← Back to dex - Large body (100-500 km) +12
- Darker than charcoal +10
- Notably bright (low H) +8
- Has a proper name +8
- Carbonaceous — as old as the solar system +6
- Asteroid +1
- Main-belt asteroid +1
Total score 46
4 more points to reach Epic.
Badges
- 🪨 Asteroid · +1
- 🗿 Large body (100-500 km) · +12
- 💡 Notably bright (low H) · +8
- 🏷️ Has a proper name · +8
- 🥌 Main-belt asteroid · +1
- 🕶️ Darker than charcoal · +10
- 🖤 Carbonaceous — as old as the solar system · +6
✨ 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 3.07 AU of the Sun — inside the orbit of Jupiter.
- 🔁 One lap. A single orbit around the Sun takes it about 5.6 years.
- 🥏 How far it roams. Its orbit swings between 3.07 and 3.21 AU from the Sun.
Sense of scale
- 🧱 Sense of scale. In everyday terms it is about 6.2× the length of Manhattan island.
- 🚶 Walk around it. Walking its equator at a steady pace, eight hours a day, would take about 10.4 days.
By the numbers
- 📐 Size. Roughly 133 km across.
What's in a name
- 🏷️ Named. Notable enough to have earned a proper name, not just a catalogue number.
Properties
- albedo
- 0.0492
- aphelion au
- 3.21
- designation
- 147
- diameter km
- 132.93
- eccentricity
- 0.0218
- full name
- 147 Protogeneia (A875 NA)
- h mag
- 8.72
- inclination
- 1.93
- mean motion deg day
- 0.1774
- moid au
- 2.06
- name
- Protogeneia
- named
- yes
- orbit class
- MBA
- perihelion au
- 3.068
- rotation period h
- 7.8528
- semi major au
- 3.137
- spec taxonomy
- C
- spect
- C
About Protogeneia
Protogeneia is a rare asteroid. It has spectral type C and swings within 3.068 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, Protogeneia 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 Protogeneia is a rare asteroid
Protogeneia scores 46 points on Spacedle's rarity scale, which places it in the rare tier. Another 4 points would lift it into a rarer tier.
That score comes from 7 science badges — Asteroid, Large body (100-500 km), Notably bright (low H), Has a proper name, Main-belt asteroid, Darker than charcoal and Carbonaceous — as old as the solar system — 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.