| Format of the spectra output files |
In this catalogue you will find the precomputed grids of synthetic spectra.
The model atmopsheres and synthetic spectra ARE ONLY adressing the PHOTOSPHERE and do not include parts of the atmosphere which are not governed by hydrostatic equilibrium such as chromospheres and corona for stars or exospheric evaporation in the case of irradiated planets or stars.
The simulator uses the most recent code version to generate as close as possible spectra compatible with the published grids i.e. by adopting the same parameters (mixing length, geometry of the radiative transfer, opacities for the most important when possible). No attemps has been made to reproduce those older results exactly.
Reference of solar abundance.
Reference of water vapor line list.
The model assumption: Local Thermodynamic Equilibrium (LTE) or non-LTE.
The effective temperature (Teff).
The surface gravity (log10g).
The metallicity by log10 number density with respect to solar values ([M/H]).
The alpha element enhencement relative to solar values ([alpha/H]).
The model grid name codes different models used.
The BT and AMES in the names of the grids refer to the source of water vapor line list used in these models (BT stands for the Barber & Tennyson BT2 2006 line list, while AMES stands for the Partridge & Schwenke 1997 line list). The NextGen models used the preliminary water vapor line list by Schryber, Miller & Tennyson 1995. There is four different types of models below: the NextGen appellation is reserved for pure gas phase equilibrium models, the Dusty appellation refers to models in which dust is formed is equilibrium with the gas phase (maximum dust content), the Cond appellation refers to Dusty models is which the dust opacity has been neglected to simulated a minimum dust content case, and finally the Settl appelation refers to models accounting for dust formation via a paramater-free cloud model (base on the work by Rossow 1978). Relative to Dusty models, the latter models include among other microphysical processes, gravitational settling, which explains the choice of the Settl label for these models.
With a cloud model, valid across the entire parameter range (GNS1993, AGSS2009 & CIFIST2011)
Allard et al. '03, Allard et al. '07, Allard et al. '09, Allard et al. '10, Allard et al. '11, Allard et al. '12a,b, Allard et al. '13
Same as AMES-Dusty with updated opacities (only CIFIST2011 available)
Allard et al. '09, Allard et al. '10, Allard et al. '11, Allard et al. '12
Same as AMES-Cond with updated opacities (only CIFIST2011 available)
Allard et al. '09, Allard et al. '10, Allard et al. '11, Allard et al. '12
Same as NextGen with updated opacities (only CIFIST2011 available)
Allard et al. '09, Allard et al. '10, Allard et al. '11, Allard et al. '12
Dust in equilibrium with gas phase, (only GNS1993 available) "valid" for Near-IR studies with Teff > 1700 K
Allard et al. '01, Chabrier et al. '00
Same as AMES-Dusty with dust opacities ignored, (only GNS1993 available) "valid" for Teff< 1400 K
Allard et al. '01, Baraffe et al. '03
Gas phase only, valid for Teff > 2700 K (only GNS1993 available)
Allard et al. '97, Baraffe et al. '97, Baraffe et al.'98, Hauschildt et al. '99
These models are provided for different solar abundance values from different authors when available. CIFIST2011 stands for the Caffau et al. (2011) values. AGSS2009 stands for the values by Asplund et al. (2009). GAS2007 stands for the Grevesse, Asplund & Sauval (2007) values. And GNS1993 stands for the original Grevesse, Noels & Sauval (1993) values. However, the model grids do not differ by only the source of solar abundances, but represent the Phoenix code development status (opacities, cloud model) at the time of computation.
Indication of output file format.
The file name of the spectra output.
The pre-computed grids of spectra are provided in ascii format (*.7.gz):
Additional columns, obtained systematically when computing spectra using the Phoenix simulator, give the information to identify atomic and molecular lines. This information is used by the idl scripts lineid.pro and plotid.pro which are provided in the user result package.
With the stacked ascii format (*.spec.gz files) we have rather:
DF= -8.d0 for all most recent models (Ergs/sec/cm2/cm). For older model series like the NextGen and AMES-Cond grids DF= -26.9007901434d0, because previous Phoenix outputs were giving out the luminosity, L (= R2 * H) in erg/s/cm2/cm. And for NextGen spectra of effective temperature 5000K and above, DF'= -28.9007901434d0.
A very important point is that since models are often computed on parallel computers using several nodes, it is important to sort the spectra files in increasing wavelength order prior to using them.
Please note that a convertion of the fluxes to absolute fluxes as measured at the earth requires a multiplication by the dilution factor (radius/distance)2. The distance cancels out when accounting simultaneously for the dilution factor and distance modulus at 10 pc (for absolute magnitudes for instance). This is done using the following formula:
Note that Phoenix delivers synthetic spectra in the vaccum and that a line shift is necessary to adapt these synthetic spectra for comparisons to observations from the ground. For this, divide the vacuum wavelengths by (1+1.e-6*nrefrac) as returned from the function below to get the air wavelengths (or use the equation for AIR from it).
def nrefrac(wavelength, density=1.0):
"""Calculate refractive index of air from Cauchy formula.
Input: wavelength in Angstrom, density of air in amagat (relative to STP,
e.g. ~10% decrease per 1000m above sea level).
Returns N = (n-1) * 1.e6.
"""
# The IAU standard for conversion from air to vacuum wavelengths is given
# in Morton (1991, ApJS, 77, 119). For vacuum wavelengths (VAC) in
# Angstroms, convert to air wavelength (AIR) via:
# AIR = VAC / (1.0 + 2.735182E-4 + 131.4182 / VAC^2 + 2.76249E8 / VAC^4)
try:
if isinstance(wavelength, types.ObjectType):
wl = np.array(wavelength)
except TypeError:
return None
wl2inv = (1.e4/wl)**2
refracstp = 272.643 + 1.2288 * wl2inv + 3.555e-2 * wl2inv**2
return density * refracstp
Download a native text file with precomputed grids of model atmosphere synthetic spectrum from PHOENIX archive in text format.
Download a precomputed model atmosphere synthetic spectrum in the FITS format, which is generated on fly.
Plot a precomputed model atmosphere synthetic spectrum.
Dispay the FITS header.
This field contains wget command to retrive FITS file of the given model. To prepare the list of wget commands it is necessary 1) to select only "wget" field in the menu, 2) to choice "Formatted text" as output and 3) to click on "Submit" button.
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