About P/2021 R8 (Sheppard)
P/2021 R8 (Sheppard) is a rare comet. It swings within 2.131 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
P/2021 R8 (Sheppard)
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 2.13 AU of the Sun — inside the orbit of Jupiter.
- One lap. A single orbit around the Sun takes it about 5.2 years.
- How far it roams. Its orbit swings between 2.13 and 3.91 AU from the Sun.
Standing on it
- Sunlight there. Even at its closest the sunlight is only about 22% as strong as Earth's.
- 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
- 3.91
- designation
- 2021 R8
- eccentricity
- 0.294
- full name
- P/2021 R8 (Sheppard)
- inclination
- 2.2
- mean motion deg day
- 0.1879
- moid au
- 1.13
- name
- P/2021 R8 (Sheppard)
- named
- yes
- orbit class
- ETc
- perihelion au
- 2.131
- semi major au
- 3.019
How to see it
Like any astronomical target, P/2021 R8 (Sheppard) 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 P/2021 R8 (Sheppard) is a rare comet
P/2021 R8 (Sheppard) 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.