Eta Aquarids Meteor Shower


Eta Aquarids ( ETA )Meteor Shower

Active: April 19–May 28; Maximum: May 5, 20h UT; ZHR = 40 (periodically variable, ≈ 40–85);
V∞ = 66 km/s; r = 2.4.
This stream is associated with Comet 1P/Halley, like the Orionids of October. Shower meteors
are only visible for a few hours before dawn essentially from tropical and southern hemisphere
sites. Some useful results have come even from places around 40◦ N latitude at times however,
and occasional meteors have been reported from further north. The shower is one of the best for
southern observers and would benefit from increased observer activity generally. The fast and
often bright meteors make the wait for radiant-rise worthwhile, and many events leave glowing
persistent trains. While the radiant is still low, -Aquariids tend to have very long paths, which
can mean observers underestimate the angular speeds of the meteors, so extra care is needed
when making such reports.
A relatively broad maximum, sometimes with a variable number of submaxima, occurs around
May 5. IMO analyses based on data collected between 1984–2001, have shown that ZHRs are
generally above 30 in the period May 3–10. The peak rates appear to be variable on a roughly
12-year timescale. Assuming this Jupiter-influenced cycle is real, the next trough is due around
2014–2016, so ZHRs should be close to their relative poorest this year. Activity around the most
recent ZHR peak period in circa 2008 and 2009 seemed to have been ≈ 85 and 65 respectively.
In 2013, ZHRs up to ≈ 70 have been recorded. New Moon on May 6 creates ideal
viewing conditions for whatever the shower provides this year. All forms of observing can be
used to study it, with radio work allowing activity to be followed even from many northern
latitude sites throughout the daylight morning hours. The radiant culminates at about 08h local

Meteor activity increases towards the April-May boundary, particularly caused by optically
unobservable showers. Full Moon on April 22 completely ruins the Lyrid (006 LYR) maximum
at 32 .◦32 which falls on April 22 around 6h UT. The Moon also leaves only very little time
during the evening for the -Puppid (137 PPU) maximum on April 23. In 2016, both the
-Aquariid (031 ETA) maximum period, due around May 5, and the -Lyrids (145 ELY)
with a potential peak on May 9 or slightly later can be perfectly observed in moonless nights.

Credit: IMO