Electronic Telegram No. 5072
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)
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Prepared using the Tamkin Foundation Computer Network


ANDROMEDID METEOR SHOWER 2021
     P. Jenniskens, SETI Institute and Ames Research Center, NASA, reports
that significant Andromedid (IAU shower 18) activity is being detected this
year by northern-hemisphere networks of the CAMS video-based meteoroid-orbit
survey in the BeNeLux countries (coordinated by C. Johannink and M. Breukers),
Turkey (O. Unsalan), the United Arab Emirates (M. Odeh), Florida (A. Howell),
Texas (W. Cooney, D. Samuels), Arkansas (L. Juneau), Arizona (N. Moskovitz),
and California (J. Albers, T. Beck).  The shower was first detected on 2021
Oct. 28, when the radiant was near the ecliptic plane.  The radiant slowly
rose to higher ecliptic latitudes while rates increased until a broad maximum
on Nov. 9, when on average one Andromedid was triangulated for every 68
sporadic meteors.  After that, rates declined until a reversal occurred (cf.
website URL http://cams.seti.org/FDL/ for dates of 2021 Nov. 20-22).  Starting
on Nov. 20, rates have been significantly above the previous trend.  On Nov.
22, there was one Andromedid triangulated for every 42 sporadic meteors, and
rates appeared to be rising; on that day, the geocentric radiant was located
in the constellation Andromeda at R.A. = 25.2 +/- 1.0 deg, Decl. = +39.5 +/-
0.7 degrees (equinox J2000.0), while meteors entered the atmosphere with
geocentric velocities of 17.9 +/- 2.2 km/s (apparent velocity 21.0 km/s).
Median orbital elements were a = 4.5 AU, q = 0.828 +/- 0.013 AU, e = 0.816
+/- 0.128, i = 12.9 +/- 1.2 deg, Peri. = 230.7 +/- 1.0 deg, and Node = 239.8
+/- 0.1 deg (equinox J2000.0).  The parent comet is 3D/Biela.  Note that the
historic Andromedid storms from 1872 and 1885 radiated from R.A. = 27 deg,
Decl. = +45 deg on Nov. 27, but no such high activity is expected this year.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2021 CBAT
2021 November 24                 (CBET 5072)              Daniel W. E. Green