J/A+A/669/A76 Red supergiants synthetic spectra (Gonzalez-Tora+, 2023)
The effect of winds on atmospheric layers of red supergiants.
I. Modelling for interferometric observations.
Gonzalez-Tora G., Wittkowski M., Davies B., Plez B., Kravchenko K.
<Astron. Astrophys. 669, A76 (2023)>
=2023A&A...669A..76G 2023A&A...669A..76G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, supergiant ; Models ; Spectroscopy
Keywords: stars: atmospheres - stars: massive - stars: evolution -
stars: fundamental parameters - stars: mass-loss
Abstract:
Red supergiants (RSGs) are evolved massive stars in a stage preceding
core-collapse supernova. The physical processes that trigger mass loss
in their atmospheres are still not fully understood, and they remain
one of the key questions in stellar astrophysics. Based on
observations of alpha Ori, a new semi-empirical method to add a wind
to hydrostatic model atmospheres of RSGs was recently developed. This
method can reproduce many of the static molecular shell (or
'MOLsphere') spectral features.
We used this method of adding a semi-empirical wind to a MARCS model
atmosphere to compute synthetic observables, comparing the model to
spatially resolved interferometric observations. We present a case
study to model published interferometric data of HD 95687 and V602 Car
obtained with the AMBER instrument at the Very Large Telescope
Interferometer (VLTI).
We computed model intensities with respect to the line-of-sight angle
(mu) for different mass-loss rates, spectra, and visibilities using
the radiative transfer code TURBOSPECTRUM. We were able to convolve
the models to match the different spectral resolutions of the VLTI
instruments, studying a wavelength range of 1.8-5um corresponding
to the K, L, and M bands for GRAVITY and MATISSE data. The model
spectra and squared visibility amplitudes were compared with the
published VLTI/AMBER data.
The synthetic visibilities reproduce observed drops in the CO, SiO,
and water layers that are not shown in visibilities based on MARCS
models alone. For the case studies, we find that adding a wind onto
the MARCS model with simple radiative equilibrium dramatically
improves the agreement with the squared visibility amplitudes as well
as the spectra, with the fit being even better when applying a steeper
density profile than predicted from previous studies. Our results
reproduce observed extended atmospheres up to several stellar radii.
This paper shows the potential of our model to describe extended
atmospheres in RSGs. It can reproduce the shapes of the spectra and
visibilities with a better accuracy in the CO and water lines than
previous models. The method can be extended to other wavelength bands
for both spectroscopic and interferometric observations. We provide
temperature and density stratifications that succeed, for the first
time, in reproducing observed interferometric properties of RSG
atmospheres.
Description:
Tables produced with Turbospectrum v19.1 (Plez B., 2012) the user is
refereed to https://ascl.net/1205.004 for more information.
Indicating in the title:
temperaturemasslossyeartauspacingvelocitytempprofileluminosity_/
masswminwmaxmicroturbulencemuvalues
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 147 8 List of synthetic spectra
sp/* . 8 Individual synthetic spectra
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Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 K Teff [3500] Effective temperature
6- 11 E6.2 Msun/yr Mass-loss [1.0E-7/1.0E-4] Mass loss
13- 16 I4 yr Year [2022] Year produced
18- 21 F4.2 --- deltatau [0.05] delta (tau)
23- 24 I2 km/s Vmax [25] Maximum velocity of the wind
26- 29 A4 --- ProfT [HARP RAD] Temperature profile: Harper or RAD
31- 33 F3.1 [Lsun] logL [4.8] Luminosity
35- 36 I2 Msun Mass [15] Mass
38- 48 A11 0.1nm Range Wavelenght range of the spectra (18000-50000)
50- 52 F3.1 km/s xi [2] Microturbulence velocity
54- 56 I3 --- Nmu [164] Number of values of mu
58-147 A90 --- FileName Name of the file in subdirectory sp
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Byte-by-byte Description of file: sp/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.3 0.1nm lambda Wavelength
15- 22 F8.5 --- F/Fc Flux/Flux_continuum
25- 35 E11.5 --- Flux Flux (in cgs unit)
40-4303 164A26 --- SetI Intensity Intensity/I_continuum in cgs for
specific mu value (1)
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Note (1): Format E11.6 2X E11.6 2X.
Set of Intensity Intensity/I_continuum for mu=
1.0, 0.999, 0.998, 0.997, 0.996, 0.995, 0.994, 0.993, 0.992, 0.991,
0.9805699999999999, 0.96114, 0.9417150000000001, 0.92229, 0.90286, 0.88343,
0.864005, 0.84458, 0.82515, 0.80572, 0.786295, 0.76687, 0.7474400000000001,
0.72801, 0.708585, 0.68916, 0.6697299999999999, 0.6503, 0.6308750000000001,
0.61145, 0.59202, 0.57259, 0.553165, 0.53374, 0.51431, 0.49488,
0.47545499999999996, 0.45603, 0.4366, 0.41717, 0.41690499999999997, 0.41664,
0.416405, 0.41617, 0.41596, 0.41575, 0.41555, 0.41535, 0.41514, 0.41493,
0.41461000000000003, 0.41429, 0.41318, 0.41207, 0.410625, 0.40918,
0.40659999999999996, 0.40402, 0.401775, 0.39953, 0.39773000000000003, 0.39593,
0.394265, 0.3926, 0.390955, 0.38931, 0.38763000000000003, 0.38595,
0.38417500000000004, 0.3824, 0.380555, 0.37871, 0.37683500000000003, 0.37496,
0.37306, 0.37116, 0.369225, 0.36729, 0.36533499999999997, 0.36338, 0.3614,
0.35942, 0.35741, 0.3554, 0.353345, 0.35129, 0.34919, 0.34709, 0.34493,
0.34277,0.34054, 0.33831, 0.336005, 0.3337, 0.33130000000000004, 0.3289,
0.3264, 0.3239, 0.321275, 0.31865, 0.315895, 0.31314, 0.310235, 0.30733,
0.304265, 0.3012, 0.297955, 0.29471, 0.291285, 0.28786, 0.28425500000000004,
0.28065, 0.27686, 0.27307, 0.26910999999999996, 0.26515, 0.261015, 0.25688,
0.252575, 0.24827, 0.24379499999999998, 0.23932, 0.23467500000000002, 0.23003,
0.225205, 0.22038, 0.21536, 0.21034, 0.20511000000000001, 0.19988, 0.19443,
0.18898, 0.18328, 0.17758, 0.17162, 0.16566, 0.159435, 0.15321, 0.146715,
0.14022, 0.13349, 0.12676, 0.11987500000000001, 0.11299, 0.1060665, 0.099143,
0.0923585, 0.085574, 0.0791245, 0.072675, 0.066747, 0.060819, 0.055545,
0.050271, 0.04571, 0.041149, 0.037294499999999994, 0.03344, 0.030238,
0.027036, 0.0244095, 0.021783, 0.019646, 0.017509
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Acknowledgements:
Gemma Gonzalez-Tora, Gemma.GonzaleziTora(at)eso.org
(End) Patricia Vannier [CDS] 02-Nov-2022