November 19, 2018

AstroEvent: The Geminids Round Out 2011.

2011 has been quite a year, both terrestrial and otherwise. This week sees the last of the big scheduled astronomical happenings of the year in the form of the Geminid meteor shower. This shower is one of the yearly standbys along with the Perseids that are always sure to produce. The Geminids have a long peak centered on the morning of December 14th when an idealized Zenithal Hourly Rate (ZHR) of up to 120 meteors per hour may be seen. Problems will arise, however, from an 82% illuminated waning gibbous Moon in the adjacent constellation of Cancer. Rising roughly around 10PM local on the night of the peak, this makes for the worst possible Moon phase as itíll be high and bright in the early AM hours, just as the meteor shower is getting into high gear. But as always, I wouldnít let that stop you from looking! To use a rough sports analogy, youíll see zero meteors if you do not try.

Moon path and position on the 14th. (Created by author is Starry Night & Paint).

This shower is also unique in that its source isnít a comet, but an asteroid named 3200 Phaethon. The first asteroid discovered by a spacecraft, namely the Infrared Astronomical Satellite in 1983, thereís a fair amount of conjecture as to exactly what 3200 Phaethon is; is it a true Palladian-type asteroid or an inactive comet nucleus? [Read more...]