38P/Stephan–Oterma (also known as Comet Stephan–Oterma) is a periodic comet with an orbital period of 38 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years).[1] It was discovered in January 1867, by Jérôme Eugène Coggia at Marseilles Observatory, France.[1]

Discovered byCoggia, Jerome E.
Discovery dateJanuary 22, 1867
P/1980 L2, P/1942 V1, P/1867 B1, 38P
Orbital characteristics A
(JD 2444720.5)[1]
Aphelion20.920 AU
(near Uranus orbit)
Perihelion1.5744 AU
(near Mars orbit)
Semi-major axis11.247 AU
Orbital period37.72 yr
Last perihelionNovember 10, 2018[2][3]
December 5, 1980[1][3]
Next perihelion2056-Aug-28[2]

38P/Stephan–Oterma last came to perihelion on November 10, 2018.[2][3] It was recovered by Pan-STARRS on June 24, 2017 while 5.3 AU from the Sun.[2] The next perihelion passage is August 28, 2056.[2]


It has perihelion near the orbit of Mars and has aphelion near the orbit of Uranus. Acting like a centaur-hybrid, between the years 1982 and 2067, this object will make close approaches to the giant planets Jupiter, Saturn, and Uranus.[4] If this object did not have a coma and (for some definitions) had a perihelion beyond Jupiter's (5 AU), it would be considered a centaur.

Comet 38P passing within 1.6AU of Uranus in 2067.[4]


  1. ^ a b c d "JPL Small-Body Database Browser: 38P/Stephan-Oterma" (last observation: 1981-04-04; arc: 114.18 years). Jet Propulsion Laboratory. Retrieved 2009-05-07.
  2. ^ a b c d e MPC
  3. ^ a b c Seiichi Yoshida (2004-07-31). "38P/Stephan-Oterma". Seiichi Yoshida's Comet Catalog. Retrieved 2011-10-23.
  4. ^ a b "JPL Close-Approach Data: 38P/Stephan-Oterma" (last observation: 1981-04-04; arc: 114.18 years). Retrieved 2009-05-07.

External linksEdit

Numbered comets
38P/Stephan–Oterma Next