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Posts Tagged ‘Orionids’

Jupiter Helps Halley’s Comet Give Us Meteor Displays

March 27, 2012 Leave a comment

Image Credit MPS Germany/H.U. Keller/ESA

Image Credit MPS Germany/H.U. Keller/ESA

The dramatic appearance of Halley’s comet in the night sky has been observed and recorded by astronomers since 240 BC. Now a study shows that the orbital influences of Jupiter on the comet and the debris it leaves in its wake are responsible for periodic outbursts of activity in the Orionid meteor showers. The results will be presented by Aswin Sekhar at the National Astronomy Meeting in Manchester on Tuesday 27th March.

Halley’s comet orbits the Sun every 75-76 years on average. As its nucleus approaches the Sun, it heats up and releases gas and dust that form the spectacular tail. This outgassing leaves a trail of debris around the orbit.

When the Earth crosses Halley’s path – twice per orbit – dust particles (meteoroids) burn up in the Earth’s atmosphere and we see meteor showers: the Orionids in October and the Eta Aquariids in May. Previous research has suggested that Orionid meteoroids have at times fallen into ‘resonances’ with Jupiter’s orbit – a numerical relationship that influences orbital behaviour. Sekhar’s new study suggests that Halley itself has been in resonances with Jupiter in the past, which in turn would increase the chances of populating resonant meteoroids in the stream. The particles ejected during those times experience a tendency to clump together due to periodic effects from Jupiter.

Full Story: http://www.jodrellbank.manchester.ac.uk/meetings/nam2012/pressreleases/nam07.html

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Weekend Orionid Meteor Shower

October 21, 2011 Leave a comment

Earth is about to pass through a stream of debris from Halley’s comet, source of the annual Orionid meteor shower.  Forecasters expect more than 15 meteors per hour to fly across the sky on Saturday morning, Oct. 22nd, when the shower peaks.

“Although this isn’t the biggest meteor shower of the year, it’s definitely worth waking up for,” says Bill Cooke of the NASA Meteoroid Environment Office. “The setting is dynamite.”

Orionids are framed by some of the brightest and most beautiful constellations in the night sky. The meteors emerge from mighty Orion, the shower’s glittering namesake.  From there they streak through Taurus the Bull, the twins of Gemini, Leo the Lion, and Canis Major–home to Sirius, the most brilliant star of all.

This year, the Moon and Mars are part of the show.  They’ll form two vertices of a celestial triangle in the eastern sky on Saturday morning while the shower is most active; Regulus is the third vertex.  Blue Regulus and red Mars are both approximately of 1st magnitude, so they are easy to see alongside the 35% crescent Moon.  Many Orionids will be diving through the triangle in the hours before dawn.

Full Story: http://science.nasa.gov/science-news/science-at-nasa/2011/20oct_orionids/