This object moves — fetching its current position…
Score breakdown
· 4 badges
18 pts · Common
Common22 pts → Uncommon
Notably bright (low H)+8
Has a proper name+8
Asteroid+1
Main-belt asteroid+1
Total score18
4 more points to reach Uncommon.
Badges
🪨Asteroid· +1
💡Notably bright (low H)· +8
🏷️Has a proper name· +8
🥌Main-belt asteroid· +1
✨ Trivia
What it actually is
🛸Its orbit family. A main-belt asteroid, one of millions circling between Mars and Jupiter. Despite the films, the belt is so empty that every spacecraft sent through it has crossed without aiming for anything.
🌞Closest approach. At its nearest it comes within 2.23 AU of the Sun — inside the orbit of Jupiter.
🔁One lap. A single orbit around the Sun takes it about 4.2 years.
🥏How far it roams. Its orbit swings between 2.23 and 2.99 AU from the Sun.
Sense of scale
🧱Sense of scale. In everyday terms it is roughly 4.6× the height of Mount Everest.
🚶Walk around it. Walking its equator at a steady pace, eight hours a day, would take about 3.2 days.
Standing on it
🥶Sunlight there. Even at its closest the sunlight is only about 20% as strong as Earth's.
By the numbers
📐Size. Roughly 40.8 km across.
Properties
albedo
0.202
aphelion au
2.99
designation
500
diameter km
40.828
eccentricity
0.1458
full name
500 Selinur (A903 BJ)
h mag
9.45
inclination
9.79
mean motion deg day
0.2335
moid au
1.25
name
Selinur
named
yes
orbit class
MBA
perihelion au
2.231
rotation period h
8.0111
semi major au
2.612
About Selinur
Selinur is a common asteroid. It swings within 2.231 AU of the Sun at perihelion.
A main-belt asteroid, one of millions circling between Mars and Jupiter. Despite the films, the belt is so empty that every spacecraft sent through it has crossed without aiming for anything.
How to see it
Like any astronomical target, Selinur 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 Selinur is a common asteroid
Selinur scores 18 points on Spacedle's rarity scale, which places it in the common tier. Another 4 points would lift it into a rarer tier.
That score comes from 4 science badges — Asteroid, Notably bright (low H), Has a proper name and Main-belt asteroid — 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.