J/A+A/624/A36 EUV irradiances of the quiet Sun (Del Zanna, 2019)
The EUV spectrum of the Sun: Quiet- and active-Sun irradiances and
chemical composition.
Del Zanna G.
<Astron. Astrophys. 624, A36 (2019)>
=2019A&A...624A..36D 2019A&A...624A..36D (SIMBAD/NED BibCode)
ADC_Keywords: Sun ; Solar system ; Ultraviolet
Keywords: Sun: abundances - Sun: corona - Sun: UV radiation -
line: identification - techniques: spectroscopic
Abstract:
We benchmark new atomic data against a selection of irradiances
obtained from medium-resolution quiet-Sun spectra in the extreme
ultraviolet (EUV), from 60 to 1040Å. We used as a baseline the
irradiances measured during solar minimum on 2008 April 14 by the
prototype (PEVE) of the Solar Dynamics Observatory Extreme ultraviolet
Variability Experiment (EVE). We took into account some
inconsistencies in the PEVE data, using flight EVE data and
irradiances we obtained from Solar and Heliospheric Observatory (SoHO)
Coronal Diagnostics Spectrometer (CDS) data. We performed a
differential emission measure and find overall excellent agreement (to
within the accuracy of the observations, about 20%) between predicted
and measured irradiances in most cases, although we point out several
problems with the currently available ion charge-state distributions.
We used the photospheric chemical abundances of Asplund et al.
(2009ARA&A..47..481A 2009ARA&A..47..481A). The new atomic data are nearly complete in this
spectral range for medium-resolution irradiance spectra. Finally, we
used observations of the active Sun in 1969 to show that the
composition of the solar corona up to 1MK is nearly photospheric in
this case as well. Variations of a factor of 2 are present for
higher-temperature plasma, which is emitted within active regions.
These results are in excellent agreement with our previous findings.
Description:
Within the UK APAP network (www.apap-network.org), we have carried out
several large-scale structure and scattering R-matrix calculations
over the past few years to produce atomic data for dozens of ions (see
the review in Badnell et al., 2016JPhB...49i4001B 2016JPhB...49i4001B).
For the assessment here, we use CHIANTI v.8 as a baseline, together
with a few minor changes that are being released within CHIANTI v.9
(Dere et al., 2019, ApJ, submitted) and a large set of new atomic data
that have been prepared for CHIANTI v.10 (Del Zanna et al., in
preparation).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 50 391 EUV irradiances of the quiet Sun
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See also:
VI/152 : SOVAP-PICARD total solar irradiance (Meftah+, 2016)
J/ApJ/789/117 : Solar spectral irradiance (Marchenko+, 2014)
J/A+A/581/A26 : Solar Lyman irradiance line profiles (Lemaire+, 2015)
J/other/SoPh/291.3527 : SOLAR/SOLSPEC UV SSI from 2008-2015 (Meftah+, 2016)
J/A+A/611/A1 : SOLAR/SOLSPEC Spectral Irradiance - 0.5-3000nm
(Meftah+, 2018)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 0.1nm lambda Observed wavelength
9- 14 F6.3 10+8ph/cm2/s/arcsec Iobs Measured irradiance
16- 19 F4.2 [K] logTmax Maximum effective temperature
21- 24 F4.2 [K] logTeff Effective temperature
26- 29 F4.2 --- R Ratio between the predicted and
observed irradiance values
31- 36 A6 --- Ion Main contributing Ion
38- 45 F8.3 0.1nm lambadExp Ion CHIANTI wavelength
47- 50 F4.2 --- r Fractional contribution
to the blend
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Acknowledgements:
Giulio Del Zanna, gd232(at)hermes.cam.ac.uk
(End) Patricia Vannier [CDS] 01-Apr-2019