NLTE Radiative Transfer in Cool Stars

Theory and Applications to the Abundance Analysis for 24 Chemical Elements
  • Maria Bergemann
  • Thomas Nordlander
Part of the GeoPlanet: Earth and Planetary Sciences book series (GEPS)


The interpretation of observed spectra of stars in terms of fundamental stellar properties is a key problem in astrophysics. For FGK-type stars, the radiative transfer models are often computed using the assumption of local thermodynamic equilibrium (LTE). Its validity is often questionable and needs to be supported by detailed studies, which build upon the consistent framework of NLTE. In this review, we outline the theory of NLTE. The processes causing departures from LTE are introduced qualitatively by their physical interpretation, as well as quantitatively by their impact on the models of stellar spectra and element abundances. We also compile and analyse the most recent results from the literature. In particular, we examine the NLTE effects for 24 chemical elements for six well-studied FGK-type stars.


Line: formation Radiation mechanisms: general Radiative transfer Stars: atmospheres Stars: late-type 



Figure 3 has been kindly provided by Rob Rutten;


  1. Asplund M (2005) Ann Rev A&A 43:481CrossRefGoogle Scholar
  2. Baumueller D, Gehren T (1997) A&A 325:1088Google Scholar
  3. Bergemann M (2011) MNRAS 413:2184CrossRefGoogle Scholar
  4. Bergemann M, Cescutti G (2010) A&A 522:A9CrossRefGoogle Scholar
  5. Bergemann M, Gehren T (2008) A&A 492:823CrossRefGoogle Scholar
  6. Bergemann M, Pickering JC, Gehren T (2010) MNRAS 401:1334CrossRefGoogle Scholar
  7. Bergemann M, Hansen CJ, Bautista M, Ruchti G (2012a) A&A 546:A90CrossRefGoogle Scholar
  8. Bergemann M, Lind K, Collet R, Magic Z, Asplund M (2012b) MNRAS 427:27CrossRefGoogle Scholar
  9. Bergemann M, Kudritzki RP, Würl M, Plez B, Davies B, Gazak Z (2013) ApJ 764:115CrossRefGoogle Scholar
  10. Bruls JHMJ, Rutten RJ, Shchukina NG (1992) A&A 265:237Google Scholar
  11. Caffau E, Maiorca E, Bonifacio P, Faraggiana R, Steffen M, Ludwig HG, Kamp I, Busso M (2009) A&A 498:877CrossRefGoogle Scholar
  12. Fabbian D, Asplund M, Carlsson M, Kiselman D (2006) A&A 458:899CrossRefGoogle Scholar
  13. Gehren T, Butler K, Mashonkina L, Reetz J, Shi J (2001) A&A 366:981CrossRefGoogle Scholar
  14. Gehren T, Shi JR, Zhang HW, Zhao G, Korn AJ (2006) A&A 451:1065CrossRefGoogle Scholar
  15. Johnson HR, Milkey RW, Ramsey LW (1974) ApJ 187:147CrossRefGoogle Scholar
  16. Kiselman D, Carlsson M (1996) A&A 311:680Google Scholar
  17. Kunc JA, Soon WH (1991) J Chem Phys 95:5738CrossRefGoogle Scholar
  18. Lind K, Asplund M, Barklem PS (2009) A&A 503:541CrossRefGoogle Scholar
  19. Lind K, Asplund M, Barklem PS, Belyaev AK (2011) A&A 528:A103CrossRefGoogle Scholar
  20. Lind K, Bergemann M, Asplund M (2012) MNRAS 427:50CrossRefGoogle Scholar
  21. Lind K, Melendez J, Asplund M, Collet R, Magic Z (2013) A&A 554:A96CrossRefGoogle Scholar
  22. Mashonkina L, Gehren T, Bikmaev I (1999) A&A 343:519Google Scholar
  23. Mashonkina L, Korn AJ, Przybilla N (2007) A&A 461:261CrossRefGoogle Scholar
  24. Mashonkina L, Zhao G, Gehren T, Aoki W, Bergemann M, Noguchi K, Shi JR, Takada-Hidai M, Zhang HW (2008) A&A 478:529CrossRefGoogle Scholar
  25. Mashonkina L, Ryabtsev A, Frebel A (2012) A&A 540:A98CrossRefGoogle Scholar
  26. Mihalas D (1978) Stellar atmospheres, 2nd edn. W. H. Freeman and Co, San FranciscoGoogle Scholar
  27. Mihalas D, Athay RG (1973) Ann Rev A&A 11:187CrossRefGoogle Scholar
  28. Reetz JK (1998) Sauerstoff in kühlen Sternen und die chemische Entwicklung der GalaxisGoogle Scholar
  29. Rybicki GB, Hummer DG (1992) A&A 262:209Google Scholar
  30. Sitnova TM, Mashonkina LI, Ryabchikova TA (2013) Astron Lett 39:126CrossRefGoogle Scholar
  31. Takeda Y, Zhao G, Chen YQ, Qiu HM, Takada-Hidai M (2002) PASJ 54:275Google Scholar
  32. Takeda Y, Hashimoto O, Taguchi H, Yoshioka K, Takada-Hidai M, Saito Y, Honda S (2005) PASJ 57:751Google Scholar
  33. Wijbenga JW, Zwaan C (1972) Solar Phys 23:265CrossRefGoogle Scholar
  34. Würl M (2012) NLTE analysis of silicon lines in solar-type stars and red super-giantsGoogle Scholar
  35. Zhang HW, Gehren T, Zhao G (2008) A&A 481:489CrossRefGoogle Scholar
  36. Zhao G, Butler K, Gehren T (1998) A&A 333:219Google Scholar

Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  1. 1.Institute of AstronomyUniversity of CambridgeCambridgeUK
  2. 2.Division of Astronomy and Space Physics, Department of Physics and AstronomyUppsala UniversityUppsalaSweden

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