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(meteorobs) "Eta Perseid" findings
I have completed a sweep through my various visual, photographic, and radio
meteor databases and have found relatively little evidence to support the
existence of this stream in the past. I basically searched the entire month of
June in every database, with my main search parameters set to find anything
with a radiant in the range of RA=35...45, DEC=48...64.
Visually, activity is completely absent from the lists of the AMS, Denning,
Herschel, King, and many others. Likewise, there is no trace of Eta Perseid
activity in my database of nearly 8000 photographic meteor orbits. I did find 5
possible candidates among nearly 40000 radio meteor orbits, and, curiously,
these fell within a solar longitude range of 113.8 degrees to 114.7 degrees,
compared to the range of 115.0 to 116.1 based on George Zay's observations. On
the negative side, however, these 5 meteors have rather small semi-major axes
and could not produce the speeds indicated.
My conclusion is that if this activity was observed this year (I have to say it
like this everyone) it must be from a hitherto unknown stream--possibly new or
maybe periodic. If the radio meteors are any indication, there is a chance this
could be a very narrow stream which produces activity for only a very short
period of time (two or three days), which is not unusual considering the
orbital inclination of 75 degrees indicated by the radio meteor orbits. It is
also worth noting that such a short duration could explain why the stream is
not represented in the other databases. There are currently no known comets or
asteroids with orbits similar to that indicated for this stream (either the
parabolic orbit I computed for the observed radiant or the short-period orbit
indicated by the radio meteors. Future searches for activity should be
undertaken.
Sincerely,
Gary W. Kronk