July 24, 2014

Astro-Event: A Possible “Taurid Swarm?”

A Taurid meteor streaks through an All-Sky Cam. (Credit: NASA).

A relatively obscure meteor shower may be on the upswing in the coming month, starting this week. The Northern Taurids are usually a minor shower, of little note on most years. Generating a maximum zenithal hourly rate just a little above the background sporadic level of about 5 per hour, the Northern Taurids go unnoticed on most years. Active from October 20th through December 10th with a broad peak centered on November 12th, the radiant drifts across the border from the constellation Aries into northern Taurus just below The Pleiades (M45) open star cluster.

The path of the radiant of the Northern Taurids. (Photo & Graphic by Author).

Fred Whipple’s analysis of the radiant of the Northern Taurids in the early 1950’s revealed a path wandering from a Right Ascension of 3 Hours 00’ and a declination of +19° degrees in the constellation Aries in mid-October into Taurus very near the Pleiades at a R.A. of 4 Hours and 7.7’ and a declination of 24.5° degrees on December 1st.

In fact, researchers in the mid-20th century discovered that the two Taurid streams are tangled up with two other faint streams, known as the Autumn or Northern & Southern Arietids.

So, what’s so significant about a minor meteor shower? Well first off, the Northern Taurids are known to produce a disproportionate amount of bright fireballs. The Moon reaches Full phase on October 28th at 3:49PM EDT/7:49 PM UTC, but that shouldn’t be a hindrance for any bright fireball sightings. General meteor velocities for the Northern Taurids are about 29 kilometres per second, lending themselves to long, graceful meteor trails. This has also lent the nickname “The Halloween Fireballs” to the Northern Taurids over the years.

Both the Southern and Northern Taurids emanate from debris shed by that most famous of ultra-short period comets, Comet 2P/Encke. The Southern Taurids have a radiant that runs roughly parallel though the southern portion of the constellation Taurus with a ZHR=5 and are also currently active from September 10 – November 20th. In fact, it may be tough to disentangle the source radiant of the two, as they only lie about 10° degrees apart. Comet Encke has the shortest orbital period of any known comet at 3.3 years, and there’s some thought that the streams of all four showers converge on points 4,700 and 1,500 years ago, hinting at a large breakup and discharge of material around those times.

The Northern Taurids have seen a recent upswing in activity on the years 1995, 1998, 2005 and 2008. Current modeling suggests that we encounter a “swarm” of Taurid fireballs once every 61 years, as last occurred, you guessed it, 61 years ago in 1951. In fact, it was the “Taurid fireball swarm of 1951” that solidified the stream as a true meteor shower in the first place. Of course, this shower has only been monitored for less than a century, and it’s to be seen if the 61 year hypothesis holds true.

Just only this year, the International Astronomical Union raised the number of established meteor showers from 64 to 95. To be sure, there are lots more streams out there, and clumps of debris in known showers that we’ve yet to encounter. There’s already talk of a possible new mid-December radiant dubbed the “46/P-ids” that may becoming active, along with a return of the defunct Andromedids in early December and a possible meteor storm from Comet 209P/LINEAR in May of 2014. Incidentally, that last one will hail from the constellation Camelopardalis, perhaps giving birth to… wait for it… the Camelopardalids! That’ll be a fun one for the non-science media to explain!

Do keep a watch on the sky for Taurid fireball activity over the next few weeks. The radiant rises to the northeast just after sunset and will be high overheard by local midnite for mid-northern latitude observers through November. Watch those all-sky cameras for activity as well. Will we witness a “Great Taurid Swarm of 2012?” remember, you won’t see any if you don’t try!

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