quai at eps.harvard.edu quai at eps.harvard.edu
Wed Feb 7 16:17:02 EST 2018

                                                  Electronic Telegram No. 4486
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau at eps.harvard.edu (alternate cbat at iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network

     A. V. Moorhead, Meteoroid Environment Office, NASA; P. G. Brown,
University of Western Ontario; M. D. Campbell-Brown, University of Western
Ontario; and D. E. Moser, Jacobs ESSCA Group, Marshall Space Flight Center,
NASA, report enhanced activity associated with the gamma Lyrid (GLY) meteor
shower based on data from the Canadian Meteor Orbit Radar.  Shower activity
was noticeable between 10h and 13h UT on Feb. 5, with a peak (based on
numbers of meteoroid orbits determined from the meteor-echo detections)
between 11h30m and 12h30m UT, corresponding to an equivalent peak ZHR of
40-50 meteors/hr (assuming a differential mass index of 2.0).  Using a
wavelet-based measurement procedure (cf. Brown 2010, Icarus 207, 66), the
mean shower radiant is found to be around R.A. = 285 deg, Decl. = + 34 deg
(equinox J2000.0), with a geocentric velocity of 37 km/s, based on 112
measured echoes.  Significant activity was also detected in 2015; the radiant,
velocity, and solar longitude of the two outbursts is in exact agreement (cf.
Brown 2016, *Proc. of the Int. Meteor Conference*, pp. 42-45).  However,
activity in 2018 was noticeably higher (26 sigma above the background) than
in 2015 (18 sigma). These radar detections are approximately equivalent to
visual magnitudes between +7 and +8.  No corresponding enhancement in optical
meteor detections has been seen in data of the NASA All Sky Fireball Network,
the NASA wide-field camera network, or the Southern Ontario Meteor Network.
The parent body is unknown at this time.

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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2018 CBAT
2018 February 8                  (CBET 4486)              Daniel W. E. Green

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