July 31, 2014

AstroEvent of the Week: 22.06.09: Will the June Bootids Perform?

Bootids.

Looking towards the Zenith-north at +30 Latitude at about 10PM to Midnite. (Created in Stellarium and Paint).

This weeks’ event is a total wild card. Most years, the meteor shower known as the June Bootids warrants nary a second thought, as rates tend to hover around 10 per hour on or around the morning of June 27th. However, this shower is notoriously unpredictable; showers in 1998, 2004 and even as far back as 1916 have produced outbursts in excess of 100 per hour. Predictions this year run the gamut; no large swarm is forecast to intersect the Earth’s orbit, favoring instead 2010. However, this year’s apparition has some things going for it; first, the Moon will be only 5 days past New, and thus out of the picture in the AM hours; the radiant, at northern declination of +48 degrees on the Bootes/Draco border, rides high for northern hemisphere observers. And most interestingly, the progenitor comet, 7P/Pons-Winnecke, just passed perihelion last year. This scenario has produced outbursts in the past. The unpredictable June Bootids are marked by the trains of long, slow, bright fireballs, which differentiates them from several other semi-active summer showers such as the Delta Aquarids. In fact, the radiant rides high enough from the continental US. (it transits around 10 pm local (check)) that the action could begin before local midnight! In any event, this shower is worth checking out; we clearly do not understand all there is to know about the June Bootids!

This week’s astro-term of the week is toroidal sporadics. See a meteor whose train traces back to a high inclination but doesn’t quite match a Bootid or any of its characteristics? You might have spotted one of these poorly understood sporadic meteors. They generally come in at sources highly inclined to the ecliptic and are rare but not impossible to see. The northern toroidal radiant tends to be on a wide dispersal, and is something of interest to watch for on any late night meteor shower vigil.

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