Sky and Telescope - November 2015 - 44

OBSERVING

Celestial Calendar

Taurid Fireball Alert

ROBERT MIKAELYAN

If you see a really bright autumn meteor, note its direction of ﬂight.

At dusk on October 13, 2009, a dazzling ﬁreball grabbed attention across the Netherlands and northern Germany. Some called it as bright as the
full Moon. Sonic booms followed. Was it a Taurid? The date and evening appearance were about right.

November 2015 sky & telescope

this year, we should pass through a
relatively rich band of them. The likeliest
dates, he says, run from shortly before
Halloween to about November 10th.
Prospects are also good for lesser,
more normal meteors. "Four of the last
ﬁve Northern-autumn Taurid returns
have each produced unusual, if variable,
activity," notes the International Meteor
Organization. "So there seems a good
prospect that something may again happen this time."
The strongest recent Taurid return
happened in 2005, when bright meteors
made news around the world. The name
"the Halloween ﬁreballs" for Encke's
spawn seems to date from that return.
One was even apparently seen hitting
the nightside of the waxing Moon that
November 7th. A 7th-magnitude ﬂ ash
was recorded on video; meteor scientists
calculated that it would have been made
by a 12-cm (5-inch) impactor if it arrived
at the Taurids' speed of 27 kilometers
per second (60,000 mph). It probably

made a crater 3 meters (10 feet) wide and
0.4 meter deep.
All expectations for 2015 come with
the usual caveat: meteor showers have a
way of fooling everyone.
Between October 10th and November
25th, the shower's radiant moves all the
way from north of the head of Cetus to
north of Aldebaran. Keep looking up, and
if you see a slow meteor during October
or November, check whether its path
leads back toward that direction.

A Taurid ﬁreball lit up central Texas on the
evening of November 8, 2014. This image,
aired on Austin TV later that night, was
enlarged from a driver's dashcam video.

ARMANDO BUSTAMANTE / KHON-TV

The Taurid meteors of October and
November are like no other shower.
They continue for many weeks, with
two parallel components: the Southern
Taurids running roughly through October
and early November, and the Northern
Taurids from late October through midNovember. Both streams originate from
the periodic comet 2P/Encke. Like the
comet, the Taurids follow unusually shortperiod orbits (about 3.3 years) near the
plane of the ecliptic. Taurids catch up to
the orbiting Earth somewhat from behind,
so they travel unusually slowly across the
sky. This conﬁguration also makes the
shower unusual for being as strong in the
evening hours as in the morning.
And this year the Taurids promise
something more: an especially good
chance for occasional really brilliant
ﬁreballs, the kind that make the public
call the police.
Comet Encke's debris trail is especially rich in large particles. Meteorstream modeler David Asher ﬁnds that

Sky and Telescope - November 2015

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