☄ Schaumasse 24P/Schaumasse

How to follow comet Schaumasse live

The panel above recomputes the position of Schaumasse every second in your browser: its distance from the Sun and from Earth, its position in the sky (right ascension and declination). 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 Schaumasse 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 Schaumasse with no math at all.

Comet fact sheet

About Schaumasse

24P/Schaumasse was discovered on 1 December 1911 by French astronomer Alexandre Schaumasse at Nice Observatory on the French Riviera. The detection was made visually, without photography, which was unusual for the time and speaks to Schaumasse's skill as a visual sky-sweeper.

With an orbital period of about 8.22 years, the comet belongs to the Jupiter family, the group of short-period comets whose orbits are governed primarily by the gravitational pull of the Solar System's largest planet. Its history includes a gap of nearly 40 years without observation, a record of absence for a periodic comet that turned out to be still intact.

History and discovery

Alexandre Schaumasse was working at Nice Observatory when he spotted the comet in December 1911 through a refracting telescope. At the time Nice Observatory was renowned for the quality of its sky and its tradition of comet and asteroid discoveries; it was there that astronomer Coggia had found Comet Coggia in 1874, one of the brightest of the nineteenth century.

The orbit was calculated by Heinrich Kreutz and other computers of the era, who derived a period of about 8 years. The comet was lost after the 1913 return, considered by many catalogues as possibly extinct, and went unobserved for nearly 40 years. Only in 1952, with the systematic use of wide-field photographic plates, was it recovered, confirming that the nucleus had survived decades of orbital solitude intact.

Orbit and returns

24P/Schaumasse's perihelion lies at approximately 1.20 AU from the Sun, just inside Earth's orbit, while aphelion reaches about 4.9 AU. The Tisserand parameter with respect to Jupiter is around 2.9, within the classic criterion for Jupiter-family comets.

The period is not perfectly constant: close encounters with Jupiter across the twentieth century have shifted it between 8.0 and 8.4 years in different orbits. The most recent perihelion occurred in September 2017, when the comet reached visual magnitude around 11 to 12. The next perihelion is expected in November 2025.

Nucleus and dynamic family

The nucleus of 24P/Schaumasse is estimated at under 2 km in diameter, placing it among the smaller-nucleus known periodic comets. That small size, combined with perihelion at 1.20 AU, limits how much gas and dust the comet can release at each passage, explaining its moderate brightness even at its best returns.

As a Jupiter-family member, 24P shares dynamics with more than 400 catalogued comets whose orbits were shaped by repeated gravitational encounters with Jupiter. Smaller nuclei like Schaumasse's tend to exhaust themselves faster: at each perihelion, ice sublimation removes a proportionally larger fraction of mass than in larger nuclei. Lifetime estimates for sub-2 km Jupiter-family nuclei suggest many will exhaust within fewer than 10,000 years of their current orbits.

How to observe

On typical returns 24P/Schaumasse reaches magnitude 11 to 13, requiring a telescope of at least 150 mm aperture and a dark sky. The coma appears compact with moderate central condensation, which helps detection even when no tail is visible. A 200 mm telescope with a low-power eyepiece (30x to 50x) under a clean sky is enough to identify it as a diffuse glow.

For the November 2025 return, the best observing window falls in the months immediately before perihelion, when heliocentric distance is dropping rapidly and brightness is rising. Check JPL Horizons for precise daily positions.

• Minimum aperture: 150 mm
• Best magnification: 40x to 80x
• Typical peak magnitude: 11 to 12
• Next perihelion: November 2025

Science and notable observations

The comet has been studied spectroscopically on several returns. Near-infrared observations detected silicate and carbonaceous emission in the coma, consistent with the typical composition of Jupiter-family comet nuclei. The water production rate (Q_H2O) was estimated at around 10^27 molecules per second at perihelion, a modest but consistent figure across documented apparitions.

The long absence between 1913 and 1952 made 24P a case study in the difficulty of maintaining records of short-period comets before the era of systematic photography. Its 1952 recovery showed the nucleus had neither fragmented nor depleted, suggesting a low activity rate per unit of nuclear surface area, consistent with the modest brightness observed at every return.

Facts worth knowing

• Nice Observatory, where Schaumasse worked, was built in 1881 with funding from banker Raphael Bischoffsheim and housed one of the largest refractors in Europe at the time.
• The comet was "lost" for nearly 40 years before being recovered in 1952, a gap long enough for some catalogues to list it as extinct.
• The nucleus of 24P/Schaumasse is estimated at under 2 km in diameter, among the smallest of periodic comets with well-documented orbits.
• Schaumasse spotted the comet visually without photography at a time when most discoveries were already being made on photographic plates, demonstrating exceptional skill as a naked-eye sky sweeper.
• With perihelion at 1.20 AU, the comet passes closer to the Sun than Mars but never approaches Earth as closely as comets with sub-1 AU perihelia, limiting its maximum Earth-approach distances.
• Despite its modest brightness, the comet has been captured on wide-field photographic films as an 11th-magnitude fuzzy patch, sharing frames with Messier-catalogue galaxies.

Other comets

See the full comet catalogue.