J/A+A/676/A18 Modeling the Mg I from the NUV to MIR. II. (Peralta, 2023)
Modeling the Mg I from the NUV to MIR. II. Testing stellar models.
Peralta J.I., Vieytes M.C., Mendez A.M.P., Mitnik D.M.
<Astron. Astrophys. 676, A18 (2023)>
=2023A&A...676A..18P 2023A&A...676A..18P (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics
Keywords: atomic data - line: formation - stars: late-type - line: profiles
Abstract:
We present a new atomic model for MgI that that encompasses and improves
upon the model presented in Peralta et al. (2022A&A...657A.108P 2022A&A...657A.108P) for
the Sun. We test our model on three stars through their populations
and spectral lines. The distribution of Mg between ionization states
for stars with different effective temperatures was compared. For the
Sun and Epsilon Eridani, MgII predominates with more than 95 %, while
for GJ 832 and GJ 581, MgI with more than 72%. Moreover, in the
latter two, the amount of magnesium forming molecules in their
atmosphere is at least 2 orders higher. Regarding the NLTE population,
a noticeable lower variability in the departure coefficients was
found, indicating a better population coupling for the new model. A
comparison of the synthetic spectrum calculated between the older and
new MgI atomic model shows minimal differences in the visible range,
but stronger in the IR for all the stars. This aspect should be taken
into account when using lines from this region as indicators.
Nevertheless, some changes with the spectral type were found,
emphasizing also the need to test the atomic models in different
atmospheric conditions. In the FUV and NUV the most noticeable changes
occurred, obtaining a higher flux for the new atomic model, regardless
of the spectral type. The new model did not prevent the formation of
the core emission in the NUV line 2853Å. However, by including
other observations we could note that the emission indeed exists,
although with a much lower intensity. Further tests showed that to
reduce the emission, the population of its upper level (3s3p 1P)
should be reduced by a factor of about 0.01.
Description:
The tables are part of the SQL database that the SSRPM uses to
calculate both the atomic populations in NLTE and the synthetic
spectra.
'mgi_term.dat' contains the energy levels of the terms. Although it
contains superlevels from level 55 onwards, built according to Peralta
et al. (2022A&A...657A.108P 2022A&A...657A.108P), it is based on the data provided by NIST
(Kramida et al., 2004, https://physics.nist.gov/asd).
'mgi_ecs.dat' provides the Effective Collision Strengths (ECS) for the
collisional transitions in the NLTE calculation. 'CCC' are the data
calculated through convergent close-coupling by Barklem et al.
(2017A&A...606A..11B 2017A&A...606A..11B), and covers transitions up to level 25. From
level 26 to 85, 'DW' means that the calculations were carried out by
us through the multi-configuration Breit-Pauli distorted-wave
method.
'mgi_aij.dat' provides the Einstein Coefficients (s-1) for the
radiative transitions in the NLTE calculation. 'AS' referers to data
computed by us using the AUTOSTRUCTURE code (Badnell, 2011, Comput.
Phys. Commun., 182, 1528), and includes transitions between
superlevels. 'NIST' are data extracted from the NIST database
(Kramida et al., 2004, https://physics.nist.gov/asd).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
mgi_term.dat 23 85 MgI Atomic structure used in NLTE computations
mgi_ecs.dat 33 49680 MgI Effective Collision Strengths (CCC+DW)
mgi_aij.dat 47 3001 MgI Einstein Coefficients to compute NLTE (AS+NIST)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: mgi_term.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- LevelNum [1/85] Level (terms) Number for the Mg I model
4- 13 A10 --- FullConfig Full Configuration
15- 23 F9.3 cm-1 Level Level energy
--------------------------------------------------------------------------------
Byte-by-byte Description of file: mgi_ecs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- LowerLev [1/84] Lower Level number
4- 5 I2 --- UpperLev [2/85] Upper Level number
7- 13 F7.1 K T [500/20000] Temperature
15- 29 E15.10 --- ECS [0/49429227.85] Effective Collision Strengths
31- 33 A3 --- Source Source of the data (CCC or DW) (1)
--------------------------------------------------------------------------------
Note (1): Source as follows:
CCC = data calculated through convergent close-coupling by Barklem et al.
(2017A&A...606A..11B 2017A&A...606A..11B), and covers transitions up to level 25
DW = calculations were carried out by us through the multi-configuration
Breit-Pauli distorted-wave method
--------------------------------------------------------------------------------
Byte-by-byte Description of file: mgi_aij.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.4 0.1nm lambda [1629.57/60096123.0] Wavelength in Angstroms
15- 36 E22.17 s-1 Aij [0/965772032] Einstein Coefficient
38- 39 I2 --- LowerLev [1/84] Lower Level number
41- 42 I2 --- UpperLev [2/85] Upper Level number
44- 47 A4 --- Source Source of the data (AS or NIST) (1)
--------------------------------------------------------------------------------
Note (1): Source as follows:
AS = data computed by us using the AUTOSTRUCTURE code (Badnell, 2011, Comput.
Phys. Commun., 182, 1528), includes transitions between superlevels
NIST = data extracted from the NIST database (Kramida et al., 2004,
https://physics.nist.gov/asd)
--------------------------------------------------------------------------------
History:
From Juan Ignacio Peralta, jip1985(at)hotmail.com
Acknowledgements:
This work has made use of the VALD database, operated at Uppsala
University, the Institute of Astronomy RAS in Moscow, and the
University of Vienna. We acknowledge to 1995 Atomic Line Data (R.L.
Kurucz and B. Bell) Kurucz CD-ROM No. 23. Cambridge, Mass.:
Smithsonian Astrophysical Observatory
References:
Peralta et al., 2022A&A...657A.108P 2022A&A...657A.108P, Paper I
Fontenla et al., 2016ApJ...830..154F 2016ApJ...830..154F
Tilipman et al., 2021ApJ...909...61T 2021ApJ...909...61T
Vieytes & Peralta, 2021BAAA...62...92V 2021BAAA...62...92V
Fontenla et al., 2015ApJ...809..157F 2015ApJ...809..157F
Barklem et al., 2017A&A...606A..11B 2017A&A...606A..11B
(End) Patricia Vannier [CDS] 13-Feb-2023