About Alcathous
Alcathous is an epic asteroid. It has spectral type D and swings within 4.822 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.
Epic asteroid 61 EP
Alcathous
Position computed live · sbdb
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Live ephemeris
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Score breakdown
· 7 badgesEpic 78 pts → Anomaly
- Large body (100-500 km) +12
- Primitive outer-belt type +12
- Trojan +10
- Darker than charcoal +10
- Notably bright (low H) +8
- Has a proper name +8
- Asteroid +1
Total score 61
17 more points to reach Anomaly.
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
- Primitive outer-belt type · +12
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 4.82 AU of the Sun — inside the orbit of Jupiter.
- One lap. A single orbit around the Sun takes it about 11.7 years.
- How far it roams. Its orbit swings between 4.82 and 5.51 AU from the Sun.
Sense of scale
- Sense of scale. In everyday terms it is about 5.3× the length of Manhattan island.
- Walk around it. Walking its equator at a steady pace, eight hours a day, would take about 8.9 days.
By the numbers
- Size. Roughly 114 km across.
Properties
- albedo
- 0.048
- aphelion au
- 5.51
- designation
- 2241
- diameter km
- 113.682
- eccentricity
- 0.0671
- full name
- 2241 Alcathous (1979 WM)
- h mag
- 8.52
- inclination
- 16.63
- mean motion deg day
- 0.0839
- moid au
- 3.86
- name
- Alcathous
- named
- yes
- orbit class
- TJN
- perihelion au
- 4.822
- rotation period h
- 7.689
- semi major au
- 5.168
- spec taxonomy
- D
- spect
- D
- trojan
- yes
How to see it
Like any astronomical target, Alcathous 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 Alcathous is an epic asteroid
Alcathous scores 61 points on Spacedle's rarity scale, which places it in the epic tier. Another 17 points would lift it into a rarer tier.
That score comes from 7 science badges — Asteroid, Trojan, Large body (100-500 km), Notably bright (low H), Has a proper name, Darker than charcoal and Primitive outer-belt type — 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.