PHOENIX
This submodule (BolometricCorrections.YBC.PHOENIX) enables interaction with the "YBC" bolometric correction (BC) grid calculated from PHOENIX model atmospheres as described in section 3.2 of Chen et al. (2019). The original atmosphere models are hosted by SVO here and StSCI provides a subset of the PHOENIX library for use with their Synphot software here.
In the original YBC implementation, the PHOENIX models are used for cool stars $T_e < 5500$ K and transition smoothly onto the ATLAS9 models from $5500 < T_e < 6500$ K. YBC specifically uses the BT-Settl set of PHOENIX models for which the main reference is Allard et al. (2012). The coverage of the model grid is fairly large – the full range of dependent variables covered by this grid is given in the table below.
| min | max | |
|---|---|---|
| Teff | 2,570 K | 70,794 K |
| logg | -0.5 | 6.0 |
| [Fe/H] | -4.0 dex | 0.5 dex |
| Av | 0.0 mag | 20.0 mag |
| Rv | 3.1 | 3.1 |
The full grid of unique values for the dependent variables is available in BolometricCorrections.YBC.PHOENIX.gridinfo.
using BolometricCorrections
keys(BolometricCorrections.YBC.PHOENIX.gridinfo)(:logTeff, :logg, :MH, :Av, :Rv)
Types
BolometricCorrections.YBC.PHOENIX.PHOENIXYBCGrid — TypePHOENIXYBCGrid(grid::AbstractString)Load and return the YBC PHOENIX bolometric corrections for the given photometric system grid, which must be a valid entry in BolometricCorrections.YBC.systems. This type is used to create instances of PHOENIXYBCTable that have fixed dependent grid variables ([M/H], Av). This can be done either by calling an instance of PHOENIXYBCGrid with (mh, Av) arguments or by using the appropriate constructor for PHOENIXYBCTable.
julia> grid = PHOENIXYBCGrid("acs_wfc")
YBC PHOENIX bolometric correction grid for photometric system YBC/acs_wfc.
julia> grid(-1.01, 0.11) # Can be called to construct table with interpolated [M/H], Av
YBC PHOENIX BT-Settl bolometric correction table with for system YBC/acs_wfc with [M/H] -1.01 and V-band extinction 0.11
julia> chemistry(grid) isa BolometricCorrections.MIST.MISTChemistry # Same chemical mixture as MIST
trueBolometricCorrections.YBC.PHOENIX.PHOENIXYBCTable — TypePHOENIXYBCTable(grid::PHOENIXYBCGrid, mh::Real, Av::Real)Interpolates the YBC PHOENIX bolometric corrections in grid to a fixed value of [M/H] (mh) and V-band extinction (Av), leaving only Teff and logg as dependent variables (the YBC PHOENIX BCs have only one Rv value). Returns an instance that is callable with arguments (Teff [K], logg [cgs]) to interpolate the bolometric corrections as a function of temperature and surface gravity.
PHOENIXYBCTable(grid::AbstractString, mh::Real, Av::Real)Loads the data necessary to construct the BC table for the provided grid (e.g., "acs_wfc") at [M/H] = mh and V-band extinction Av. This method does not support interpolation in metallicity or extinction, so the arguments mh and Av must be among the values provided by PHOENIX (see BolometricCorrections.YBC.PHOENIX.gridinfo.MH).
julia> grid = PHOENIXYBCGrid("acs_wfc")
YBC PHOENIX bolometric correction grid for photometric system YBC/acs_wfc.
julia> table = PHOENIXYBCTable(grid, -1.01, 0.011) # Interpolate table from full grid
YBC PHOENIX BT-Settl bolometric correction table with for system YBC/acs_wfc with [M/H] -1.01 and V-band extinction 0.011
julia> length(table(2755, 0.01)) == 12 # Returns BC in each filter
true
julia> size(table([2755, 2756], [0.01, 0.02])) # `table(array, array)` is also supported
(12, 2)
julia> using TypedTables: Table # `table(Table, array, array)` will return result as a Table
julia> table(Table, [2755, 2756], [0.01, 0.02]) isa Table
true
julia> chemistry(table) isa BolometricCorrections.MIST.MISTChemistry # Same chemical mixture as MIST
true
julia> PHOENIXYBCTable("acs_wfc", -2.0, 0.5) isa PHOENIXYBCTable # Can construct without a PHOENIXYBCGrid
trueSee here for a list of the photometric systems available that can be used as input arguments to PHOENIXYBCGrid and PHOENIXYBCTable.
Chemistry
These models use solar chemical abundances from Asplund et al. (2009), the same as MIST, so we use the same chemistry type to represent the PHOENIX chemistry (see here for more information).
chemistry(PHOENIXYBCTable)BolometricCorrections.MIST.MISTChemistry()Allard et al. (2013) discusses alternative BT-Settl models with the solar chemical composition from Caffau et al. (2011), YBC uses the models with Asplund et al. (2009) abundances.
PHOENIX References
This page cites the following references:
- Allard, F.; Homeier, D. and Freytag, B. (2012). Models of very-low-mass stars, brown dwarfs and exoplanets. Philosophical Transactions of the Royal Society of London Series A 370, 2765–2777, arXiv:1112.3591 [astro-ph.SR].
- Allard, F.; Homeier, D.; Freytag, B.; Schaffenberger, W. and Rajpurohit, A. (2013). Progress in modeling very low mass stars, brown dwarfs, and planetary mass objects. Memorie della Societa Astronomica Italiana Supplementi 24, 128, arXiv:1302.6559 [astro-ph.SR].
- Asplund, M.; Grevesse, N.; Sauval, A. J. and Scott, P. (2009). The Chemical Composition of the Sun. Annual Review of Astronomy and Astrophysics 47, 481–522.
- Caffau, E.; Ludwig, H.-G.; Steffen, M.; Freytag, B. and Bonifacio, P. (2011). Solar Chemical Abundances Determined with a CO5BOLD 3D Model Atmosphere. Solar Physics 268, 255–269.
- Chen, Y.; Girardi, L.; Fu, X.; Bressan, A.; Aringer, B.; Dal Tio, P.; Pastorelli, G.; Marigo, P.; Costa, G. and Zhang, X. (2019). YBC: a stellar bolometric corrections database with variable extinction coefficients. Application to PARSEC isochrones. A & A 632, A105, arXiv:1910.09037 [astro-ph.SR].