Abstract :
[en] P. Jenniskens, SETI Institute and NASA Ames Research Center, reports that, after a strong detection on Aug. 17 (cf. CBET 5159, where it was inadvertently given a provisionally different name), this new shower was no longer detected on Aug. 18 (cf. website URL http://cams.seti.org/FDL/ for the date of 2022 Aug 18). In all, 137 meteors were triangulated by the global CAMS networks, concentrated mainly during two brief time intervals. The first peak was centered on solar longitude 143.16 +/- 0.02 deg (33 orbits), while the second, stronger peak was centered on solar longitude 143.707 +/- 0.008 deg (equinox J2000.0), corresponding to 2022 Aug. 16 at 22h00m UTC (98 orbits). Six meteors were detected outside these intervals. That second outburst was predicted. The parent comet of this meteor shower is now identified as 45P/Honda-Mrkos-Pajdusakova, with the difference in the orientation of the nodal line between current comet orbit and meteor shower mostly a consequence of a close encounter of the comet with Jupiter in 1983. The shower previously associated with this comet from D-criterion searches among photographed orbits is IAU shower number 199, called the August delta Capricornids. M. Maslov predicted an encounter with the 1980 dust of 45P (cf. http://feraj.ru/Radiants/Predictions/45p-ids2022eng.html) on 2022 Aug. 16 around 23h40m UTC and put the radiant at R.A. = 326.8 deg, Decl. = -15.1 deg. The observed coordinates for the second peak were R.A. = 325.28 +/- 0.06, Decl. = -11.40 +/- 0.06 with geocentric velocity 24.12 +/- 0.14 km/s. The earth passed only 0.0038 AU from the center of the dust trail and encountered dust ejected at a modest velocity of 9.8 m/s. This is the first time that an encounter with the dust trails of 45P has been confirmed. The following CAMS networks contributed to this report: 82 meteors were triangulated by CAMS Namibia (coordinated by T. Hanke), 11 by CAMS Chile (S. Heathcote, E. Jehin), 9 by LO-CAMS (N. Moskovitz), 9 by CAMS BeNeLux (C. Johannink), 7 by CAMS California (station operators T. Beck, J. Albers, E. Egland, and B. Grigsby), 5 by CAMS Florida (A. Howell), 5 by CAMS South Africa (T. Cooper), 4 by CAMS Arkansas (L. Juneau), 3 by CAMS Texas (W. Cooney) and 1 by the UAE Astronomical Camera Network (M. Odeh).
