Advertisement

Solar Physics

, 294:165 | Cite as

Non-Equilibrium Spectrum Formation Affecting Solar Irradiance

  • Robert J. RuttenEmail author
Editor’s Choice
Part of the following topical collections:
  1. Irradiance Variations of the Sun and Sun-like Stars

Abstract

This is an overview of non-equilibrium aspects of the formation of solar continua and lines affecting the contributions by magnetic network and plage to spectrally resolved solar irradiance. After a brief summary of these contributions and a compact refresher of solar spectrum formation, the emphasis is on graphical exposition. Major obstacles for simulation-based irradiance studies are how to cope with NLTE scattering in the violet and ultraviolet line haze and how to cope with retarded hydrogen opacities in infrared and mm radiation.

Keywords

Spectrum Solar irradiance 

Notes

Acknowledgments

I thank the organizers of Focus Meeting FM9 at the 30th General Assembly of the IAU for inviting me to review this topic and so triggering this publication. I thank the reviewer for suggesting many improvements and ADS for assistance with its page serving.

Disclosure of Potential Conflicts of Interest

The author declares to have no conflicts of interest.

References

  1. Anderson, L.S.: 1989, Line blanketing without local thermodynamic equilibrium. II – A solar-type model in radiative equilibrium. Astrophys. J.339, 558. DOI. ADS. ADSCrossRefGoogle Scholar
  2. Asplund, M., Grevesse, N., Sauval, A.J., Scott, P.: 2009, The chemical composition of the Sun. Annu. Rev. Astron. Astrophys.47, 481. DOI. ADS. ADSCrossRefGoogle Scholar
  3. Avrett, E.H.: 1965, Solutions of the two-level line transfer problem with complete redistribution. SAO Spec. Rep.174, 101. ADS. ADSGoogle Scholar
  4. Avrett, E.H.: 1990, Models of the solar outer photosphere. In: Stenflo, J.O. (ed.) Solar Photosphere: Structure, Convection, and Magnetic Fields, IAU Symp.138, Kluwer, Dordrecht, 3. ADS. CrossRefGoogle Scholar
  5. Avrett, E.H., Loeser, R.: 2008, Models of the solar chromosphere and transition region from SUMER and HRTS observations: formation of the extreme-ultraviolet spectrum of hydrogen, carbon, and oxygen. Astron. Astrophys. Suppl. Ser.175, 229. DOI. ADS. ADSCrossRefGoogle Scholar
  6. Ayres, T.R.: 1989, How deep can one see into the Sun? Solar Phys.124, 15. DOI. ADS. ADSCrossRefGoogle Scholar
  7. Barbier, D.: 1943, Sur la théorie du spectre continu des étoiles. Ann. Astrophys.6, 113. ADS. ADSMathSciNetGoogle Scholar
  8. Berger, T.E., Rouppe van der Voort, L.H.M., Löfdahl, M.G., Carlsson, M., Fossum, A., Hansteen, V.H., Marthinussen, E., Title, A., Scharmer, G.: 2004, Solar magnetic elements at 0.1 arcsec resolution. General appearance and magnetic structure. Astron. Astrophys.428, 613. DOI. ADS. ADSCrossRefGoogle Scholar
  9. Bruls, J.H.M.J., Rutten, R.J., Shchukina, N.G.: 1992, The formation of helioseismology lines. I – NLTE effects in alkali spectra. Astron. Astrophys.265, 237. ADS. ADSGoogle Scholar
  10. Cannon, C.J.: 1973, Frequency-quadrature perturbations in radiative-transfer theory. Astrophys. J.185, 621. DOI. ADS. ADSCrossRefGoogle Scholar
  11. Carlsson, M.: 1986, A computer program for solving multi-level non-LTE radiative transfer problems in moving or static atmospheres. Uppsala Astron. Obs. Rep.33. ADS.
  12. Carlsson, M., Stein, R.F.: 1995, Does a nonmagnetic solar chromosphere exist? Astrophys. J. Lett.440, L29. DOI. ADS. ADSCrossRefGoogle Scholar
  13. Carlsson, M., Stein, R.F.: 2002, Dynamic hydrogen ionization. Astrophys. J.572, 626. DOI. ADS. ADSCrossRefGoogle Scholar
  14. Carlsson, M., Stein, R.F., Nordlund, Å., Scharmer, G.B.: 2004, Observational manifestations of solar magnetoconvection: center-to-limb variation. Astrophys. J. Lett.610, L137. DOI. ADS. ADSCrossRefGoogle Scholar
  15. Carlsson, M., Hansteen, V.H., Gudiksen, B.V., Leenaarts, J., De Pontieu, B.: 2016, A publicly available simulation of an enhanced network region of the Sun. Astron. Astrophys.585, A4. DOI. ADS. ADSCrossRefGoogle Scholar
  16. Chapman, G.A.: 1970, On the physical conditions in the photospheric network: an improved model of solar faculae. Solar Phys.14, 315. DOI. ADS. ADSCrossRefGoogle Scholar
  17. Eddington, A.S.: 1926, The Internal Constitution of the Stars, Cambridge University Press, Cambridge. ADS. zbMATHGoogle Scholar
  18. Eddington, A.S.: 1929, The formation of absorption lines. Mon. Not. Roy. Astron. Soc.89, 620. DOI. ADS. ADSCrossRefzbMATHGoogle Scholar
  19. Fontenla, J.M., Avrett, E.H., Loeser, R.: 1993, Energy balance in the solar transition region. III – helium emission in hydrostatic, constant-abundance models with diffusion. Astrophys. J.406, 319. DOI. ADS. ADSCrossRefGoogle Scholar
  20. Fontenla, J.M., Stancil, P.C., Landi, E.: 2015, Solar spectral irradiance, solar activity, and the near-ultra-violet. Astrophys. J.809, 157. DOI. ADS. ADSCrossRefGoogle Scholar
  21. Fontenla, J.M., Curdt, W., Haberreiter, M., Harder, J., Tian, H.: 2009, Semiempirical models of the solar atmosphere. III. Set of non-LTE models for far-ultraviolet/extreme-ultraviolet irradiance computation. Astrophys. J.707, 482. DOI. ADS. ADSCrossRefGoogle Scholar
  22. Frazier, E.N., Stenflo, J.O.: 1978, Magnetic, velocity and brightness structure of solar faculae. Astron. Astrophys.70, 789. ADS. ADSGoogle Scholar
  23. Gadun, A.S., Solanki, S.K., Sheminova, V.A., Ploner, S.R.O.: 2001, A formation mechanism of magnetic elements in regions of mixed polarity. Solar Phys.203, 1. DOI. ADS. ADSCrossRefGoogle Scholar
  24. Golding, T.P., Carlsson, M., Leenaarts, J.: 2014, Detailed and simplified nonequilibrium helium ionization in the solar atmosphere. Astrophys. J.784, 30. DOI. ADS. ADSCrossRefGoogle Scholar
  25. Greve, A., Zwaan, C.: 1980, Methods for the analysis of stellar spectra veiled by lines. Astron. Astrophys.90, 239. ADS. ADSGoogle Scholar
  26. Grossmann-Doerth, U., Schüssler, M., Steiner, O.: 1998, Convective intensification of solar surface magnetic fields: results of numerical experiments. Astron. Astrophys.337, 928. ADS. ADSGoogle Scholar
  27. Grossmann-Doerth, U., Knölker, M., Schüssler, M., Solanki, S.K.: 1994, The deep layers of solar magnetic elements. Astron. Astrophys.285, 648. ADS. ADSGoogle Scholar
  28. Holweger, H., Müller, E.A.: 1974, The photospheric barium spectrum – solar abundance and collision broadening of BA II lines by hydrogen. Solar Phys.39, 19. DOI. ADS. ADSCrossRefGoogle Scholar
  29. Houtgast, J.: 1942, The variations in the profiles of strong Fraunhofer lines along a radius of the solar disc. Ph.D. thesis, Utrecht University, June 1942, 154 pp. Supervisor: M. Minnaert. Drukkerij, F. Schotanus and Jens. ADS.
  30. Hubený, I.: 1987, Probabilistic interpretation of radiative transfer. I – The square root of epsilon law. II – Rybicki equation. Astron. Astrophys.185, 332. ADS. ADSMathSciNetGoogle Scholar
  31. Hubený, I., Mihalas, D.: 2014, Theory of Stellar Atmospheres, Princeton University Press, Princeton. ADS. zbMATHGoogle Scholar
  32. Ivanov, V.V.: 1973, Transfer of Radiation in Spectral Lines, NBS, Washington. ADS. CrossRefGoogle Scholar
  33. Jefferies, J.T.: 1968, Spectral Line Formation, Blaisdell, Waltham. ADS. Google Scholar
  34. Keller, C.U., Schüssler, M., Vögler, A., Zakharov, V.: 2004, On the origin of solar faculae. Astrophys. J. Lett.607, L59. DOI. ADS. ADSCrossRefGoogle Scholar
  35. Kourganoff, V.: 1952, Basic Methods in Transfer Problems; Radiative Equilibrium and Neutron Diffusion, Clarendon Press, Oxford. ADS. zbMATHGoogle Scholar
  36. Kurucz, R.: 1993, ATLAS9 Stellar Atmosphere Programs and 2 km/s grid. ATLAS9 Stellar Atmosphere Programs and 2 km/s grid. Kurucz CD-ROM No. 13. Smithsonian Astrophys. Obs., Cambridge, Mass., ADS.
  37. Kurucz, R.L.: 2009, Including all the lines. In: Hubený, I., Stone, J.M., MacGregor, K., Werner, K. (eds.) Am. Inst. Phys.CS-1171, Am. Inst. Phys., Melville, 43. DOI. ADS. CrossRefGoogle Scholar
  38. Kurucz, R.L.: 1970, Atlas: a computer program for calculating model stellar atmospheres. SAO Special Report309. ADS.
  39. Labs, D., Neckel, H.: 1972, Remarks on the convergency of photospheric model conceptions and the solar quasi continuum. Solar Phys.22, 64. DOI. ADS. ADSCrossRefGoogle Scholar
  40. Leenaarts, J.: 2018, Tracing the evolution of radiation-MHD simulations of solar and stellar atmospheres in the Lagrangian frame. Astron. Astrophys.616, A136. DOI. ADS. ADSCrossRefGoogle Scholar
  41. Leenaarts, J., Carlsson, M.: 2009, MULTI3D: a domain-decomposed 3D radiative transfer code. In: Lites, B., Cheung, M., Magara, T., Mariska, J., Reeves, K. (eds.) The Second Hinode Science Meeting: Beyond Discovery-Toward Understanding, CS-415, Astron. Soc. Pacific, San Francisco, 87. ADS. Google Scholar
  42. Leenaarts, J., Carlsson, M., Rouppe van der Voort, L.: 2012, The formation of the H\(\upalpha \) line in the solar chromosphere. Astrophys. J.749, 136. DOI. ADS. ADSCrossRefGoogle Scholar
  43. Leenaarts, J., Rutten, R.J., Carlsson, M., Uitenbroek, H.: 2006, A comparison of solar proxy-magnetometry diagnostics. Astron. Astrophys.452, L15. DOI. ADS. ADSCrossRefGoogle Scholar
  44. Leenaarts, J., Carlsson, M., Hansteen, V., Rutten, R.J.: 2007, Non-equilibrium hydrogen ionization in 2D simulations of the solar atmosphere. Astron. Astrophys.473, 625. DOI. ADS. ADSCrossRefGoogle Scholar
  45. Lockyer, J.N.: 1868, Spectroscopic observation of the Sun, No. II. Proc. Roy. Soc. London Ser. I17, 131. ADS. ADSGoogle Scholar
  46. Martínez-Sykora, J., De Pontieu, B., Carlsson, M., Hansteen, V.H., Nóbrega-Siverio, D., Gudiksen, B.V.: 2017, Two-dimensional radiative magnetohydrodynamic simulations of partial ionization in the chromosphere. II. Dynamics and energetics of the low solar atmosphere. Astrophys. J.847, 36. DOI. ADS. ADSCrossRefGoogle Scholar
  47. Menzel, D.H., Cillié, G.G.: 1937, Hydrogen emission in the chromosphere. Astrophys. J.85, 88. DOI. ADS. ADSCrossRefGoogle Scholar
  48. Mihalas, D.: 1970, Stellar Atmospheres, Freeman, San Francisco. ADS. Google Scholar
  49. Mihalas, D.: 1978, Stellar Atmospheres, 2nd edn., Freeman, San Francisco. ADS. Google Scholar
  50. Milne, E.A.: 1921, Radiative equilibrium in the outer layers of a star. Mon. Not. Roy. Astron. Soc.81, 361. DOI. ADS. ADSCrossRefGoogle Scholar
  51. Neckel, H.: 1999, Announcement. Solar Phys.184, 421. DOI. ADS. ADSCrossRefGoogle Scholar
  52. Neckel, H., Labs, D.: 1984, The solar radiation between 3300 and 12500 Å. Solar Phys.90, 205. DOI. ADS. ADSCrossRefGoogle Scholar
  53. Nóbrega-Siverio, D., Moreno-Insertis, F., Martínez-Sykora, J.: 2018, On the importance of the nonequilibrium ionization of Si IV and O IV and the line of sight in solar surges. Astrophys. J.858, 8. DOI. ADS. ADSCrossRefGoogle Scholar
  54. Norris, C.M., Beeck, B., Unruh, Y.C., Solanki, S.K., Krivova, N.A., Yeo, K.L.: 2017, Spectral variability of photospheric radiation due to faculae. I. The Sun and sun-like stars. Astron. Astrophys.605, A45. DOI. ADS. ADSCrossRefGoogle Scholar
  55. Paletou, F.: 2018, On Milne–Barbier–Unsöld relationships. Open Astron. J.27, 76. DOI. ADS. ADSCrossRefGoogle Scholar
  56. Pereira, T.M.D.: 2019, The dynamic chromosphere: pushing the boundaries of observations and models. Adv. Space Res.63, 1434. DOI. ADS. ADSCrossRefGoogle Scholar
  57. Pereira, T.M.D., Uitenbroek, H.: 2015, RH 1.5D: a massively parallel code for multi-level radiative transfer with partial frequency redistribution and Zeeman polarisation. Astron. Astrophys.574, A3. DOI. ADS. ADSCrossRefGoogle Scholar
  58. Rouppe van der Voort, L., Leenaarts, J., De Pontieu, B., Carlsson, M., Vissers, G.: 2009, On-disk counterparts of type II spicules in the Ca II 854.2 nm and H\(\upalpha \) lines. Astrophys. J.705, 272. DOI. ADS. ADSCrossRefGoogle Scholar
  59. Rutten, R.J.: 1988, The NLTE formation of iron lines in the solar photosphere. In: Viotti, R., Vittone, A., Friedjung, M. (eds.) IAU Colloq. 94: Physics of Formation of Fe II Lines Outside LTE, Astrophys. Space Sci. Lib.138, 185. DOI. ADS. CrossRefGoogle Scholar
  60. Rutten, R.J.: 1999, (Inter-),network structure and dynamics. In: Schmieder, B., Hofmann, A., Staude, J. (eds.) Third Advances in Solar Physics Euroconference: Magnetic Fields and OscillationsCS-184, Astron. Soc. Pacific, San Francisco, 181. ADS. Google Scholar
  61. Rutten, R.J.: 2003a, Epsilon. In: Andreasian, N. (ed.) Richard Nelson Thomas: NonEquilibrium Thermodynamical Astrophysicist, University of Colorado, Boulder, 78. Google Scholar
  62. Rutten, R.J.: 2003b, Radiative Transfer in Stellar Atmospheres. ADS. Google Scholar
  63. Rutten, R.J.: 2016, H\(\upalpha \) features with hot onsets. I. Ellerman bombs. Astron. Astrophys.590, A124. DOI. ADS. ADSCrossRefGoogle Scholar
  64. Rutten, R.J.: 2017a, Solar ALMA predictions: tutorial. In: Vargas Domínguez, S., Kosovichev, A.G., Antolin, P., Harra, L. (eds.) IAU Symp.327, Cambridge Univ. Press, Cambridge, 1. DOI. CrossRefGoogle Scholar
  65. Rutten, R.J.: 2017b, Solar H-alpha features with hot onsets. III. Long fibrils in Lyman-alpha and with ALMA. Astron. Astrophys.598, A89. DOI. ADS. ADSCrossRefGoogle Scholar
  66. Rutten, R.J., Rouppe van der Voort, L.H.M.: 2017, Solar H\(\upalpha \) features with hot onsets. II. A contrail fibril. Astron. Astrophys.597, A138. DOI. ADS. ADSCrossRefGoogle Scholar
  67. Rutten, R.J., Uitenbroek, H.: 2012, Chromospheric backradiation in ultraviolet continua and H\(\upalpha \). Astron. Astrophys.540, A86. DOI. ADS. ADSCrossRefGoogle Scholar
  68. Rybicki, G.B., Hummer, D.G.: 1992, An accelerated lambda iteration method for multilevel radiative transfer. II – Overlapping transitions with full continuum. Astron. Astrophys.262, 209. ADS. ADSGoogle Scholar
  69. Rybicki, G.B., Lightman, A.P.: 1986, Radiative Processes in Astrophysics, Wiley, New York, 400. ADS. Google Scholar
  70. Sekse, D.H., Rouppe van der Voort, L., De Pontieu, B., Scullion, E.: 2013, Interplay of three kinds of motion in the disk counterpart of type II spicules: upflow, transversal, and torsional motions. Astrophys. J.769, 44. DOI. ADS. ADSCrossRefGoogle Scholar
  71. Sheminova, V.A., Rutten, R.J., Rouppe van der Voort, L.H.M.: 2005, The wings of Ca II H and K as solar fluxtube diagnostics. Astron. Astrophys.437, 1069. DOI. ADS. ADSCrossRefGoogle Scholar
  72. Short, C.I., Hauschildt, P.H.: 2005, A non-LTE line-blanketed model of a solar-type star. Astrophys. J.618, 926. DOI. ADS. ADSCrossRefGoogle Scholar
  73. Solanki, S.K.: 1993, Smallscale solar magnetic fields – an overview. Space Sci. Rev.63, 1. DOI. ADS. ADSCrossRefGoogle Scholar
  74. Spruit, H.C.: 1976, Pressure equilibrium and energy balance of small photospheric fluxtubes. Solar Phys.50, 269. DOI. ADS. ADSCrossRefGoogle Scholar
  75. Steiner, O.: 2005, Radiative properties of magnetic elements. II. Center to limb variation of the appearance of photospheric faculae. Astron. Astrophys.430, 691. DOI. ADS. ADSCrossRefGoogle Scholar
  76. Steiner, O., Grossmann-Doerth, U., Knölker, M., Schüssler, M.: 1998, Dynamical interaction of solar magnetic elements and granular convection: results of a numerical simulation. Astrophys. J.495, 468. DOI. ADS. ADSCrossRefGoogle Scholar
  77. Stenflo, J.O.: 1973, Magnetic-field structure of the photospheric network. Solar Phys.32, 41. DOI. ADS. ADSCrossRefGoogle Scholar
  78. Stenflo, J.O.: 1975, A model of the supergranulation network and of active-region plages. Solar Phys.42, 79. DOI. ADS. ADSCrossRefGoogle Scholar
  79. Sukhorukov, A.V., Leenaarts, J.: 2017, Partial redistribution in 3D non-LTE radiative transfer in solar-atmosphere models. Astron. Astrophys.597, A46. DOI. ADS. ADSCrossRefGoogle Scholar
  80. Thomas, R.N.: 1957, The source function in a non-equilibrium atmosphere. I. The resonance lines. Astrophys. J.125, 260. DOI. ADS. ADSCrossRefGoogle Scholar
  81. Title, A.M., Berger, T.E.: 1996, Double-Gaussian models of bright points or why bright points are usually dark. Astrophys. J.463, 797. DOI. ADS. ADSCrossRefGoogle Scholar
  82. Uitenbroek, H.: 2001, Multilevel radiative transfer with partial frequency redistribution. Astrophys. J.557, 389. DOI. ADS. ADSCrossRefGoogle Scholar
  83. Uitenbroek, H., Bruls, J.H.M.J.: 1992, The formation of helioseismology lines. III – Partial redistribution effects in weak solar resonance lines. Astron. Astrophys.265, 268. ADS. ADSGoogle Scholar
  84. Uitenbroek, H., Criscuoli, S.: 2011, Why one-dimensional models fail in the diagnosis of average spectra from inhomogeneous stellar atmospheres. Astrophys. J.736, 69. DOI. ADS. ADSCrossRefGoogle Scholar
  85. Unruh, Y.C., Solanki, S.K., Fligge, M.: 1999, The spectral dependence of facular contrast and solar irradiance variations. Astron. Astrophys.345, 635. ADS. ADSGoogle Scholar
  86. Vernazza, J.E., Avrett, E.H., Loeser, R.: 1981, Structure of the solar chromosphere. III – Models of the EUV brightness components of the quiet-sun. Astron. Astrophys. Suppl. Ser.45, 635. DOI. ADS. ADSCrossRefGoogle Scholar
  87. Vitas, N., Viticchiè, B., Rutten, R.J., Vögler, A.: 2009, Explanation of the activity sensitivity of Mn I 5394.7 Å. Astron. Astrophys.499, 301. DOI. ADS. ADSCrossRefGoogle Scholar
  88. Vögler, A., Shelyag, S., Schüssler, M., Cattaneo, F., Emonet, T., Linde, T.: 2005, Simulations of magneto-convection in the solar photosphere. Equations, methods, and results of the MURaM code. Astron. Astrophys.429, 335. DOI. ADS. ADSCrossRefGoogle Scholar
  89. Werner, K., Deetjen, J.L., Dreizler, S., Nagel, T., Rauch, T., Schuh, S.L.: 2003, Model photospheres with accelerated lambda iteration. In: Hubený, I., Mihalas, D., Werner, K. (eds.) Stellar Atmosphere ModelingCS-288, Astron. Soc. Pacific, San Francisco, 31. ADS. Google Scholar
  90. Wijbenga, J.W., Zwaan, C.: 1972, Empirical NLTE analyses of solar spectral lines. I: a method and some applications to earlier analyses. Solar Phys.23, 265. DOI. ADS. ADSCrossRefGoogle Scholar
  91. Yelles Chaouche, L., Solanki, S.K., Schüssler, M.: 2009, Comparison of the thin flux tube approximation with 3D MHD simulations. Astron. Astrophys.504, 595. DOI. ADS. ADSCrossRefzbMATHGoogle Scholar
  92. Zwaan, C.: 1967, Small-scale solar magnetic fields and ‘invisible sunspots’. Solar Phys.1, 478. DOI. ADS. ADSCrossRefGoogle Scholar

Copyright information

© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.Lingezicht AstrophysicsDeilThe Netherlands
  2. 2.Institute of Theoretical AstrophysicsUniversity of OsloOsloNorway
  3. 3.Rosseland Centre for Solar PhysicsUniversity of OsloOsloNorway

Personalised recommendations