Sunday, October 7, 2012
Draconid meteor shower...October 7-8
Earth is about to pass through a stream of debris from comet 21P/Giacobini-Zinner, source of the annual Draconid meteor shower. Last year, Europeans witnessed a faint but furious outburst of 600 meteors per hour when the shower peaked. No such display is expected this year, but the Draconids are notoriously unpredictable. Northern-hemisphere sky watchers should be alert for slow-moving meteors emerging from the head of the constellation Draco the Dragon (not far from the North Star) on Sunday night, Oct 7th, through Monday morning Oct. 8th.
Comet Giacobini–Zinner (official designation: 21P/Giacobini–Zinner) is a periodic comet in the Solar System.
It was discovered by Michel Giacobini from (Nice, France), who observed the comet in the constellation of Aquarius on December 20, 1900. It was recovered two passages later by Ernst Zinner (from Bamberg, Germany) while observing variable stars near Beta Scuti on October 23, 1913.
During its apparitions, Giacobini–Zinner can reach about the 8th magnitude, but in 1946 it underwent a series of outbursts that made it as bright as 5th magnitude. It is the parent body of the Giacobinids meteor shower (also known as the Draconids).
Giacobini–Zinner was the target of the International Cometary Explorer spacecraft, which passed through its plasma tail on September 11, 1985. In addition, Japanese space officials considered redirecting the Sakigake interplanetary probe toward a 1998 encounter with Giacobini–Zinner, but that probe lacked the propellant for the necessary maneuvers and the project was abandoned.
The comet nucleus is estimated to be 2.0 kilometers in diameter.