J/A+A/627/A46 Sunspot penumbra and umbral flashes models (Bose+, 2019)
Semi-empirical model atmospheres for the chromosphere of the sunspot penumbra
and umbral flashes.
Bose S., Henriques V.M.J, van der Voort L.R., Pereira T.M.D.
<Astron. Astrophys. 627, A46 (2019)>
=2019A&A...627A..46B 2019A&A...627A..46B (SIMBAD/NED BibCode)
ADC_Keywords: Models, atmosphere ; Sun
Keywords: Sun: atmosphere - Sun: chromosphere - Sun: transition region -
sunspots - radiative transfer
Abstract:
The solar chromosphere and the lower transition region are believed to
play a crucial role in the heating of the solar corona. Models that
describe the chromosphere (and the lower transition region),
accounting for its highly dynamic and structured character are, so
far, found to be lacking. This is partly due to the breakdown of
complete frequency redistribution (CRD) in the chromospheric layers
and also because of the difficulty in obtaining complete sets of
observations that adequately constrain the solar atmosphere at all
relevant heights. We aim to obtain semi-empirical model atmospheres
that reproduce the features of the MgII H & K line profiles that
sample the middle chromosphere with focus on a sunspot. We used
spectropolarimetric observations of the CaII 8542Å spectra obtained
with the Swedish 1-m Solar Telescope and used NICOLE inversions to
obtain semi-empirical model atmospheres for different features in and
around a sunspot. These were used to synthesize MgII H & K spectra
using the RH1.5D code, which we compared with observations taken with
the Interface Region Imaging Spectrograph (IRIS). Comparison of the
synthetic profiles with IRIS observations reveals that there are
several areas, especially in the penumbra of the sunspot, where most
of the observed MgII H & K profiles are very well reproduced. In
addition, we find that supersonic hot downflows, present in our
collection of models in the umbra, lead to synthetic profiles that
agree well with the IRIS MgII H & K profiles, with the exception of
the line core. We put forward and make available four semi-empirical
model atmospheres. Two for the penumbra, reflecting the range of
temperatures obtained for the chromosphere, one for umbral flashes,
and a model representative of the quiet surroundings of a sunspot.
These are available in electronic as well as in table formats.
Description:
The tables included in this paper describes the stratification of
atmospheric parameters for the cool and the hot penumbra, umbral flash
and the quiet surrounding respectively as a function of geometric
height and optical depth.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
hot.dat 84 150 Model atmospheres for the hot penumbra
cool.dat 84 150 Model atmospheres for the cool penumbra
uf.dat 84 150 Model atmospheres for the umbral flash
qs.dat 84 150 Model atmospheres for the quiet Sun
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Byte-by-byte Description of file: uf.dat cool.dat hot.dat qs.dat
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Bytes Format Units Label Explanations
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3- 8 F6.3 [-] logtau Log of the optical depth at 5000 Angstroem
11- 18 F8.3 km Height Geometrical height
21- 28 F8.2 K Temp Temperature
31- 38 F8.2 m/s Vlos Line-of-sight velocity (1)
41- 48 F8.2 m/s Vmic Microturbulent velocity (1)
52- 60 E9.3 m-3 NH Total Hydrogen density
64- 72 E9.3 m-3 Ne Electron density
76- 84 E9.3 kg/m3 Den Gas density
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Note (1): Defined following the usual Astrophysical convention, in which
negative (positive) velocities are towards (away from) the observer.
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Acknowledgements:
Souvik Bose, souvik.bose(at)astro.uio.no
(End) Souvik Bose [UiO, Norway], Patricia Vannier [CDS] 03-Jun-2019