.0 AU, e = 0.679 +/- 0.094, i = 51.1 +/- 2.0 degrees, Peri. = 343.8 +/- 2.5 degrees, Node = 172.26 +/- 0.22 deg (equinox J2000.0), in good agreement with 2020 results (cf. CBET 4772). The shower peaked at solar longitude 352.26 +/- 0.05 degrees with a full- width-at-half-maximum of about 0.5 degrees in solar longitude. In 2020, the shower peaked at solar longitude 352.40 +/- 0.08 degrees (cf. CBET 4772) and had strong activity also during Mar. 20-22.
