29P/Schwassmann–Wachmann
Comet 29P/Schwassmann–Wachmann, also known as Schwassmann–Wachmann 1, was discovered on November 15, 1927, by Arnold Schwassmann and Arno Arthur Wachmann at the Hamburg Observatory in Bergedorf, Germany. It was discovered photographically, when the comet was in outburst and the magnitude was about 13. Precovery images of the comet from March 4, 1902, were found in 1931 and showed the comet at 12th magnitude. It reached the last perihelion on March 7, 2019. It came to opposition in late December 2022.
| Discovery | |
|---|---|
| Discovered by | Arnold Schwassmann Arno Arthur Wachmann |
| Discovery date | November 15, 1927 |
| Designations | |
Alternative designations | 1908 IV; 1927 II; 1941 VI; 1957 IV; 1974 II; 1989 XV; |
| Orbital characteristics | |
| Epoch | March 6, 2006 |
| Aphelion | 6.25 AU |
| Perihelion | 5.722 AU |
| Semi-major axis | 5.986 AU |
| Eccentricity | 0.0441 |
| Orbital period | 14.65 a |
| Max. orbital speed | 12.7 km/s |
| Inclination | 9.3903° |
| Last perihelion | March 7, 2019 |
| Next perihelion | Feb 18, 2035 |
| Physical characteristics | |
| Dimensions | 60.4 ± 7.4 km |
Synodic rotation period | 12.1 ± 1.2 d |
The comet is a member of a class of objects called "Centaurs", of which at least 500 are known. These are small icy bodies with orbits between those of Jupiter and Neptune. The Centaurs have been recently perturbed inward from the Kuiper belt, a disk of trans-Neptunian objects occupying a region extending from the orbit of Neptune to approximately 50 AU from the Sun. Frequent perturbations by Jupiter will likely accumulate and cause the comet to migrate either inward or outward by the year 4000. A number of Centaurs appear to be dynamically and perhaps even physically related to 29P; such objects may traverse the coma of 29P when in outburst.
The comet nucleus is estimated to be 60.4±7.4 kilometers in diameter.