Orionids

The Orionids meteor shower, often shortened to the Orionids, is one of two meteor showers associated with Halley's Comet (the other one being the Eta Aquariids). The Orionids are named because the point they appear to come from (the radiant) lies in the constellation of Orion. The shower occurs annually, lasting approximately one week in late October. In some years, meteors may occur at rates of 50–70 per hour.

Orionid outbursts occurred in 585, 930, 1436, 1439, 1465, and 1623. The Orionids occur at the ascending node of Halley's comet. The ascending node reached its closest distance to Earth around 800 BCE. Currently Earth approaches Halley's orbit at a distance of during the Orionids. The next outburst might be in 2070 as a result of particles trapped in a 2:13 mean-motion resonance with Jupiter.

History Meteor showers were connected to comets in the 1800s. E.C. Herrick made an observation in 1839 and 1840 about the activity present in the October night skies. Alexander Herschel produced the first documented record that gave accurate forecasts for the next meteor shower. The Orionids meteor shower is produced by Halley's Comet, which was named after astronomer Edmund Halley and last passed through the inner Solar System in 1986 on its 75–76 year orbit. When the comet passes through the Solar System, the Sun sublimates some of the ice, allowing rock particles to break away from the comet. These particles continue on the comet's trajectory and appear as meteors when they enter Earth's upper atmosphere.

The meteor shower radiant is located in Orion about 10 degrees northeast of Betelgeuse. The Orionids normally peak around October 21–22 and are fast meteors that make atmospheric entry at about . Halley's comet is also responsible for creating the Eta Aquariids, which occur each May as a result of Earth passing close to the descending node of Halley's comet.

An outburst with a zenithal hourly rate of over 100 occurred on 21 October 2006 as a result of Earth passing through the 1266 BCE, 1198 BCE, and 911 BCE meteoroid streams. In 2015, the meteor shower peaked on October 26.

Year Activity Date Range Peak Date ZHRmax1839October 8–151864October 18–201936 October 191981October 18–21 October 23 201984October 21–24 October 21–24 (flat maximum)2006October 2 — November 7 October 21–24 100+2007October 20–24 October 21 (predicted) 70Orionids 2007: visual data quicklook. imo.net2008October 15–29 October 20–22 (predicted) 392009October 18–25 October 22 45Orionids 2009. imo.net2010 October 23 382011 October 22 332012October 2 — November 7 October 20 and October 2343Orionids 2012: visual data quicklook. imo.net2013 October 22 ~302014October 2 — November 7 October 21 282015October 2 — November 7 October 26 372016October 2 — November 7 October 21 84MeteorFlux 2.3 (Select Shower: ORI, uncheck "Use temporary database", select year (such as 2016) and click "Create graph")2017 October 21 552018 October 21 582019 October 22 402020 October 22 362021 October 21 412022 October 22 382023 October 21 48

Some Orionid showers have had double peaks, as well as plateaus of activity lasting several days.

Gallery

Orionids

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