C-type asteroid facts for kids

C-type asteroids are a very common type of asteroid. They are mostly made of materials like carbonates. About 75% of all known asteroids are C-types. You find even more of them in the outer part of the main asteroid belt, beyond 2.7 AU from the Sun. It's possible there are even more C-type asteroids than we know. This is because they are very dark, making them hard to spot compared to other types.

What Makes Them Special?

C-type asteroids are quite similar to a type of meteorite called carbonaceous chondrites. These meteorites have a chemical makeup much like the Sun and the early cloud of gas and dust that formed our Solar System. The main difference is that C-type asteroids and these meteorites don't have light elements like hydrogen and helium.

These asteroids often contain minerals that have water inside them. This is called "hydrated" minerals.

How Dark Are They?

C-type asteroids are very dark. Their albedo (how much light they reflect) is usually between 0.03 and 0.10. This means they reflect only a small amount of sunlight.

Because they are so dark, C-type asteroids are hard to see. You can often see some brighter S-type asteroids with binoculars when they are closest to Earth. But even the largest C-type asteroids need a small telescope to be seen. For example, 324 Bamberga is a potentially bright C-type. However, its unusual orbit means it rarely gets bright enough to be easily seen.

Their Light Signature

Scientists study the light that comes from asteroids. This is called their spectrum. C-type asteroids have a specific light signature. They absorb a good amount of ultraviolet light at certain wavelengths.

At longer wavelengths, their spectrum is quite smooth but looks a bit reddish. They also show a special "water" feature around 3 micrometers. This feature is a sign that there might be water-containing minerals on the asteroid.

Biggest C-types

The largest asteroid that is definitely a C-type is 10 Hygiea. Some classification systems also place 1 Ceres, the biggest asteroid of all, in this group. This is because these systems don't have a separate category for G-type asteroids.

Images for kids

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  253 Mathilde, a C-type asteroid

See also

In Spanish: Asteroide de tipo C para niños