Semiempirical Models of the Solar Atmosphere. I. The Quiet- and Active Sun Photosphere at Moderate Resolution

Inthispaperwestudyandmodifyprevioussemiempiricalmodelsofthesolarphotosphereasobservedatmoderate spatial and temporal resolution (� 3 00 and � 30 minutes, respectively) in the main quiet- and active Sun component features. Our present models are constructed to match the relevant available observations at this resolution for which a one-dimensional and time-independent stratification is reasonable. The models do not describe the fine structure and temporal variability observed in high-resolution images but correspond to a ‘‘radiation averaging’’ over the finestructure andp-modevariations. Weuse theobservedlimbdarkeningin therange0.3‐2.4 � m,as wellasthe absolute intensities and details of the spectral continua and lines in this range, to validate and adjust the models. Using the methoddescribedinapreviouspaper,wecomputetheemergentradiationfromourmodelsinfulldetailforthevisible and IR continuum and the lines in the interval 0.3‐5 � mf or which we have atomic data from NIST (� 13,000 lines used) and molecular data from HITRAN and Gray & Corbally (� 480,000 molecular lines used). The observations, abundances, and atomic/molecular data are improved over previous work and yield models that better fit the observations. In addition, we construct a new penumbra model. The visible and IR detailed spectra computed from these models provide insight for understanding the effects of magnetic fields on the solar irradiance and are useful tools for computing synthetic spectral irradiances in different solar activity configurations.

[1]  C. J. Wolfson,et al.  Time Variability of the “Quiet” Sun Observed with TRACE. I. Instrumental Effects, Event Detection, and Discrimination of Extreme-Ultraviolet Microflares , 2000 .

[2]  P. Maltby,et al.  A model for the penumbra of sunspots , 1969 .

[3]  J. Meléndez.  A Low Solar Oxygen Abundance from the First-Overtone OH Lines , 2004, astro-ph/0407366.

[4]  D. Kiselman,et al.  Line formation in solar granulation IV. (O I), O I and OH lines and the photospheric O abundance , 2003, astro-ph/0312290.

[5]  G. Thuillier,et al.  Calibration of the SOLSPEC Spectrometer to Measure the Solar Irradiance from Space , 1998 .

[6]  H. Dodson.  Intensity Measures of Calcium Plages for Comparison with 10.3-CENTIMETER Solar Radiation, October 16, 1951. , 1954 .

[7]  P. Mein,et al.  High resolution solar magnetometry with the spectrograph of the Pic du Midi Turret Dome , 2004 .

[8]  Philippe Lemaire,et al.  The SUMER spectral atlas of solar-disk features , 2001 .

[9]  J. C. D. T. Iniesta,et al.  On the temperature and velocity through the photosphere of a sunspot penumbra , 1994 .

[10]  A Reappraisal of the Solar Photospheric C/O Ratio , 2002, astro-ph/0206089.

[11]  Gary J. Rottman,et al.  The Spectral Irradiance Monitor: Scientific Requirements, Instrument Design, and Operation Modes , 2005 .

[12]  Christopher J. Corbally,et al.  The calibration of MK spectral classes using spectral synthesis. 1: The effective temperature calibration of dwarf stars , 1994 .

[13]  E. Avrett,et al.  Energy balance in the solar transition region. I - Hydrostatic thermal models with ambipolar diffusion , 1990 .

[14]  R. Kurucz,et al.  A new sunspot umbral model and its variation with the solar cycle , 1986 .

[15]  Mats G. Lofdahl,et al.  Solar magnetic elements at 0".1 resolution. General appearance and magnetic structure , 2004 .

[16]  H. Balthasar,et al.  Some properties of an isolated sunspot , 2005 .

[17]  S. Saar,et al.  Relations between the photospheric magnetic field and the emission from the outer atmospheres of cool stars. I - The solar CA II K line core emission , 1989 .

[18]  O. Gingerich,et al.  The Bilderberg model of the photosphere and low chromosphere , 1968 .

[19]  Juan M. Fontenla,et al.  Energy balance in the solar transition region. III - Helium emission in hydrostatic, constant-abundance models with diffusion , 1993 .

[20]  D. Weinberger,et al.  Solar limb darkening in the interval 7404-24 018 Å, II , 1977 .

[21]  O. Manuel.  Origin of elements in the solar system : implications of post-1957 observations , 2000 .

[22]  Juan M. Fontenla,et al.  The Lyman-Alpha Line in Various Solar Features. I. Observations , 1988 .

[23]  Eugene H. Avrett,et al.  Calculation of Solar Irradiances. I. Synthesis of the Solar Spectrum , 1999 .

[24]  P. Hauschildt,et al.  The Molecular Continuum Opacity of 24MgH in Cool Stellar Atmospheres , 2002, astro-ph/0207042.

[25]  A. Cox,et al.  Allen's astrophysical quantities , 2000 .

[26]  Owen Gingerich,et al.  The Harvard-Smithsonian reference atmosphere , 1971 .

[27]  J. Bonet,et al.  Infrared Photometry of Solar Photospheric Structures. II. Center-to-Limb Variation of Active Regions , 2002 .

[28]  Robert L. Kurucz,et al.  Model Atmospheres for Population Synthesis , 1992 .

[29]  W. Kalkofen.  The Case against Cold, Dark Chromospheres , 2001, astro-ph/0106072.

[30]  M. Bautista,et al.  Implementing TOPbase/Iron Project: Continuous Absorption from Fe ii , 2003, astro-ph/0301045.

[31]  G. Chapman.  Facular line profiles and facular models. , 1977 .

[32]  Eugene H. Avrett,et al.  Structure of the solar chromosphere. III. Models of the EUV brightness components of the quiet sun , 1981 .

[33]  S. Davis,et al.  The Signature of Solar Activity in the Infrared Spectral Irradiance , 2004 .

[34]  J. Fontenla.  Chromospheric plasma and the Farley-Buneman instability in solar magnetic regions , 2005 .

[35]  A. Hanslmeier,et al.  Center-to-Limb Variation of Facular Contrast Derived from MLSO RISE/PSPT Full Disk Images , 2005 .

[36]  P. Judge,et al.  Chromospheric and Transition Region Internetwork Oscillations: A Signature of Upward-propagating Waves , 2000 .

[37]  S. Walton.  Flux tube models of solar plages , 1987 .

[38]  Juan M. Fontenla,et al.  Energy Balance in the Solar Transition Region. II. Effects of Pressure and Energy Input on Hydrostatic Models , 1991 .

[39]  H. Neckel,et al.  The solar radiation between 3300 and 12500 Å , 1984 .

[40]  Thomas R. Ayres,et al.  Observations of Solar Carbon Monoxide with an Imaging Infrared Spectrograph. I. Thermal Bifurcation Revisited , 1996 .

[41]  G. Thuillier,et al.  The Solar Spectral Irradiance from 200 to 2400 nm as Measured by the SOLSPEC Spectrometer from the Atlas and Eureca Missions , 2003 .

[42]  H. Spruit.  Pressure equilibrium and energy balance of small photospheric fluxtubes , 1976 .

[43]  B. Caccin,et al.  Comparison of model calculations and photometric observations of bright magnetic regions , 2004 .

[44]  C. Korendyke,et al.  The Sources of Solar Ultraviolet Variability between 2765 and 2885 Å: Mg I, Mg II, Si I, and Continuum , 2001 .

[45]  E. F. Dishoeck,et al.  OH and CH continuous opacity in solar and stellar atmospheres , 1987 .

[46]  H. Neckel,et al.  Solar limb darkening 1986–1990 (λλ303 to 1099 nm) , 1994 .

[47]  P. Judge,et al.  SUMER Observations of the Quiet Solar Atmosphere: The Network Chromosphere and Lower Transition Region , 1997 .

[48]  M. Carlsson,et al.  Formation of Solar Calcium H and K Bright Grains , 1997 .

[49]  P. Maltby,et al.  The temperature of penumbral filaments , 1974 .

[50]  A. Skumanich,et al.  A model of a sunspot chromosphere based on OSO 8 observations , 1982 .

[51]  C. Keller,et al.  On the Origin of Solar Faculae , 2004 .