Hostname: page-component-7479d7b7d-qlrfm Total loading time: 0 Render date: 2024-07-12T11:26:05.628Z Has data issue: false hasContentIssue false
  • English
  • Français

A Magnetic Field Strength vs. Temperature Relation in Sunspots

Published online by Cambridge University Press:  03 August 2017

Greg Kopp  and
Douglas Rabin
Greg Kopp
Affiliation:
National Solar Observatory, National Optical Astronomy Observatories,* P.O. Box 26732, Tucson, AZ 85726, U.S.A.
Douglas Rabin
Affiliation:
National Solar Observatory, National Optical Astronomy Observatories,* P.O. Box 26732, Tucson, AZ 85726, U.S.A.

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The near infrared presents several new and powerful advantages in the diagnostics of sunspot atmospheres: (1) increased magnetic sensitivity in Zeeman-split lines, (2) increased sensitivity of umbral brightness to temperature, and (3) reduced scattered light and seeing disturbances due to atmospheric turbulence. This has revealed a strong and consistent relationship between sunspot brightness and magnetic field strength.

We have made spatial/spectral observations of sunspots in the highly sensitive (g = 3) Fe I line at λ = 1.5649 μm to compare field strengths with continuum intensities. We find a characteristic but nonlinear relationship between magnetic field strength, B, and brightness temperature, Tb, in sunspots. In umbrae there is an approximately linear relation between B2 and Tb.

Keywords

infrared: starsSun: magnetic fieldssunspots
Type
Part 5: Magnetic Fields and Infrared Magnetometry
Information
Symposium - International Astronomical Union , Volume 154: Infrared Solar Physics , 1994 , pp. 477 - 482
Copyright
Copyright © Kluwer 1994 

References

Adam, M. G.: 1990, Solar Phys. 125, 37.Google Scholar
Beckers, J. M., and Schröter, E. H.: 1969, Solar Phys. 10, 384.Google Scholar
del Toro Iniesta, J.C., Martinez Pillet, V., and Vasquez, M.: 1991, in November, L. (ed.), Solar Polarimetry (Proc. 11th Sacramento Peak Workshop), Sunspot, New Mexico, p. 224.Google Scholar
Fowler, A. M., Probst, R. G., Britt, J. P., Joyce, R. R., and Gillett, F. C.: 1987, Opt. Eng. 26, 232.CrossRefGoogle Scholar
Gurman, J., and House, L.: 1981, Solar Phys. 71, 5.CrossRefGoogle Scholar
Harvey, J. W., and Hall, D.: 1975, Bull. Amer. Astron. Soc. 7, 459.Google Scholar
Kopp, G., and Rabin, D.: 1992, Solar Phys. 141, 253.CrossRefGoogle Scholar
McPherson, M. R., Lin, H., and Kuhn, J. R.: 1992, Solar Phys. 139, 255.CrossRefGoogle Scholar
Pierce, K.: 1991, Solar Phys. 133, 215.Google Scholar
Rabin, D.: 1992, Astrophys. J. 391, 832.Google Scholar
Solanki, S. K., Biémont, E., and Mürset, U.: 1990, Astron. Astrophys. Suppl. 83, 307.Google Scholar
Stenflo, J. O., Solanki, S. K., and Harvey, J. W.: 1987, Astron. Astrophys. 173, 167.Google Scholar
Wallace, L., and Livingston, W.: 1992, An Atlas of a Dark Sunspot Umbral Spectrum from 1970 to 8640 cm–1 (1.16 to 5.1 μm), Kitt Peak National Observatory, Tucson.Google Scholar