Leonids
Fastest annual meteor shower, known for storms every 33 years.
The Leonids (LEE-ə-nidz) are a prolific annual meteor shower associated with the comet Tempel–Tuttle, known for spectacular meteor storms that occur about every 33 years. Their name derives from the constellation Leo, from which the meteors appear to radiate, with the suffix -ids indicating they are the offspring of that constellation. Earth moves through meteoroid streams left by the comet, and the Leonids are the fastest annual meteor shower, impacting at 70 km/s.
Quick Facts
- Pronounce
- ˈ · l · iː · ən · ɪ · d · z
- Date
- 902 AD (first record)
- Parent
- 55P/Tempel–Tuttle
- Constellation
- Leo
- Ra
- 10 · 17
- Dec
- +21.6
- Month
- 3 November – 2 December
- Peak
- 17 November
- Velocity
- 70–71
- Zhr
- 15
Facts from the source article.
Lore & Background
The Leonids are famous because their meteor showers or storms can be among the most spectacular. The meteor storm of 12–13 November 1833 broke into modern awareness, with one estimate of over one hundred thousand meteors an hour, and another estimating in excess of 240,000 meteors during nine hours over North America east of the Rocky Mountains. The event was marked by several Native American nations, including the Cheyenne establishing a peace treaty and the Lakota calendar being reset. Abolitionists, slave-owners, and others took note, and the New York Evening Post carried reports from Canada to Jamaica. Denison Olmsted explained the event most accurately, noting the shower radiated from Leo and speculating the meteors originated from a cloud of particles in space. Accounts of the 1866 repeat counted hundreds per minute in Europe, and in 1866–67 Comet Tempel-Tuttle was identified as the source. When storms failed to return in 1899, it was thought the dust had moved on.
Reader's Guide
The Leonids have had a major effect on the scientific study of meteors, which had previously been thought to be atmospheric phenomena, largely due to the storm of 1833 and developments in scientific thought of the time. In 1966, a spectacular meteor storm was seen over the Americas with peak rates exceeding 144,000 meteors per hour, and historical notes were gathered back to 900 AD. Radar studies showed the 1966 storm included a relatively high percentage of smaller particles. In 1981, Donald K. Yeomans reviewed the history of the Leonids and the dynamic orbit of Comet Tempel-Tuttle, showing that meteoroids are mostly behind and outside the comet's path. Leading up to the 1998 return, an airborne observing campaign was organized by Peter Jenniskens at NASA Ames Research Center. Research by Kondrat'eva, Reznikov and colleagues at Kazan University showed how meteor storms could be accurately predicted, and the work of David J. Asher, Robert H. McNaught, and Esko Lyytinen in 1999 is considered the breakthrough in modern analysis, allowing predictions of bursts down to ten minutes. Viewing campaigns produced spectacular footage from the 1999, 2001, and 2002 storms, which produced up to 3,000 Leonid meteors per hour.
Did You Know?
- The 1833 Leonid storm was estimated to have produced over 240,000 meteors during nine hours over North America east of the Rocky Mountains.
- The 1966 Leonid storm had peak rates exceeding 144,000 meteors per hour.
- The Leonids are associated with the comet Tempel–Tuttle and produce storms about every 33 years.
Frequently Asked Questions
What are the Leonids and where do they come from?
The Leonids are an annual meteor shower whose particles originate from debris shed by the comet Tempel–Tuttle. Their name comes from the constellation Leo, which is the apparent point in the sky from which the streaks seem to radiate outward.
What makes the Leonids different from other meteor showers?
They are the fastest of all annual meteor showers, with meteors striking the atmosphere at roughly 70 km/s (about 252,000 km/h). That extreme velocity gives them a distinctive look and sets them apart from slower showers like the Perseids or Geminids.
When do the Leonids peak, and how often do storms happen?
Peak activity arrives around 18 November each year, with the shower active for a couple of weeks on either side. Storm-level displays, producing thousands of meteors per hour, tend to repeat on a cycle of roughly 33 years as Earth re-encounters a dense clump of Tempel–Tuttle debris.
How much material do the Leonids actually deposit on Earth in a normal year?
In a typical non-storm year the Leonids deliver roughly 12 to 13 tonnes of fine particles to the planet's surface. During a storm year that figure can spike dramatically as Earth plows through a much denser section of the debris trail.
Why are the Leonids considered important in meteor astronomy?
Their regular ~33-year storm cycle helped make them one of the first meteor showers for which a parent comet was identified, linking the Leonids to Tempel–Tuttle. That discovery was a key step in establishing the broader understanding that most meteor showers are tied to specific comets and their orbital debris.
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