Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso


  • François RaulinEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_1588-4



“Tholins” designates the solid refractory organics that are produced during the irradiation of gases or ice mixtures of simple compounds by a variety of energy sources, which are also of astrophysical significance.


The word tholins was coined by Carl Sagan and Bishun Khare in the late 1970s (Sagan and Khare 1979), when they realized that in many laboratory experiments, simulating the chemical evolution of astrophysical environments starting from simple organic compounds, nonvolatile complex macromolecular organics were systematically formed. They proposed in particular that tholins play a key role in the organic chemistry of interstellar grains and gas. Since these products often looked like mud or tar, Sagan and Khare decided to call them “tholins,” which comes from the Greek word “tholos,” meaning “muddy” or alternatively “domed.”


Tholins are produced in a large variety of experiments simulating the complexification of...


Khare Laboratory simulation experiment Plasma experiment Refractory organics Sagan Solid organic product Titan’s aerosols Titan’s haze 
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References and Further Reading

  1. Bernard JM, Quirico E, Brissaud O et al (2006) Reflectance spectra and chemical structure of Titan’s tholins: application to the analysis of Cassini-Huygens observations. Icarus 185:301–307CrossRefADSGoogle Scholar
  2. Biemann K (2006) Astrochemistry: complex organic matter in Titan’s aerosols? Nature 444:E6CrossRefADSGoogle Scholar
  3. Cable M, Horst S, Hodyss R, Beauchamp P, Smith M, Willis P (2012) Titan tholins: simulating Titan organic chemistry in the Cassini-Huygens era. Chem Rev 112(3):1882–1909CrossRefGoogle Scholar
  4. Coll P, Navarro-González R, Szopa C, Poch O, Ramírez SI, Coscia D, Raulin F, Cabane M, Buch A, Israël G (2013) Can laboratory tholins mimic the chemistry producing Titan’s aerosols? A review in light of ACP experimental results. Planet Space Sci 77:91–103CrossRefADSGoogle Scholar
  5. Imanaka H, Smith MA (2010) Formation of nitrogenated organic aerosols in the Titan upper atmosphere. Proc Natl Acad Sci U S A 107:12423–12428CrossRefADSGoogle Scholar
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  9. Khare BN, Sagan C, Arakawa ET et al (1984) Optical constants of organic tholins produced in a simulated Titanian atmosphere: from soft X-rays to microwave frequencies. Icarus 60:127–137CrossRefADSGoogle Scholar
  10. Khare BN, Sagan C, Ogino H et al (1986) Amino acids derived from Titan tholins. Icarus 68:176–184CrossRefADSGoogle Scholar
  11. Miller SL (1953) A production of amino acids under possible primitive Earth conditions. Science 117:528–529CrossRefADSGoogle Scholar
  12. Neish CD, Somogyi Á, Smith MA (2010) Titan’s primordial soup: formation of amino acids via low-temperature hydrolysis of tholins. Astrobiology 10:337–347CrossRefADSGoogle Scholar
  13. Ramirez SI, Coll P, Da Silva A et al (2002) Complex refractive index of Titan’s aerosol analogues in the 200–900 nm domain. Icarus 156:515–530CrossRefADSGoogle Scholar
  14. Ramirez SI, Coll P, Buch A, Brasse C, Poch O, Raulin F (2010) The fate of aerosols on the surface of Titan. Faraday Discuss 147:419–427CrossRefADSGoogle Scholar
  15. Raulin F, Brasse C, Poch O, Coll P (2012) Prebiotic-like chemistry on Titan. Chem Soc Rev 41(16):5380–5393CrossRefGoogle Scholar
  16. Sagan C, Khare BN (1979) Tholins: organic chemistry of interstellar grains and gas. Nature 277:102–107CrossRefADSGoogle Scholar
  17. Szopa C, Cernogora G, Boufendi L et al (2006) PAMPRE: a dusty plasma experiment for Titan’s tholins production and study. Planet Space Sci 54:394–404CrossRefADSGoogle Scholar
  18. Waite JH Jr, Young DT, Cravens TE et al (2007) The process of tholin formation in Titan’s upper atmosphere. Science 316:870–875CrossRefADSGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.LISA – UMR CNRS 7583, Faculté des Sciences et TechnologieUniversité Paris Est Créteil et Paris DiderotCreteilFrance