About 501P/Rankin
501P/Rankin is a rare comet. It swings within 0.68 AU of the Sun at perihelion.
An Encke-type comet, on an unusually tight orbit that never even reaches out as far as Jupiter.
Rare comet 36 EP
501P/Rankin
Position computed live · sbdb
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Live ephemeris
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Score breakdown
· 3 badgesRare 50 pts → Epic
- Encke-type comet (never leaves Jupiter's reach) +22
- Has a proper name +8
- Comet +6
Total score 36
14 more points to reach Epic.
Badges
- Comet · +6
- Has a proper name · +8
- Encke-type comet (never leaves Jupiter's reach) · +22
Trivia
What it actually is
- Its orbit family. An Encke-type comet, on an unusually tight orbit that never even reaches out as far as Jupiter.
- Closest approach. At its nearest it comes within 0.68 AU of the Sun — inside the orbit of Venus.
- One lap. A single orbit around the Sun takes it about 3.3 years.
- How far it roams. Its orbit swings between 0.68 and 3.79 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
- 3.79
- designation
- 501P
- eccentricity
- 0.6957
- full name
- 501P/Rankin
- inclination
- 10.1
- mean motion deg day
- 0.2948
- moid au
- 0.0638
- name
- 501P/Rankin
- named
- yes
- orbit class
- ETc
- perihelion au
- 0.68
- semi major au
- 2.236
How to see it
Like any astronomical target, 501P/Rankin 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 501P/Rankin is a rare comet
501P/Rankin scores 36 points on Spacedle's rarity scale, which places it in the rare tier. Another 14 points would lift it into a rarer tier.
That score comes from 3 science badges — Comet, Has a proper name and Encke-type comet (never leaves Jupiter's reach) — 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.