96P/Machholz
Comet Machholz 1 as seen by the STEREO-A spacecraft in April 2007 | |
| Discovery | |
|---|---|
| Discovered by | Donald E. Machholz |
| Discovery site | Loma Prieta, California |
| Discovery date | 12 May 1986 |
| Designations | |
| P/1986 J2 | |
| |
| Orbital characteristics | |
| Epoch | 21 November 2025 (JD 2461000.5) |
| Observation arc | 38.17 years |
| Number of observations | 1,559 |
| Aphelion | 5.946 AU |
| Perihelion | 0.116 AU (25 R☉) |
| Semi-major axis | 3.031 AU |
| Eccentricity | 0.96173 |
| Orbital period | 5.277 years |
| Max. orbital speed | 122 km/s (440,000 km/h) |
| Inclination | 57.586° |
| 93.963° | |
| Argument of periapsis | 14.739° |
| Mean anomaly | 191.35° |
| Last perihelion | 31 January 2023 |
| Next perihelion | 12 May 2028 |
| TJupiter | 1.942 |
| Earth MOID | 0.333 AU |
| Jupiter MOID | 0.613 AU |
| Physical characteristics | |
Mean radius | 3.2 km (2.0 mi) |
| Comet total magnitude (M1) | 13.7 |
| Comet nuclear magnitude (M2) | 16.9 |
Comet 96P/Machholz, also known as Machholz 1 is a periodic sunskirting comet discovered on 12 May 1986, by amateur astronomer Donald Machholz on Loma Prieta peak, in central California using 130 mm (5.1 in) binoculars. On 6 June 1986, 96P/Machholz passed 0.404 AU (60.4 million km; 37.6 million mi) from the Earth. 96P/Machholz last came to perihelion on January 31, 2023. The comet has an estimated diameter of around 6.4 km (4.0 mi).
This comet is the parent body of both the Kracht and Marsden sungrazer families.
96P/Machholz is unusual among comets in several respects. Other than small SOHO comets, its highly eccentric 5.29 year orbit has the smallest perihelion distance known among numbered/regular short-period comets, bringing it considerably closer to the Sun than the orbit of Mercury. It is also the only known short-period comet with both high orbital inclination and high eccentricity. In 2007, 96P/Machholz was found to be both carbon-depleted and cyanogen-depleted, a chemical composition nearly unique among comets with known compositions. The chemical composition implies a different and possible extrasolar origin.