Frost line ( astrophysics ) - wikipedia Frost line ( astrophysics ) This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( December 2009 ) In astronomy or planetary science, the frost line, also known as the snow line or ice line, is the particular distance in the solar nebula from the central protostar where it is cold enough for volatile compounds such as water, ammonia, methane, carbon dioxide, carbon monoxide to condense into solid ice grains. This condensation temperature depends on the volatile substance and the partial pressure of vapor in the protostar nebula. The actual temperature and distance for the snow line of water ice depend on the physical model used to calculate it and on the theoretical solar nebula model : 170 K at 2.7 AU ( Hayashi, 1981 ) 143 K at 3.2 AU to 150 K at 3 AU ( Podolak and Zucker, 2010 ) 3.1 AU ( Martin and Livio, 2012 ) ≈ 150 K for μm - size grains and ≈ 200 K for km - size bodies ( D'Angelo and Podolak, 2015 ) The radial position of the condensation / evaporation front varies over time, as the nebula evolves. Occasionally, the term snow line is also used to represent the present distance at which water ice can be stable ( even under direct sunlight ). This current snow line distance is different from the formation snow line distance during the formation of the Solar System, and approximately equals 5 AU. The reason for the difference is that during the formation of the Solar System, the solar nebula was an opaque cloud where temperatures were lower close to the Sun, and the Sun itself was less energetic. After formation, the ice got buried by infalling dust and it has remained stable a few meters below the surface. If ice within 5 AU is exposed, e.g. by a crater, then it sublimates on short timescales. However, out of direct sunlight ice can remain stable on the surface of asteroids ( and the Moon ) if it is located in permanently shadowed craters, where temperature may remain very low over the age of the Solar System ( e.g. 30 -- 40 K on the Moon ). Observations of the asteroid belt, located between Mars and Jupiter, suggest that the water snow line during formation of the Solar System was located within this region. The outer asteroids are icy C - class objects ( e.g. Abe et al. 2000 ; Morbidelli et al. 2000 ) whereas the inner asteroid belt is largely devoid of water. This implies that when planetesimal formation occurred the snow line was located at around 2.7 AU from the Sun. For example, the dwarf planet Ceres with semi-major axis of 2.77 AU lies almost exactly on the lower estimation for water snow line during the formation of the Solar System. Ceres appears to have an icy mantle and may even have a water ocean below the surface. Each volatile substance has its own snow line, e.g. carbon monoxide and nitrogen, so it is important to always specify which material 's snow line is meant. A tracer gas may be used for materials that are difficult to detect ; for example diazenylium for carbon monoxide. The lower temperature in the nebula beyond the frost line makes many more solid grains available for accretion into planetesimals and eventually planets. The frost line therefore separates terrestrial planets from giant planets in the Solar System. However, giant planets have been found inside the frost line around several other stars ( so - called hot Jupiters ). They are thought to have formed outside the frost line, and later migrated inwards to their current positions. Earth, which lies less than a quarter of the distance to the frost line but is not a giant planet, has adequate gravitation for keeping methane, ammonia, and water vapor from escaping it. Methane and ammonia are rare in the Earth 's atmosphere only because of their instability in an oxygen - rich atmosphere that results from life forms ( largely green plants ) whose biochemistry suggests plentiful methane and ammonia at one time, but of course liquid water and ice, which are chemically stable in such an atmosphere, form much of the surface of Earth. Researchers Rebecca Martin and Mario Livio have proposed that asteroid belts may tend to form in the vicinity of the frost line, due to nearby giant planets disrupting planet formation inside their orbit. By analysing the temperature of warm dust found around some 90 stars, they concluded that the dust ( and therefore possible asteroid belts ) was typically found close to the frost line. The term is borrowed from the notion of `` frost line '' in soil science. See also Circumstellar habitable zone Nebular hypothesis Solar nebula References Jump up ^ `` Structure of the Solar Nebula, Growth and Decay of Magnetic Fields and Effects of Magnetic and Turbulent Viscosities on the Nebula by Chushiro Hayashi ''. Archived from the original on 2015 - 02 - 19. Jump up ^ Podolak, M. ; Zucker, S. ( 2004 ). `` A note on the snow line in protostellar accretion disks by M. PODOLAK and S. ZUCKER, 2010 ''. Meteoritics & Planetary Science. 39 ( 11 ) : 1859. Bibcode : 2004M&PS... 39.1859 P. doi : 10.1111 / j. 1945 - 5100.2004. tb00081. x. ^ Jump up to : Martin, Rebecca G. ; Livio, Mario ( 2012 ). `` On the Evolution of the Snow Line in Protoplanetary Discs by Rebecca G. Martin, Mario Livio ( STScI ) ''. Monthly Notices of the Royal Astronomical Society : Letters. 425 : L6. arXiv : 1207.4284. Bibcode : 2012MNRAS. 425L... 6M. doi : 10.1111 / j. 1745 - 3933.2012. 01290. x. Jump up ^ D'Angelo, G. ; Podolak, M. ( 2015 ). `` Capture and Evolution of Planetesimals in Circumjovian Disks ''. The Astrophysical Journal. 806 ( 1 ) : 29pp. arXiv : 1504.04364. Bibcode : 2015ApJ... 806... 203D. doi : 10.1088 / 0004 - 637X / 806 / 2 / 203. Jump up ^ Jewitt, D ; Chizmadia, L. ; Grimm, R. ; Prialnik, D ( 2007 ). `` Water in the Small Bodies of the Solar System ''. In Reipurth, B. ; Jewitt, D. ; Keil, K. Protostars and Planets V ( PDF ). University of Arizona Press. pp. 863 -- 878. ISBN 0 - 8165 - 2654 - 0. CS1 maint : Uses editors parameter ( link ) Jump up ^ McCord, T.B. ; Sotin, C. ( 2005 - 05 - 21 ). `` Ceres : Evolution and current state ''. Journal of Geophysical Research : Planets. 110 ( E5 ) : E05009. Bibcode : 2005JGRE... 110.5009 M. doi : 10.1029 / 2004JE002244. Retrieved 2015 - 03 - 07. Jump up ^ O'Brien, D.P. ; Travis, B.J. ; Feldman, W.C. ; Sykes, M.V. ; Schenk, P.M. ; Marchi, S. ; Russell, C.T. ; Raymond, C.A. ( March 2015 ). `` The Potential for Volcanism on Ceres due to Crustal Thickening and Pressurization of a Subsurface Ocean '' ( PDF ). 46th Lunar and Planetary Science Conference. p. 2831. Retrieved 1 March 2015. Jump up ^ Qi, Chunhua ; Oberg, Karin I. ; Wilner, David J. ; d'Alessio, Paola ; Bergin, Edwin ; Andrews, Sean M. ; Blake, Geoffrey A. ; Hogerheijde, Michiel R. ; van Dishoeck, Ewine F. ( 2013 ). `` Imaging of the CO Snow Line in a Solar Nebula Analog by Chunhua Qi, Karin I. Oberg, et al ''. Science. 341 ( 6146 ) : 630. arXiv : 1307.7439. Bibcode : 2013Sci... 341... 630Q. doi : 10.1126 / science. 1239560. PMID 23868917. Jump up ^ `` UltraCarbonaceous Antarctic micrometeorites, probing the Solar System beyond the nitrogen snow - line by E. Dartois, et al ''. Icarus. ScienceDirect. 224 : 243 -- 252. Bibcode : 2013Icar... 224... 243D. doi : 10.1016 / j. icarus. 2013.03. 002. Jump up ^ Kaufmann, William J. ( 1987 ). Discovering the Universe. W.H. Freeman and Company. p. 94. ISBN 0 - 7167 - 1784 - 0. Jump up ^ Chambers, John ( 2007 - 07 - 01 ). `` Planet Formation with Type I and Type II Migration ''. 38. AAS / Division of Dynamical Astronomy Meeting. Bibcode 2007DDA... 38.0604 C. Jump up ^ D'Angelo, Gennaro ; Durisen, Richard H. ; Lissauer, Jack J. ( December 2010 ). `` Giant Planet Formation ''. In Seager, Sara. Exoplanets. University of Arizona Press. pp. 319 -- 346. arXiv : 1006.5486. Bibcode : 2010exop. book... 319D. ISBN 978 - 0 - 8165 - 2945 - 2. Jump up ^ `` Asteroid Belts of Just the Right Size are Friendly to Life ''. Nasa. 1 November 2012. Retrieved 3 November 2012. External links Wikiquote has quotations related to : Frost line ( astrophysics ) The thermal structure and the location of the snow line in the protosolar nebula : axisymmetric models with full 3 - D radiative transfer by M. Min, C.P. Dullemond, M. Kama, C. Dominik On the Snow Line in Dusty Protoplanetary Disks by D.D. Sasselov and M. Lecar Retrieved from `` https://en.wikipedia.org/w/index.php?title=Frost_line_(astrophysics)&oldid=866332149 '' Categories : Planetary science Cold Hidden categories : CS1 maint : Uses editors parameter Articles needing additional references from December 2009 All articles needing additional references All articles with unsourced statements Articles with unsourced statements from March 2015 Talk About Wikipedia Català Čeština Deutsch Español Esperanto Français Italiano עברית Lëtzebuergesch Lietuvių Bahasa Melayu 日本 語 Norsk Polski Português Русский Suomi Українська 中文 10 more Edit links This page was last edited on 29 October 2018, at 18 : 33 ( UTC ). 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Question: where is the frost line in the solar system
Answer: approximately equals 5 AU