eta-Aquariids 2017: prediction of activity
to the list of predictions
Fig. 1. Space-temporal projection of Perseid trails parts onto their minimal distance passages in 2017 (correspondence between colours of the particles and their ejection velocities can be seen here).
In 2017 the Earth will pass trough space filled with fragments and dust of the comet 1P Halley trail ejected in -616 (616 BC). Considering size and activity of the comet, as well as relative stability of its orbit, even such old trails are able to cause significant activity outbursts, which was proved by eta-Aquariids outburst in 2013 caused by -910 and -1197 trails, according to M. Sato  (our computaions confirm this). In 2013 ZHR reached 120-130 (in usual years it is about 60).
The similar situation will be in 2017, however conditions of encounter with -616 trails are worse than in case of the outburst in 2013. Still, as our computations show, during 14 - 18 UT on 4 May eta-Aquariids activity enhancements are possible with their own ZHR about 20-30 (above background activity). The waxing gibbous Moon will set in the second half of the night, leaving some time with dark sky before dawn, just when the eta-Aquariids are the best visble.
1. "Comet's dust 2.0" program by S. Shanov and S. Dubrovsky. [Used for orbital computations.]
2. Lyytinen E, van Flandern T. "Predicting the strength of Leonid outbursts", 2000, Icarus, P. 158-160.
3. Kasuo Kinoshita, http://jcometobs.web.fc2.com/ [Orbital elements of the comet 109P Swift-Tuttle]
4. Jenniskens P. Meteor showers and their parent comets, 2006, 780 p.
5. Sato, M., Watanabe J. Forecast of enhanced activity of eta-Aquariids in 2013. The Meteoroids 2013, Proceedings of the Astronomical Conference held at A.M. University, Poznań, Poland, Aug. 26-30, 2013, Eds.: T.J. Jopek, F.J.M. Rietmeijer, J. Watanabe, I.P. Williams, A.M. University Press, 2014, p. 213-216