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Title: MODELING THE CHROMOSPHERE OF A SUNSPOT AND THE QUIET SUN

Abstract

Semiempirical atmospheric modeling attempts to match an observed spectrum by finding the temperature distribution and other physical parameters along the line of sight through the emitting region such that the calculated spectrum agrees with the observed one. In this paper we take the observed spectrum of a sunspot and the quiet Sun in the EUV wavelength range 668–1475 Å from the 2001 SUMER atlas of Curdt et al. to determine models of the two atmospheric regions, extending from the photosphere through the overlying chromosphere into the transition region. We solve the coupled statistical equilibrium and optically thick radiative transfer equations for a set of 32 atoms and ions. The atoms that are part of molecules are treated separately, and are excluded from the atomic abundances and atomic opacities. We compare the Mg ii k line profile observations from the Interface Region Imaging Spectrograph with the profiles calculated from the two models. The calculated profiles for the sunspot are substantially lower than the observed ones, based on the SUMER models. The only way we have found to raise the calculated Mg ii lines to agree with the observations is to introduce illumination of the sunspot from the surrounding active region.

Authors:
;  [1];  [2];  [3];  [4]
  1. Smithsonian Astrophysical Observatory, Cambridge, MA 02138 (United States)
  2. Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109 (United States)
  3. Max Planck Institut für Sonnensystemfoschung, Goettingen (Germany)
  4. Lockheed Martin Advanced Techonology Center (United States)
Publication Date:
OSTI Identifier:
22524893
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 811; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ATOMS; CHROMOSPHERE; COMPARATIVE EVALUATIONS; EQUILIBRIUM; EXTREME ULTRAVIOLET RADIATION; ILLUMINANCE; MAGNESIUM IONS; MOLECULES; OPACITY; PHOTOSPHERE; RADIANT HEAT TRANSFER; SUN; SUNSPOTS; TEMPERATURE DISTRIBUTION

Citation Formats

Avrett, E., Tian, H., Landi, E., Curdt, W., and Wülser, J.-P. MODELING THE CHROMOSPHERE OF A SUNSPOT AND THE QUIET SUN. United States: N. p., 2015. Web. doi:10.1088/0004-637X/811/2/87.
Avrett, E., Tian, H., Landi, E., Curdt, W., & Wülser, J.-P. MODELING THE CHROMOSPHERE OF A SUNSPOT AND THE QUIET SUN. United States. doi:10.1088/0004-637X/811/2/87.
Avrett, E., Tian, H., Landi, E., Curdt, W., and Wülser, J.-P. Thu . "MODELING THE CHROMOSPHERE OF A SUNSPOT AND THE QUIET SUN". United States. doi:10.1088/0004-637X/811/2/87.
@article{osti_22524893,
title = {MODELING THE CHROMOSPHERE OF A SUNSPOT AND THE QUIET SUN},
author = {Avrett, E. and Tian, H. and Landi, E. and Curdt, W. and Wülser, J.-P.},
abstractNote = {Semiempirical atmospheric modeling attempts to match an observed spectrum by finding the temperature distribution and other physical parameters along the line of sight through the emitting region such that the calculated spectrum agrees with the observed one. In this paper we take the observed spectrum of a sunspot and the quiet Sun in the EUV wavelength range 668–1475 Å from the 2001 SUMER atlas of Curdt et al. to determine models of the two atmospheric regions, extending from the photosphere through the overlying chromosphere into the transition region. We solve the coupled statistical equilibrium and optically thick radiative transfer equations for a set of 32 atoms and ions. The atoms that are part of molecules are treated separately, and are excluded from the atomic abundances and atomic opacities. We compare the Mg ii k line profile observations from the Interface Region Imaging Spectrograph with the profiles calculated from the two models. The calculated profiles for the sunspot are substantially lower than the observed ones, based on the SUMER models. The only way we have found to raise the calculated Mg ii lines to agree with the observations is to introduce illumination of the sunspot from the surrounding active region.},
doi = {10.1088/0004-637X/811/2/87},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 811,
place = {United States},
year = {2015},
month = {10}
}