J/A+A/639/L12 Search for NLTE modeling for classical nova ejecta (Shore+, 2020)
NLTE modeling and spectroscopically derived abundances of lithium and beryllium
for classical nova ejecta.
Shore S.N., De Gennaro Aquino I.
<Astron. Astrophys. 639, L12 (2020)>
=2020A&A...639L..12S 2020A&A...639L..12S (SIMBAD/NED BibCode)
ADC_Keywords: Models, atmosphere ; Spectroscopy ; Novae
Keywords: novae, cataclysmic variables - Galaxy: abundances -
nuclear reactions, nucleosynthesis, abundances -
methods: numerical
Abstract:
Extreme super-solar abundances of lithium and beryllium have been
reported in recent years for classical novae based on absorption lines
in ultraviolet and optical spectra during the optically thick stages,
but these findings have not been compared with spectrum syntheses of
the ejecta.
We present a grid of nova ejecta models calculated with PHOENIX aimed
at simulating the reported LiI and BeII features with super-solar
abundances.
We computed a sequence of models, finely exploring the parameter space
of effective temperature, ejecta expansion velocity, and Li and Be
overabundances.
Regardless of temperature and expansion velocity, the synthetic
spectra for large Li and Be overabundances strongly disagree with
those presented in recent literature. Assuming a wide range of Be
overabundances (factors of 100 to 10 000 relative to solar), we
predict a much stronger spectroscopic feature at BeII 3130Å than
those so far observed. A similar overabundance for Li would instead
result in a barely observable change in the emitted flux at LiI
6709Å. The observed extended absorption feature at 3131Å
reported in V838 Her and other novae appears even in zero-Be models
with only solar abundances (which for novae are underestimates).
The computed spectra do not support the lithium and beryllium
abundances, and caution is warranted in the interpretation of the
phenomenology.
Description:
We present a grid of NLTE nova ejecta models calculated with PHOENIX
aimed at simulating the reported LiI and BeII features with
super-solar abundances. Assuming a wide range of Be
overabundances, (factors of 100 to 10000 relative to solar), we
predict a much stronger spectroscopic feature at BeII 3131Å than
those so far observed. A similar overabundance for Li would instead
result in a barely observable change in the emitted flux at LiI
6709Å. The computed spectra do not support the lithium and
beryllium abundances and caution is warranted in the interpretation of
the phenomenology.
Sequence of NLTE models, covering the range of velocities and
effective temperatures exploring the parameter space of effective
temperature, ejecta expansion velocity, and Li and Be overabundances
for the wavelength range 10-10000Å.
File naming convention: CN_NLTE: Clasical nova non-LTE
_Luminosity (solar)
EffectiveTemperature,
Maximumvelocity (km/s)
_log (Be/Be_sun)
EX: CNNLTEL=50e3LsunTeff=15000V0=100LiBe=+00.00spec.7
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 80 46 List of spectra
sp/* . 46 Individual spectra
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 Lsun Lum [50000] Luminosity
7- 11 I5 K Teff [10000/20000] Effective temperature
13- 16 I4 km/s V0 [100/3500] Maximum velocity
18- 23 F6.2 [Sun] logBe Be abundance, in solar unit
25- 80 A56 --- FileName Name of the spectrum file in subdirectory sp (1)
--------------------------------------------------------------------------------
Note (1): File naming convention:
CN_NLTE: Clasical nova non-LTE
_Luminosity (solar)
EffectiveTemperature,
Maximumvelocity (km/s)
_log (Be/Be_sun)
Ex: CNNLTEL=50e3LsunTeff=15000V0=100LiBe=+00.00spec.7
--------------------------------------------------------------------------------
Byte-by-byte Description of file: sp/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
5- 25 E21.15 0.1nm lambda Wavelength
32- 45 E14.6 [mW/m2/cm] Flux Common logarithmic scaled monochromatic flux
52- 65 E14.6 [mW/m2/cm] Planck Common logarithmic Planck function
--------------------------------------------------------------------------------
Acknowledgements:
Steven N. Shore Kopylov, steven.neil.shore(at)unipi.it
(End) S.N. Shore Kopylov [Univ. of Pisa, Italy], P. Vannier [CDS] 24-Jun-2020