Electronic Telegram No. 2763
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


FEBRUARY ETA DRACONIDS
     P. Jenniskens, SETI Institute, reports the detection of a meteor outburst
from a previously unknown shower on 2011 February 4 during routine
low-light-level video triangulations with NASA's Cameras for Allsky Meteor
Surveillance (CAMS) project in California between 2h20m and 14h20m UT.
During that time interval, six meteors radiated from a compact geocentric
radiant at R.A. = 239.92 +/- 0.50 deg, Decl. = +62.49 +/- 0.22 deg, with
velocity V_g = 35.58 +/- 0.34 km/s.  The times of arrival for the meteors were
6h25m, 7h59m, 10h49m, 11h18m, 12h14m, and 13h33m UT, suggesting that the
outburst peaked around 11h UT (solar longitude 315.1 deg) and had a duration
of at least 7 hours.  The shower was not detected on the days prior to or
after Feb. 4.  The meteors were in a narrow magnitude range, with peak visual
magnitudes of 2.1, 1.9, 2.6, 2.1, 2.3, and 2.4, respectively, moving from
103.6 +/- 1.4 to 95.7 +/- 1.5 km in altitude.  The mean meteoroid orbital
elements derived from the radiant and speed are q = 0.971 +/- 0.001 AU,
1/a = -0.004 +/- 0.025 1/AU, i = 55.20 +/- 0.34 deg, Peri. = 194.09 +/-
0.35 deg, Node = 315.07 +/- 0.10 deg (equinox 2000.0; one standard deviation).
The orbital period of this shower is P > 52 y (three standard deviations), so
that the meteoroids are likely the dust trail of an earth-threatening
long-period comet that remains to be discovered.  Based on the measured orbit,
Esko Lyytinen (Helsinki) calculated a possible return of the shower in 2016
or 2023, with the next return not unil 2076.  CAMS is supported by the NASA
Planetary Astronomy program, and the project website is at the following
website URL:  http://cams.seti.org.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2011 CBAT
2011 July 10                     (CBET 2763)              Daniel W. E. Green