15 Eunomia facts for kids
15 Eunomia is a very large asteroid found in the inner part of the asteroid belt. It is the biggest of the stony asteroids, known as S-type asteroids. Eunomia is also one of the top 12 largest asteroids in the entire Main Belt. It is the main and biggest member of a group of asteroids called the Eunomia family.
| Discovery | |
|---|---|
| Discovered by | Annibale de Gasparis |
| Discovery date | July 29, 1851 |
| Designations | |
| none | |
| Main belt, (Eunomia family) | |
| Orbital characteristics | |
| Epoch June 14, 2006 (JD 2453900.5) | |
| Aphelion | 469.429 Gm (3.138 AU) |
| Perihelion | 321.429 Gm (2.149 AU) |
| 395.429 Gm (2.643 AU) | |
| Eccentricity | 0.187 |
| 1569.687 d (4.30 a) | |
|
Average orbital speed
|
18.16 km/s |
| 286.102° | |
| Inclination | 11.738° |
| 293.273° | |
| 97.909° | |
| Physical characteristics | |
| Dimensions | 330×245×205 |
| Mass | 3.26±0.12×1019 kg |
|
Mean density
|
3.8±0.7 g/cm³ |
| 0.08 m/s² | |
| 0.16 km/s | |
| 0.2535 d (6.083 h) | |
| Albedo | 0.209 (geometric) |
| Temperature | ~166 K max: 260 K (-13 °C) |
|
Spectral type
|
S-type asteroid |
| 7.9 to 11.24 | |
| 5.28 | |
| 0.29" to 0.085" | |
An Italian astronomer named Annibale de Gasparis discovered Eunomia on July 29, 1851. He named it after Eunomia, a goddess from Greek mythology. She was one of the Horae (Hours), who represented order and law.
What Makes Eunomia Special?
Eunomia is the largest S-type asteroid. This means it is made mostly of stony materials. Because of its size, scientists have studied it quite a bit.
- Eunomia holds more than one percent of the total mass of the entire main asteroid belt.
- It looks like a stretched, but mostly round, object.
- Scientists once thought it might be two objects orbiting each other, but this idea was later disproven.
- Eunomia spins backward compared to most planets. Its axis is tilted quite a lot, about 165 degrees.
What Is Eunomia Made Of?
Like other asteroids in its family, Eunomia's surface is made of silicate minerals. It also contains some nickel-iron metal. Its surface is quite bright.
- Scientists have found calcium-rich pyroxenes and olivine on its surface.
- These are common minerals found in rocks on Earth.
- Using special tools, scientists have seen that different parts of Eunomia's surface have different materials.
Observing Eunomia
Eunomia has passed in front of stars three times. This event is called an occultation. It helps scientists learn more about the asteroid's size and shape.
- When Eunomia is brightest, it can be seen with a good pair of binoculars.
- It shines about as brightly as Titan, which is Saturn's largest moon.
See also
In Spanish: (15) Eunomia para niños
