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  • Print publication year: 2006
  • Online publication date: July 2015

17 - The Perseids

from Part III - Young streams from water vapor drag

Summary

The Perseids are the amateur astronomer's main entertainment on sultry summer nights. The Perseids have been around as long as there are records (Chapter 1). They are caused by the largest comet to frequent Earth for thousands of years past, 109P/ Swift–Tuttle, which will continue to frequent Earth for thousands of years to come. When the comet returned in 1992, a series of meteor outbursts were observed that led to my first successful meteor storm chase. One year later, meteor outbursts were the astronomical theme for a Mediterranean cruise and all of America went out to look at the shooting stars.

These meteor outbursts sparked a debate on whether they were caused by young dust trails or the Filament of older trails. In this chapter, I will argue that they were mostly from older trails, making it appropriate that the name ‘Filament’ was first given to these outbursts.

17.1 The 1979–1981 Perseids

Perseid meteoroids approach Earth from a northern direction (Fig. 17.1) with a radiant in the constellation of Perseus at R.A. = 48°, Decl. =+58°, just below the “W” of Casseiopeia.

Parent comet 109P/Swift–Tuttle was last seen in 1862. In 1973, Brian Marsden,at the time director of the IAU's Bureau for Astronomical Telegrams, recalculated the orbit of the comet and predicted a return on September 16.9, 1981 (±1.0 yr), suspecting that a comet seen by astronomer Pehr Wargentin at Uppsala in 1750 was an earlier sighting.