☄ Tempel-Tuttle 55P/Tempel-Tuttle

How to follow comet Tempel-Tuttle live

The panel above recomputes the position of Tempel-Tuttle every second in your browser: its distance from the Sun and from Earth, its position in the sky (right ascension and declination), and a live countdown to the next perihelion. It runs on the same kind of engine observatories use, a Kepler solver applied to the JPL osculating orbital elements, so the numbers are not a static snapshot, they keep ticking.

Just below, the top-down map of the Solar System shows exactly where Tempel-Tuttle is right now among the planets. You can fast-forward time with the day slider, zoom and pan, compare its distance to another body with a click, and press "Next event" to jump straight to perihelion. It is the most direct way to grasp the orbit of Tempel-Tuttle with no math at all.

Comet fact sheet

About Tempel-Tuttle

Comet 55P/Tempel-Tuttle is a short-period comet with an orbital period of roughly 33 years, and the parent body of the Leonids - the November meteor shower that in normal years produces 10 to 15 meteors per hour but in return years can erupt into storms of 1,000 to 150,000 meteors per hour. Independently discovered in 1865 and 1866, it is one of the most studied comets in terms of the relationship between perihelion passages and the intensity of the showers it generates.

The next perihelion is predicted for May 2031. Meteor filament researchers Jeremie Vaubaillon, Esko Lyytinen and David Asher have already published preliminary forecasts indicating possible Leonid storms between 2032 and 2035, depending on which specific filaments Earth will cross.

History and discovery

Ernst Wilhelm Leberecht Tempel (the same astronomer who discovered 9P/Tempel 1, target of the Deep Impact mission) spotted the comet on December 19, 1865, from Marseille, France. Horace Parnell Tuttle, at the U.S. Naval Observatory, independently rediscovered the same object on January 6, 1866. The connection was confirmed by Giovanni Schiaparelli - the same astronomer who mapped the "canals" of Mars - who that year calculated the orbit of the Leonids and showed the shower was produced by debris from the newly discovered comet.

The link between Tempel-Tuttle and the Leonids was the first unambiguous demonstration in astronomical history that meteor showers are caused by comets - a discovery that founded the modern field of meteor physics. Historical records identified later correlate Leonid storms with the comet's perihelion passages across more than a millennium:

Orbit and returns

Tempel-Tuttle orbits the Sun in approximately 33 years (exact period 32.9 years), with perihelion about 0.98 AU from the Sun (nearly the Earth-Sun distance) and aphelion roughly 19.7 AU, near Uranus's orbit. The orbit is retrograde, inclined approximately 162.5 degrees to the ecliptic plane - the comet moves in the opposite direction to Earth when crossing the orbital plane. This head-on collision geometry explains the enormous Leonid entry speed of 71 km/s, the highest of any major annual shower.

The last perihelion occurred on February 28, 1998. The next is predicted for May 2031. At the 1998 pass, the comet came within about 0.36 AU of Earth and was visible to telescopic observers. The Leonids of 1999 and 2001 produced notable storms: November 18, 1999 peaked at roughly 3,700 meteors per hour over Europe and the Middle East; November 18, 2001 peaked near 3,800 per hour over North America. No comparable storms have been recorded since, as Earth has not crossed dense filaments in subsequent years. For the 2031 return, filament models are still being refined.

Nucleus, coma and tail

Tempel-Tuttle's nucleus is small: estimated at only about 1.8 km in diameter, despite generating one of the most dramatic meteor showers in the solar system. This apparent contradiction is explained by the fact that the meteor shower is produced by debris accumulated across many past orbits - not just from material ejected at the most recent return. The comet need not be large or highly productive at each passage to maintain an extensive debris trail.

At the 1998 perihelion, the comet was observed by professional telescopes and developed a coma tens of thousands of kilometers across with a gas and dust tail. Activity was moderate: the comet reached roughly magnitude 8, invisible to the naked eye but accessible to amateur telescopes of 100 mm or more. Spectroscopic composition is typical of CO, CO2 and H2O-rich comets, with detection of CN and C2. As with other short-period comets, the nucleus surface likely has an inactive crust covering most of it, with activity concentrated in smaller sun-facing regions.

How to observe

The Leonids are active from approximately November 6 to 30, peaking around November 17 to 18. The radiant lies near the star Zeta Leonis, in the constellation Leo. In normal years (distant from perihelion), the Leonids produce 10 to 15 meteors per hour - less impressive than the Perseids, but remarkable for speed: 71 km/s, the highest entry velocity among major meteor showers. This produces extremely fast meteors with persistent, often colorful trains that can last several seconds.

In years near perihelion (especially 1 to 3 years after), Earth may cross fresh filaments deposited by the comet on earlier orbits, producing storms with hundreds or thousands of meteors per hour. The difference between a normal year and a storm year is dramatic: 10 meteors per hour versus 3,000. Predicting crossings of specific filaments is now a well-developed specialty, with teams publishing detailed storm calendars for each return.

For optimal Leonid viewing: naked-eye observation in open fields, preferably between 1 a.m. and 5 a.m. (when the Leo radiant is well elevated in the eastern sky), on the nights of November 17 to 19. Cameras on tripods with high ISO and 20 to 30-second exposures capture the long trails of brighter meteors. For the 2031 to 2035 period, watch for filament predictions published by AMS, IMO and European research groups.

Missions and scientific exploration

No spacecraft has visited 55P/Tempel-Tuttle directly. However, the comet is scientifically relevant through two indirect avenues: Leonid meteors studied by radar and spectroscopy, and debris filament modeling that enabled advance storm predictions in 1999 and 2001.

The 1999 storm was predicted with precision by Esko Lyytinen (Finland) and David Asher (Armagh Observatory, UK), who calculated that Earth would cross the debris filament deposited by the comet in 1899. The prediction was so precise it specified the peak timing to within less than one hour - marking the beginning of the era of quantitative meteor storm prediction, analogous to eclipse prediction.

Spectroscopic analysis of Leonid meteors has revealed composition rich in iron, magnesium and sodium, with abundant volatile organic compounds. The high entry speed (71 km/s) enables study of fragment ablation in detail impossible with slower showers. Multiple studies in the 2000s and 2010s used the Leonids as a laboratory for understanding cometary chemical composition without needing spacecraft missions.

Trivia and records

• The Leonid storm of November 13, 1833 was described by witnesses as "a rain of stars so dense the sky seemed on fire," with estimates of 100,000 meteors per hour. The event spurred the first serious scientific studies of meteors in the United States and Europe.
• Giovanni Schiaparelli was the first to calculate, in 1866, that both the Leonids and Perseids were produced by cometary debris - founding the modern science of meteor physics as a discipline.
• Leonid entry speed (71 km/s) is so high that millimeter-sized fragments produce luminous trails several seconds long - the so-called "persistent trains" - visible even under moderate light pollution.
• The storm of November 1966 produced estimated rates of 40,000 to 150,000 meteors per hour over the western United States, one of the most intense ever photographically documented. Observers reported being unable to count individual meteors.
• The comet has one of the smallest nuclei among short-period comets: only 1.8 km across. Despite that, the accumulated debris trail is large enough to produce the greatest meteor storms on record.
• Historical Arabic and Chinese records allow Leonid storms to be correlated with the comet's perihelion passages for more than 1,100 continuous years - one of the longest historical archives of any recurring astronomical event.

Other comets

See the full comet catalogue.