The October Draconids, in the past also unofficially known as the Giacobinids, are a
Northern hemisphere
The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...
meteor shower
A meteor shower is a celestial event in which a number of meteors are observed to radiate, or originate, from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at ext ...
whose parent body is the periodic
comet
A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...
21P/Giacobini-Zinner. They are named after the constellation
Draco
DRACO (double-stranded RNA activated caspase oligomerizer) is a group of experimental antiviral drugs formerly under development at the Massachusetts Institute of Technology. In cell culture, DRACO was reported to have broad-spectrum efficacy aga ...
, where they seemingly come from. Almost all meteors which fall towards Earth
ablate
Ablation ( – removal) is the removal or destruction of something from an object by vaporization, chipping, erosive processes, or by other means. Examples of ablative materials are described below, including spacecraft material for ascent and ...
long before reaching its surface. The Draconids are best viewed after sunset in an area with a clear dark sky.
The 1933
["The meteors from Giacobini's comet", Wylie, C. C., ''Popular Astronomy'', Vol. 42, p. 44, ] and 1946
Draconids had
zenithal hourly rate
In astronomy, the zenithal hourly rate (ZHR) of a meteor shower is the number of meteors a single observer would see in an hour of peak activity if the radiant was at the zenith, assuming the seeing conditions are perfect (when and where stars w ...
s of thousands of meteors visible per hour, among the most impressive meteor storms of the 20th century. Rare outbursts in activity can occur when the Earth travels through a denser part of the cometary debris
stream
A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a strea ...
; for example, in 1998, rates suddenly spiked
[Arlt, R]
"Summary of 1998 Draconid Outburst Observations"
''WGN, Journal of the International Meteor Organization, Vol. 26, p. 256-259'', 1998. but only increased modestly in 2005.
[Campbell-Brown, M.; Vaubaillon, J.; Brown, P.; Weryk, R. J.; Arlt, R]
"The 2005 Draconid outburst"
''Astronomy and Astrophysics'', Volume 451, pp. 339–344, 2006. A Draconid meteor outburst occurred
as expected
on October 8, 2011, though a waxing
gibbous Moon
A lunar phase or Moon phase is the apparent shape of the Moon's directly sunlit portion as viewed from the Earth. Because the Moon is Tidal locking, tidally locked with the Earth, the same Hemisphere (geometry), hemisphere is always facing the ...
reduced the number of meteors observed visually. During the 2012 shower radar observations (which detect smaller and fainter meteors) detected up to 1000 meteors per hour. The 2012 outburst may have been caused by the narrow trail of dust and debris left behind by the parent comet in 1959.
References
* Michael D. Reynolds
''Falling Stars'' Stackpole Books, 2001. p. 42.
* Jun-Ichi Watanabe and Mikiya Sato
"Activities of Parent Comets and Related Meteor Showers" Earth, Moon, and Planets, Vol 102, No 1-4 (June 2008). p111-116.
External links
(
Astronomy Picture of the Day
Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include ...
2011 October 19)
The 2012 Draconid Storm Potentially Sampled By NASA ER-2 Aircraft (item 12)
Meteor showers
October
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