45P-ids 2019: prediction of activity
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Fig. 1. Space-temporal projection of Ursid trails parts onto their minimal distance passages in 2016 (correspondence between colours of the particles and their ejection velocities can be seen here).

In the beginning of November 2019 the Earth will come close to 1927 trail of comet 45P Honda-Mrkos-Pajdusakova. Parameters of the encounter are following: minimum distance 0.00109 AU, ejection velocity 54.78 m/s, trail density - 23.7% of that for 1 rev. Leonid trail, computed date and time of maximum is November 6, 3:27 UT. So far, the ejection velocity is very high, it means that particles in this part of trail are very small, so they could produce only faint meteors. Trail density is also quite low. Considering these parameters, we expected that visual acitity could be only at the level of separate meteors at best, with ZHR not higher than 10. In radiorange acitivity could be higher.
Fig. 2. The Earth as seen from coming 45P-ids meteors (RA=345.2°, Dec=+23.2°) during the expected maximum time of outburst from 1927 trail at 3:27 UT 6 November.

If it happens at the given time, this activity could be visible very well in the almost entire space of Northern and Central Americas, as well in north-western past of Southern America and north-eastern part of the Pacific. Unfortunately this case is significantly spoiled by the almost full Moon in the phase of 0.95 which will create strong light pollution.


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. Jenniskens P. Meteor showers and their parent comets, 2006, 780 p. 4. Kasuo Kinoshita, http://jcometobs.web.fc2.com/ [Orbital elements of the comet 8P Tuttle]
5. Hewgill G. Xearth 1.1.0 (Software program), 2003. 6. Molau S. Results of the IMO Video Meteor Network – December 2014. http://www.imonet.org/reports/201412.pdf 7. 2016 Meteor Shower Calendar, http://imo.net/files/data/calendar/cal2016.pdf