View source for Astronomy:Refractory (planetary science)

{{short description|Materials with high condensation temperatures, contrasted with volatiles}}
In [[Astronomy:Planetary science|planetary science]], any material that has a relatively high equilibrium condensation temperature is called '''refractory'''.<ref name=Ross>{{cite book
|title=Solar system evolution: a new perspective : an inquiry into the chemical composition, origin, and evolution of the solar system
|url=https://books.google.com/books?id=R3QKq4K0jIEC&q=refractory+ice+rock+gas
|publisher={{wipe|Cambridge University Press}}
|date=2001
|pages=73–75
|last=Taylor
|first=Stuart Ross
|isbn= 978-0-521-64130-2
}}</ref> The opposite of refractory is [[Earth:Volatile (astrogeology)|volatile]].

The refractory group includes elements and compounds like metals and silicates (commonly termed rocks) which make up the bulk of the mass of the [[Astronomy:Terrestrial planet|terrestrial planet]]s and asteroids in the inner belt. A fraction of the mass of other asteroids, giant planets, their moons and [[Astronomy:Trans-Neptunian object|trans-Neptunian object]]s is also made of refractory materials.<ref name=Beatty>{{cite book
|title=The new solar system
|url=https://books.google.com/books?id=6uqfPYBdy0cC&q=rock+gas+ice+asteroid
|publisher=Cambridge University Press
|date=1999
|pages=314–315
|last=Beatty
|first=J. Kelly
|editor=Beatty, J. Kelly
|editor2=Petersen, Carolyn Collins
|editor3=Chaikin, Andrew 
|isbn= 978-0-521-64587-4
}}</ref>

==Classification==

The [[Chemistry:Chemical element|elements]] can be divided into several categories:

{| class="wikitable"
|'''Category'''
|'''Condensation temperatures'''
|'''Elements'''
|-
|Super-refractory
|higher than 1700 K
|Re, Os, W, Zr and Hf

|-
|Refractory
|between 1500 and 1700 K
|Al, Sc, Ca, Ti, Th, Lu, Tb, Dy, Ho, Er, Tm, Ir, Ru, Mo, U, Sm, Nd and  La

|-
|Moderately refractory
|1300 to 1500 K
|Nb, Be, V, Ce, Yb, Pt, Fe, Co, Ni, Pd, Mg, Eu, Si, Cr

|-
|Moderately volatile
|1100–1300 K
|Au, P, Li, Sr, Mn, Cu and Ba

|-
|Volatile
|700–1100 K
|Rb, Cs, K, Ag, Na, B, Ga, Sn, Se and S
|-
|Very volatile
|less than 700 K
|Zn, Pb, In, Bi and Tl
|}<ref name=Ross/>

The condensation temperatures are the temperatures at which 50% of the element will be in the form of a solid (rock) under a pressure of 10<sup>−4</sup> [[Bar (unit)|bar]]. However, slightly different groups and temperature ranges are used sometimes. Refractory material are also often divided into refractory [[Chemistry:Goldschmidt classification#Lithophile elements|lithophile elements]] and refractory [[Chemistry:Goldschmidt classification#Siderophile elements|siderophile elements]].<ref name=Davis>{{cite book
|title=Meteorites, comets, and planets
|url=https://books.google.com/books?id=kYtksEUxw0oC&q=refractory+solar+volatile
|publisher=[[Company:Elsevier|Elsevier]]
|date=2005
|pages=45–47
|last=Davis
|first=Andrew M.
|author2=Turekian, Karl K. 
 |editor= Davis, Andrew M. 
 |editor2= Holland, Heinrich D. 
 |editor3= Turekian, Karl K. 
|isbn= 978-0-08-044720-9
}}</ref>

==References==
{{Reflist}}


[[Category:Planetary geology]]
[[Category:Petrology]]
[[Category:Volcanology]]
[[Category:Astrobiology]]
[[Category:Prebiotic chemistry]]

{{Sourceattribution|Refractory (planetary science)}}