Abstract :
[en] P. Jenniskens, SETI Institute and NASA Ames Research Center, reports that the iota Centaurid meteors (IAU shower no. 919), showed stronger than usual activity during 2024 Jan. 21-26 (corresponding to solar longitudes 301.0 to 306.0 deg; equinox J2000.0; see the map at URL http://cams.seti.org/FDL/ for dates of Jan. 23 and 24). Forty-eight iota Centaurids were triangulated by CAMS New Zealand, as coordinated by J. Baggaley (University of Canterbury) and J. Scott (University of Otago); 34 shower meteors by CAMS Australia, via H. Devillepoix (Curtin University) and D. Rollinson; 16 shower meteors by CAMS Chile, via S. Heathcote and T. Abbott (NOIRLAB/Cerro Tololo) and E. Jehin (University of Liege), 2 shower meteors by a mostly clouded CAMS Namibia, via T. Hanke (H.E.S.S. Collaboration), and 1 shower meteor by the northern- hemisphere United Arab Emirates Astronomical Camera Network, via M. Odeh (International Astronomical Center). The annual ratio of triangulated iota Centaurids to all sporadic meteors for these networks was, starting in 2020: 0.0037 +/- 0.0009, 0.0038 +/- 0.0010, 0.0018 +/- 0.0007, 0.0034 +/- 0.0009, and 0.0145 +/- 0.0015. Rates were above normal, peaking at 302.4 +/- 0.1 deg, with a full-width-at-half maximum duration of about 1.6 deg. The meteors radiated from a geocentric radiant at R.A. = 200.6 deg, Decl. = -40.3 deg, with geocentric velocity 63.7 km/s. Median orbital elements were a = 4.7 AU, q = 0.979 +/- 0.005 AU, e = 0.790 +/- 0.086, i = 129.4 +/- 1.5 deg, Peri = 350.8 +/- 3.4 deg, Node = 122.4 +/- 1.7 deg (equinox J2000.0). This is normally a minor shower active between Jan. 16 and 25, with an earlier peak at solar longitude 299.5 deg (cf. Jenniskens 2023, Atlas of Earth's Meteor Showers, p. 525). The parent body is unknown. The short semi-major axis and long-duration activity suggest that the 2024 activity might be dust from a 1P/Halley-type comet trapped in the 1:1 mean-motion resonance with Jupiter. Indeed, the shower was also detected by northern-hemisphere CAMS and SonotaCo stations, with a low radiant elevation, in 2013 during solar longitudes 300.6-302.5 deg.
