Menoetius (moon) facts for kids
Plot of the results of the multi-chord stellar occultation by 617 Patroclus and Menoetius
|
|
| Discovery | |
|---|---|
| Discovery date | 2001 |
| Designations | |
| Pronunciation | mi-NEE-shəs |
|
Named after
|
Menoetius (Greek mythology) |
| Adjectives | Menoetian) |
| Orbital characteristics | |
| 680±20 km 664.6 km |
|
| 102.8 h | |
| Satellite of | Patroclus |
| Physical characteristics | |
| Dimensions | 117 km × 108 km × 90 km |
|
Mean diameter
|
104±3 km |
Menoetius is a small space rock that orbits another asteroid called 617 Patroclus. It is the only known moon of Patroclus.
Contents
Discovering a Double Asteroid
In 2001, scientists made an exciting discovery. They found that Patroclus is actually a binary system. This means it's made up of two asteroids that are almost the same size.
Patroclus and Menoetius are part of a special group called Trojan asteroids. These asteroids share Jupiter's orbit around the Sun. There are at least 18 binary Trojan asteroids known so far.
How We Study Them
In 2006, astronomers used powerful telescopes at the Keck Observatory. They used a special system called "adaptive optics" to get very clear images. This helped them measure the orbit of Patroclus and Menoetius.
Scientists figured out that the two asteroids orbit around their shared center of mass. This is like the balance point between them. They complete one orbit in about 4.3 days. The distance between them is about 680 kilometers (420 miles).
Sizes of Patroclus and Menoetius
Early estimates in 2000 suggested the asteroids were about 106 km and 98 km across. Later, better measurements from the Keck Observatory refined these sizes.
Now, scientists believe Patroclus is about 122 km (76 miles) wide. Menoetius is slightly smaller, at about 112 km (70 miles) wide. They orbit each other every 103.5 hours, which is about 4.3 days.
Watching Them Pass in Front of a Star
On October 21, 2013, something cool happened. Both Patroclus and Menoetius passed in front of a distant star. This event is called an occultation.
A team of 41 observers across the USA watched this event. Their observations helped confirm the orbital distance between the two asteroids as 664.6 km. They also helped get more precise sizes. Patroclus, the slightly larger one, is like a sphere 113 km (70 miles) across. Menoetius, the smaller one, is like a sphere 104 km (65 miles) across.
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 impression of the Patroclus-Menoetius binary system
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Artist's impression of the Lucy spacecraft flying past the Patroclus-Menoetius system
