Iron planet
Encyclopedia
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An iron planet is a type of planet that consists primarily of an iron
-rich core with little or no mantle
. Mercury
is the largest celestial body of this type in our solar system, but larger iron-rich exoplanets may exist.
whose rocky mantles were stripped away by giant impacts. Some are believed to consist of diamond fields. Current planet formation models predict iron-rich planets will form in close-in orbits or orbiting massive stars where the
protoplanetary disk
presumably consists of iron-rich material.
Such planets would have no plate tectonics
or strong magnetic field
as they cool rapidly after formation.
An iron planet is a type of planet that consists primarily of an iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
-rich core with little or no mantle
Mantle (geology)
The mantle is a part of a terrestrial planet or other rocky body large enough to have differentiation by density. The interior of the Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a highly viscous layer between the crust and the outer core....
. Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
is the largest celestial body of this type in our solar system, but larger iron-rich exoplanets may exist.
Origin
Iron-rich planets may be the remnants of normal metal/silicate rocky planetsTerrestrial planet
A terrestrial planet, telluric planet or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun...
whose rocky mantles were stripped away by giant impacts. Some are believed to consist of diamond fields. Current planet formation models predict iron-rich planets will form in close-in orbits or orbiting massive stars where the
protoplanetary disk
Protoplanetary disk
A protoplanetary disk is a rotating circumstellar disk of dense gas surrounding a young newly formed star, a T Tauri star, or Herbig Ae/Be star...
presumably consists of iron-rich material.
Characteristics
Iron-rich planets are smaller and more dense than other types of planets of comparable mass.Such planets would have no plate tectonics
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...
or strong magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
as they cool rapidly after formation.
See also
- IronIronIron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
- Carbon planetCarbon planetA carbon planet, also referred to as a diamond planet or carbide planet, is a theoretical type of planet proposed by Marc Kuchner that could form if protoplanetary discs are carbon-rich and oxygen-poor. According to planetary science, it would develop differently from Earth, Mars and Venus, planets...
- Extrasolar planetExtrasolar planetAn extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
- Terrestrial planetTerrestrial planetA terrestrial planet, telluric planet or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun...
- Dwarf planetDwarf planetA dwarf planet, as defined by the International Astronomical Union , is a celestial body orbiting the Sun that is massive enough to be spherical as a result of its own gravity but has not cleared its neighboring region of planetesimals and is not a satellite...