617 Patroclus facts for kids
| Discovery | |
|---|---|
| Discoverer | August Kopff |
| Discovery date | October 17, 1906 |
| Alternate designations |
1906 VY; 1941 XC; 1962 NB |
| Category | Jupiter Trojan |
| Orbital elements | |
|
|
|
| Eccentricity (e) | 0.138 |
| Semi-major axis (a) | 5.228 AU |
| Perihelion (q) | 4.506 AU
|
| Aphelion (Q) | 5.950 AU |
| Orbital period (P) | 4365.7 d (11.95 a) |
| Mean orbital speed | ??? |
| Inclination (i) | 22.03° |
| Longitude of the ascending node (Ω) |
44.37° |
| Argument of perihelion (ω) |
307.81° |
| Mean anomaly (M) | 149.94° |
| Physical characteristics | |
| Dimensions | 122 km and 112 km |
| Mass | 1.36×1018 kg |
| Density | 0.8 g/cm³ |
| Surface gravity | ??? |
| Escape velocity | ??? |
| Rotation period | >4.283±0.004 days |
| Spectral class | P-type |
| Absolute magnitude | 8.19 |
| Albedo (geometric) | 0.047 |
| Mean surface temperature |
110 K |
617 Patroclus is a special space object. It's not just one thing, but two objects orbiting each other! These two objects are almost the same size. Patroclus is a type of asteroid called a Trojan. This means it shares its orbit around the Sun with the giant planet Jupiter.
It was discovered in 1906 by August Kopff. Patroclus was only the second Trojan asteroid ever found. Scientists now think these objects might be icy comets, not just rocky asteroids.
Contents
Patroclus's Orbit Around the Sun
Patroclus orbits the Sun in a special spot near Jupiter. This spot is called a Lagrangian point, or L5. It's like a stable parking spot in space.
This area is known as the 'Trojan node'. It's named after one side in the famous Trojan War stories. The other side is called the 'Greek node'.
It's interesting that Patroclus is named after a Greek hero, even though it's in the 'Trojan' group. The rules for naming these asteroids were made after Patroclus got its name. Another example is Hektor, a Trojan hero, who is in the 'Greek' group.
Two Objects in One: A Binary System
In 2001, scientists made an exciting discovery: Patroclus is actually two objects! They are almost the same size and orbit each other.
In 2006, a team of astronomers used powerful telescopes to study them. They found that the two objects orbit their shared center of mass every 4.283 days. They are about 680 kilometers apart.
The slightly bigger object is 122 kilometers wide. It kept the name Patroclus. The smaller object is 112 kilometers wide. It was named Menoetius. Menoetius was Patroclus's father in the old stories. Its full name is (617) Patroclus I Menoetius.
What Patroclus and Menoetius Are Made Of
Scientists have measured the density of the Patroclus system. It's about 0.8 grams per cubic centimeter. This is less than water! It's also much lighter than typical rock.
Because of this low density, researchers think Patroclus and Menoetius are more like comets than rocky asteroids. They might be made of ice and dust.
Many Trojan asteroids are thought to be small planetesimals. These are tiny building blocks of planets. They might have been captured in Jupiter's orbit billions of years ago. This happened when the giant planets moved around in the early solar system.
- Learn more about the cometary origin of Patroclus
Images for kids
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Hubble images of Patroclus and Menoetius orbiting each other, from May to June 2017
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Artist's idea of Patroclus and Menoetius orbiting around their center of mass, sometimes blocking each other
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Artist's idea of the Patroclus-Menoetius binary system
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Animation of Lucy's path around the Sun Lucy · Sun · Earth · 52246 Donaldjohanson · 3548 Eurybates · 21900 Orus · 617 Patroclus
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Artist's idea of the Lucy spacecraft flying past the Patroclus-Menoetius system
See also
In Spanish: (617) Patroclus para niños
