About 38P/Stephan-Oterma
38P/Stephan-Oterma is an uncommon comet. It swings within 1.589 AU of the Sun at perihelion.
A Halley-type comet: 20 to 200 years per lap, on a steeply tilted orbit that reaches far beyond the planets.
Uncommon comet 30 EP
38P/Stephan-Oterma
Position computed live · sbdb
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Live ephemeris
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Score breakdown
· 3 badgesUncommon 34 pts → Rare
- Halley-type comet +16
- Has a proper name +8
- Comet +6
Total score 30
4 more points to reach Rare.
Badges
- Comet · +6
- Has a proper name · +8
- Halley-type comet · +16
Trivia
What it actually is
- Its orbit family. A Halley-type comet: 20 to 200 years per lap, on a steeply tilted orbit that reaches far beyond the planets.
- Closest approach. At its nearest it comes within 1.59 AU of the Sun — inside the orbit of Jupiter.
- One lap. A single orbit around the Sun takes it about 37.9 years.
- How far it roams. Its orbit swings between 1.59 and 20.99 AU from the Sun.
Standing on it
- Growing a tail. Once inside roughly the orbit of Mars the ice starts turning straight to gas, blowing out the coma and tail that make a comet a comet.
- Tail. Its tail always points away from the Sun, never trailing behind its motion — it is blown, not dragged.
By the numbers
- Made of. A comet is a dirty snowball: water ice, frozen carbon dioxide and dust, held together loosely enough that some simply crumble when the Sun warms them.
What's in a name
- Named. Notable enough to have earned a proper name, not just a catalogue number.
Properties
- aphelion au
- 20.99
- designation
- 38P
- eccentricity
- 0.8593
- full name
- 38P/Stephan-Oterma
- inclination
- 18.35
- mean motion deg day
- 0.026
- moid au
- 0.605
- name
- 38P/Stephan-Oterma
- named
- yes
- orbit class
- HTC
- perihelion au
- 1.589
- semi major au
- 11.29
How to see it
Like any astronomical target, 38P/Stephan-Oterma is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. Because it moves against the background stars, the live position panel on this page tracks where it is right now. The visibility panel above works out tonight's viewing window for your saved location.
Why 38P/Stephan-Oterma is an uncommon comet
38P/Stephan-Oterma scores 30 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 4 points would lift it into a rarer tier.
That score comes from 3 science badges — Comet, Has a proper name and Halley-type comet — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.