About Troilus
Troilus is a rare asteroid. It has spectral type FCU and swings within 4.77 AU of the Sun at perihelion.
Locked in a gravitational sweet spot 60° ahead of or behind a much larger body, shepherded there for billions of years.
Rare asteroid 49 EP
Troilus
Position computed live · sbdb
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Live ephemeris
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Score breakdown
· 6 badgesRare 50 pts → Epic
- Large body (100-500 km) +12
- Trojan +10
- Darker than charcoal +10
- Notably bright (low H) +8
- Has a proper name +8
- Asteroid +1
Total score 49
1 more point to reach Epic.
Badges
- Asteroid · +1
- Trojan · +10
- Large body (100-500 km) · +12
- Notably bright (low H) · +8
- Has a proper name · +8
- Darker than charcoal · +10
Trivia
What makes it special
- Trojan. Locked in a gravitational sweet spot 60° ahead of or behind a much larger body, shepherded there for billions of years.
What it actually is
- Its orbit family. A Jupiter trojan, parked in a gravitational sweet spot 60° ahead of or behind Jupiter and shepherded there for billions of years. There may be as many trojans as there are main-belt asteroids.
- Closest approach. At its nearest it comes within 4.77 AU of the Sun — inside the orbit of Jupiter.
- One lap. A single orbit around the Sun takes it about 12 years.
- How far it roams. Its orbit swings between 4.77 and 5.74 AU from the Sun.
Sense of scale
- Sense of scale. In everyday terms it is about 4.7× the length of Manhattan island.
- Walk around it. Walking its equator at a steady pace, eight hours a day, would take about 7.9 days.
By the numbers
- Size. Roughly 100 km across.
Properties
- albedo
- 0.041
- aphelion au
- 5.74
- designation
- 1208
- diameter km
- 100.477
- eccentricity
- 0.0924
- full name
- 1208 Troilus (1931 YA)
- h mag
- 9.03
- inclination
- 33.54
- mean motion deg day
- 0.0818
- moid au
- 3.88
- name
- Troilus
- named
- yes
- orbit class
- TJN
- perihelion au
- 4.77
- rotation period h
- 56.17
- semi major au
- 5.255
- spec taxonomy
- FCU
- spect
- FCU
- trojan
- yes
How to see it
Like any astronomical target, Troilus 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 Troilus is a rare asteroid
Troilus scores 49 points on Spacedle's rarity scale, which places it in the rare tier. Another 1 point would lift it into a rarer tier.
That score comes from 6 science badges — Asteroid, Trojan, Large body (100-500 km), Notably bright (low H), Has a proper name and Darker than charcoal — 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.