39P/Oterma
39P/Oterma is a currently inactive periodic comet with an orbital period of nearly 20 years that stays outside the orbit of Jupiter. The nucleus has a diameter around 4–5 km. It was last observed in August 2021 and came to perihelion in July 2023 while 1.2 AU from Jupiter. It made a moderately close approach to Jupiter in January 2025 and will next come to perihelion in July 2042 at distance of 5.9 AU from the Sun. Opposition has occurred on 11 November 2023.
Key facts
- Comet.name
- 39P/Oterma
- Comet.discoverer
- Liisi Oterma
- Comet.discovery_date
- 8 April 1943
- Comet.designations
- 1942 VII; 1950 III; 1958 IV; 39P/2001 P3
- Comet.epoch
- 2023-06-25
- Comet.semimajor
- 7.228 AU
- Comet.perihelion
- 5.707 AU
- Comet.aphelion
- 8.75 AU
- Comet.eccentricity
- 0.2105
- Comet.period
- 19.43 yr
- Comet.inclination
- 1.5470°
- Comet.max_speed
- 13.2 km/s
- Comet.min_speed
Article
5 sectionsContents
- Discovery
- Orbit
- Orbital development
- References
- External links
39P/Oterma is a currently inactive periodic comet with an orbital period of nearly 20 years that stays outside the orbit of Jupiter. The nucleus has a diameter around 4–5 km. It was last observed in August 2021 and came to perihelion in July 2023 while 1.2 AU from Jupiter. It made a moderately close approach to Jupiter in January 2025 and will next come to perihelion in July 2042 at distance of 5.9 AU from the Sun. Opposition has occurred on 11 November 2023.
==Discovery== The comet was discovered by Liisi Oterma at Turku University Observatory, Finland on a photo plate on 8 April 1943 as a faint object of 15th magnitude in the constellation of Virgo. Its orbit was calculated by L. E. Cunningham and R. N. Thomas who derived an orbit with a small eccentricity, a perihelion distance of 3.4 AU (i.e. a little outside the main asteroid belt) and an orbital period of 7.9 years.