The type parameter allows to select from a range of stellar models, either analytical, or available as data files or FITS images. Please note that a new numbering scheme was introduced with Version 6.12 (2 Aug 2007)
For all types from zero to 11, the flux distribution (spectrum)
is computed as flat (teff=0), a black body (teff < 0),
or derived from a stellar atmosphere (teff > 0). For all types,
specifying an arbitrary SED will override stellar spectra or fluxes
derived from the images. The XDR file to read is specified in sed,
and should restore variables and
, which contain the wavelength
in meters and the flux (per wavelength interval), respectively. Please
note that if the effective of a component is non-zero, the flux will be
scaled with the squared diameter! As mentioned above (readmodel),
please keep in mind that an internal value of
for an effective
temperature is interpreted as zero.
Stellar spectra and limb-darking coefficients as a function of log(g) and teff are from Van Hamme (1993) and are stored in file atmospheres/vanhamme/limbdata.vh.xdr. For stellar temperatures less than 3500 K it is possible to use the NextGen models (http://phoenix.ens-lyon.fr/Grids/) by copying one of the files atmospheres/vanhamme/limbdata.n?.xdr to limbdata.xdr. Please note that the NextGen models do not provide the limb-darkening coefficients! Further information can be found in the file Notes.txt.
In many models, specifying pa and ratio is used to rotate
and stretch the coordinates. The only exceptions are the images
if a positive non-zero diameter of the CLEAN beam have been specified.