My first Magazine Sky & Telescope - 01.2019 | Page 50

JANUARY 2019 OBSERVING
Celestial Calendar by S. N. Johnson-Roehr
The Odd Quads
We’re still learning the secrets of this young and mysterious meteor shower.
Astrophotographer Frankie Lucena
caught this rare view of a Qua-
drantid meteor on January 2, 2003,
just a few months before Peter
Jenniskens identii ed the asteroid
2003 EH 1 as the probable parent
body for the shower. It’s unusual for
Quadrantids to travel so far south,
but this one was spotted streaming
across the top of Crux, the Southern
Cross. To the right of Crux is Eta
Carinae. The meteor was captured
with a 30-second exposure taken
with a i lm camera at ISO 800 and a
50-mm lens at f/1.8.
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JA N UA RY 2 019 • SK Y & TELESCOPE
T
he January meteor shower known as the Quadrantids is an anomaly
among major meteor events. It’s a young shower — sightings of
its component meteoroids were fi rst noted in January 1835, quite late
compared to the Lyrids, for instance, which have been on record since
at least 687 BC. The Quadrantid shower is also the shortest of the
major showers, with a peak lasting only four hours or so. This short
viewing window suggests Earth passes through a narrow stream that’s
no more than 500 years old. Due to the relatively young age of the
stream, the dust and particles haven’t had much time to disperse into a
broader lane of dust.
As recently as 15 years ago, scientists could only speculate as to the
origin of the Quadrantids. There was no obvious parent for the debris
stream, making it the only major shower without a known source.
Various models offered various possibilities, of which two stood out as
the most reasonable: a stream left by Comet 96P/Machholz 1 between
2,000 and 5,000 years ago, and one left by Comet C/1490 Y1 as many
as 5,000 years ago. Or perhaps both. The shower could have developed
from a wide complex of dust trails left by two or more passing comets,
with the streams merging only in the last 150–200 years.