Solar Physics

, Volume 213, Issue 1, pp 55–67 | Cite as

Temperature Dependence of Molecular Line Strengths and Fe i 1565 nm Zeeman Splitting in a Sunspot

  • M.J. Penn
  • S. Walton
  • G. Chapman
  • J. Ceja
  • W. Plick


Spectroscopic observations at 1565 nm were made in the eastern half of the main umbra of NOAA 9885 on 1 April 2002 using the National Solar Observatory McMath-Pierce Telescope at Kitt Peak with a tip-tilt image stabilization system and the California State University Northridge–National Solar Observatory infrared camera. The line depth of the OH blend at 1565.1 nm varies with the observed continuum temperature; the variation fits previous observations except that the continuum temperature is lower by 600 K. The equivalent width of the OH absorption line at 1565.2 nm shows a temperature dependence similar to previously published umbral molecular observations at 640 nm. A simple model of expected OH abundance based upon an ionization analogy to molecular dissociation is produced and agrees well with the temperature variation of the line equivalent width. A CN absorption line at 1564.6 nm shows a very different temperature dependence, likely due to complicated formation and destruction processes. Nonetheless a numerical fit of the temperature variation of the CN equivalent width is presented. Finally a comparison of the Zeeman splitting of the Fe i 1564.8 nm line with the sunspot temperature derived from the continuum intensity shows an umbra somewhat cooler for a given magnetic field strength than previous comparisons using this infrared 1564.8 nm line, but consistent with these previous infrared measurements the umbra is hotter for a given magnetic field strength than magnetic and temperature measurements at 630.2 nm would suggest. Differences between the 630.2 nm and 1564.8 nm umbral temperature and magnetic field relations are explained with the different heights of formation of the lines and continua at these wavelengths.


Absorption Line Magnetic Field Strength Equivalent Width Line Strength Zeeman Splitting 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Berdyugina, S. V. and Solanki, S. K.: 2002, Astron. Astrophys. 385, 701.Google Scholar
  2. Bhatnagar, A., Livingston, W. C., and Harvey, J. W.: 1972, Solar Phys. 27, 80.Google Scholar
  3. Boyer, R., Sotirovski, P., and Harvey, J. W.: 1982, Astron. Astrophys. Suppl. Ser. 47, 145.Google Scholar
  4. Bruls, J. H. M. J., Lites, B.W., and Murphy, G. A.: 1991, in L. J. November (ed.), Solar Polarimetry, Proceedings of the Eleventh NSO/Sac Peak Workshop, NSO, Sunspot, p. 444.Google Scholar
  5. Collados, M., Martinez Pillet, V., Ruiz Cobo, B., del Toro Iniesta, J. C., and Vazquez, M.: 1994, Astron. Astrophys. 291, 622.Google Scholar
  6. Costes, M., Naulin, C., and Dorthe, G.: 1990, Astron. Astrophys. 232, 270.Google Scholar
  7. Federman, S. R., Strom, C. J., Lambert, D. L., Cardelli, J. A., Smith, V. V., and Joseph, C. L.: 1994, Astrophys. J. 424, 772.Google Scholar
  8. Goldsmith, P. F. and Langer, W. D.: 1999, Astrophys. J. 517, 209.Google Scholar
  9. Gurman, J. B. and House, L. L.: 1981, Solar Phys. 71, 5.Google Scholar
  10. Harvey, J. W.: 1973, Solar Phys. 28, 43.Google Scholar
  11. Hollenbach, D. and McKee, C. F.: 1979, Astrophys. J. Suppl. Ser. 41, 555.Google Scholar
  12. Jones, H. P.: 1999, Bull. Am. Astron. Soc. 31, 958.Google Scholar
  13. Kollatschny, W., Stellmacher, G., Wiehr, E., and Falipou, M. A.: 1980, Astron. Astrophys. 86, 245.Google Scholar
  14. Kopp, G. and Rabin, D.: 1992, Solar Phys. 141, 253.Google Scholar
  15. Lambert, D. L.: 1968, Monthly Notices Royal Astron. Soc. 138, 143.Google Scholar
  16. Lin, H.: 2002, Bull. Am. Astron. Soc. 34, 690.Google Scholar
  17. Lites, B. W., Elmore, D. F., Seagraves, P., and Skumanich, A. P.: 1993, Astrophys. J. 418, 928.Google Scholar
  18. Livingston, W.: 2002, Solar Phys. 207, 41.Google Scholar
  19. Martinez Pillet, V. and Vazquez, M.: 1993, Astron. Astrophys. 270, 494.Google Scholar
  20. Mihalas, D.: 1978, Stellar Atmospheres, W. H. Freeman, New York.Google Scholar
  21. Moran, T., Deming, D., Jennings, D. E., and McCabe, G.: 2000, Astrophys. J. 533, 1035.Google Scholar
  22. Pahlke, K. D. and Wiehr, E.: 1990, Astron. Astrophys. 228, 246.Google Scholar
  23. Pierce, A. K.: 1964, Appl. Optics 3, 1337.Google Scholar
  24. Penn, M. J. and LaBonte, B. J.: 1993, Astrophys. J. 415, 383.Google Scholar
  25. Penn, M. J., Ceja, J. A., Bell, E., Frye, G., and Linck, R.: 2002, Solar Phys. 205, 53.Google Scholar
  26. Rabin, D., Clark, T. A., and Bergman, M. W.: 2000, Bull. Am. Astron. Soc. 32, 804.Google Scholar
  27. Rüedi, I., Solanki, S. K., and Livingston, W.: 1995, Astron. Astrophys. 302, 543.Google Scholar
  28. Sanchez Almeida, J., Asensio Ramos, A., Trujillo Bueno, J., and Cernicharo, J.: 2001, Astrophys. J. 555, 978.Google Scholar
  29. Solanki, S. K., Walther, U., and Livingston, W.: 1993, Astron. Astrophys. 277, 639.Google Scholar
  30. Stanchfield II, D. C. H., Thomas, J. H., and Lites, B. W.: 1997, Astrophys. J. 477, 485.Google Scholar
  31. Van Dishoeck, E. F. and Dalgarno, A.: 1984, Icarus 59, 305.Google Scholar
  32. Vernazza, J. E., Avrett, E. H., and Loeser, R.: 1976, Astrophys. J. Suppl. Ser. 30, 1.Google Scholar
  33. Wallace, L., Hinkle, K., and Livingston, W.: 2001, Sunspot Umbral Spectra in the Region 4000 to 8640 cm ?1 (1.16 to 2.50 µm), N.S.O. Technical Report #01-001, Tucson, AZ.Google Scholar

Copyright information

© Kluwer Academic Publishers 2003

Authors and Affiliations

  • M.J. Penn
    • 1
    • 2
  • S. Walton
    • 2
  • G. Chapman
    • 2
  • J. Ceja
    • 2
  • W. Plick
    • 3
  1. 1.National Solar ObservatoryTucson
  2. 2.Department of Physics and AstronomySan Fernando Observatory and California State University NorthridgeNorthridgeU.S.A
  3. 3.Department of Physics and AstronomyConnecticut CollegeNew LondonU.S.A

Personalised recommendations