[Baa-ebulletin 00548] HERE COME THE QUADRANTID METEORS

[BAA electronic bulletins service]

BAA e-bulletin, 2011 Jan. 01
HERE COME THE QUADRANTID METEORS

The New Year opens with very favourable conditions for the Quadrantids, one 
of the three most active regular annual showers. Active from January 1-6, 
the Quadrantids have been poorly observed in most recent years thanks to a 
combination of factors - a very narrow period of high activity, poor January 
weather, and moonlight interference in at least one year out of three! 
However, when the shower was last well-covered by BAA observers, a peak ZHR 
of 100-120 m/h was found. Unfortunately, activity is close to peak levels 
for only about six hours: at other times, only a 'trickle' of a few meteor 
per hour might be detected. The Quadrantid radiant (RA 15h 28m Dec +50o) 
actually lies in northern Boötes (in a region occupied by the now defunct 
constellation of Quadrans Muralis), and from the latitudes of the British 
Isles it is circumpolar.

Timing of the Quadrantid peak in January 2011 is quite favourable from the 
UK perspective, especially as the peak coincides with new Moon, so there 
will a complete absence of interference from moonlight. The shower maximum 
is expected around Jan 04d 00h UT, midnight at our longitudes. Although the 
radiant is rather low in the northern sky during the evening hours, it will 
be rising higher by midnight and it climbs to a very favourable elevation as 
dawn approaches.  Observations in the hours after midnight on January 3/4 
will be the most productive.


Local Time          Radiant Altitude             Local Time       Radiant 
Altitude
                             (Lat. 53oN) 
(Lat. 53oN)

17                                22.5o                             00 
21.8o

18                                18.1o                             01 
27.2o

19                                14.9o                             02 
33.3o

20                                13.3o                             03 
41.8o

21                                13.1o                             04 
49.0o

22                                14.6o                             05 
56.9o

23                                17.5o                             06 
66.3o


Much of the high activity close to the peak is comprised of moderately 
bright to faint meteors. As a result of particle-sorting, brighter 
Quadrantids (produced by larger meteoroids) become more numerous following 
the maximum, and this might be evident by dawn on January 4. Quadrantids 
are, like the Geminids, relatively slow meteors, with an atmospheric entry 
velocity of 42 km/sec. The brighter shower members are sometimes strongly 
coloured (often blue or green).

The stream's dynamic orbital history - much perturbed by Jupiter's gravity - 
has made identification of its parent body complicated. Recent studies have 
suggested that the Quadrantids may be debris from asteroid 2003EH1 (another 
similarity with the Geminids!), a possible break-up product of Comet 1490Y1 
following the latter's close approach to Jupiter in 1650.

The Quadrantids can certainly be listed as a shower very much in need of 
observation - so why not make it your New Year's Resolution to start 2011 
with a few hours of meteor watching between midnight and dawn on January 4. 
And, observers who have been out Quadrantid watching during the early 
morning hours of January 4 can reward themselves with a most interesting 
partial eclipse of the Sun at sunrise that morning.

Additional information about the Quadrantid meteor shower is given in the 
'Notes and News' section of the December BAA Journal.


For further details, or copies of report forms, observing notes, and
details of how to carry out group meteor watches, please visit the BAA
Meteor Section website at http://britastro.org/meteor or contact the
undersigned:

John Mason
Acting Director, BAA Meteor Section
email: docjohn at dircon.co.uk

51 Orchard Way, Barnham, West Sussex PO22 0HX