A coreless planet is a hypothetical type of terrestrial planet that has no metallic core and is thus effectively a giant rocky mantle. It can be formed in cooler regions and far from the star.
According to a 2008 paper by Sara Seager and Linda Elkins-Tanton,[1] there are probably two ways in which a coreless planet may form.
In the first, the planet accretes from chondrite-like fully oxidized water-rich material, where all the metallic iron is bound into silicate mineral crystals. Such planets may form in cooler regions farther from the central star.
In the second, the planet accretes from both water-rich and iron metal-rich material. However, the metal iron reacts with water to form iron oxide and release hydrogen before differentiation of a metal core has taken place. Provided the iron droplets are well mixed and small enough (<1 centimeter), the predicted end result is that the iron is oxidized and trapped in the mantle, unable to form a core.
Magnetic fieldedit
Earth's magnetic field results from its flowing liquid metallic core, according to the dynamo theory, but in super-Earths the mass can produce high pressures with large viscosities and high melting temperatures which could prevent the interiors from separating into different layers and so result in undifferentiated coreless mantles. Magnesium oxide, which is rocky on Earth, can be liquid at the pressures and temperatures found in super-Earths and could generate a magnetic field in the mantles of super-Earths.[2][3]
Characteristicsedit
The predicted sizes of coreless and cored planets are similar within a few percent, which makes it difficult to interpret the interior composition of exoplanets based on measured planetary masses and radii.[4]
^Super-Earths Get Magnetic 'Shield' from Liquid Metal, Charles Q. Choi, SPACE.com, November 22, 2012 02:01pm ET,
^The Effect of Lower Mantle Metallization on Magnetic Field Generation in Rocky Exoplanets, Ryan Vilim, Sabine Stanley, Linda Elkins-Tanton, (Submitted on 25 Apr 2013)
^A Framework for Quantifying the Degeneracies of Exoplanet Interior Compositions, L. A. Rogers, S. Seager, (Submitted on 16 Dec 2009 (v1), last revised 4 Jun 2010 (this version, v2))
The Role of Carbon in Extrasolar Planetary Geodynamics and Habitability, Cayman T. Unterborn, Jason E. Kabbes, Jeffrey S. Pigott, Daniel R. Reaman, Wendy R. Panero, (Submitted on 31 October 2013 (v1), last revised 9 November 2013 (this version, v3))
coreless, planet, confused, with, hollow, earth, coreless, planet, hypothetical, type, terrestrial, planet, that, metallic, core, thus, effectively, giant, rocky, mantle, formed, cooler, regions, from, star, contents, origin, magnetic, field, characteristics, . Not to be confused with Hollow Earth A coreless planet is a hypothetical type of terrestrial planet that has no metallic core and is thus effectively a giant rocky mantle It can be formed in cooler regions and far from the star Contents 1 Origin 2 Magnetic field 3 Characteristics 4 See also 5 ReferencesOrigin editAccording to a 2008 paper by Sara Seager and Linda Elkins Tanton 1 there are probably two ways in which a coreless planet may form In the first the planet accretes from chondrite like fully oxidized water rich material where all the metallic iron is bound into silicate mineral crystals Such planets may form in cooler regions farther from the central star In the second the planet accretes from both water rich and iron metal rich material However the metal iron reacts with water to form iron oxide and release hydrogen before differentiation of a metal core has taken place Provided the iron droplets are well mixed and small enough lt 1 centimeter the predicted end result is that the iron is oxidized and trapped in the mantle unable to form a core Magnetic field editEarth s magnetic field results from its flowing liquid metallic core according to the dynamo theory but in super Earths the mass can produce high pressures with large viscosities and high melting temperatures which could prevent the interiors from separating into different layers and so result in undifferentiated coreless mantles Magnesium oxide which is rocky on Earth can be liquid at the pressures and temperatures found in super Earths and could generate a magnetic field in the mantles of super Earths 2 3 Characteristics editThe predicted sizes of coreless and cored planets are similar within a few percent which makes it difficult to interpret the interior composition of exoplanets based on measured planetary masses and radii 4 See also editChthonian planetReferences edit Seager S L Elkins Tanton 2008 Coreless Terrestrial Exoplanets Astrophysical Journal 688 1 628 635 arXiv 0808 1908 Bibcode 2008ApJ 688 628E doi 10 1086 592316 Super Earths Get Magnetic Shield from Liquid Metal Charles Q Choi SPACE com November 22 2012 02 01pm ET The Effect of Lower Mantle Metallization on Magnetic Field Generation in Rocky Exoplanets Ryan Vilim Sabine Stanley Linda Elkins Tanton Submitted on 25 Apr 2013 A Framework for Quantifying the Degeneracies of Exoplanet Interior Compositions L A Rogers S Seager Submitted on 16 Dec 2009 v1 last revised 4 Jun 2010 this version v2 The Role of Carbon in Extrasolar Planetary Geodynamics and Habitability Cayman T Unterborn Jason E Kabbes Jeffrey S Pigott Daniel R Reaman Wendy R Panero Submitted on 31 October 2013 v1 last revised 9 November 2013 this version v3 Portals nbsp Astronomy nbsp Space Retrieved from https en wikipedia org w index php title Coreless planet amp oldid 1218798237, wikipedia, wiki, book, books, library,
