A Short Introduction to SPECTRUM

SPECTRUM ((C) Richard O. Gray, 1992-2008) is a stellar spectral synthesis program which runs on a number of platforms, including most flavors of UNIX and LINUX . It will also run under Windows 9x/XP/NT/2000/(VISTA?) using the Cygwin tools or the distributed Windows binaries. The code for SPECTRUM has been written in the "C" language. SPECTRUM computes the LTE synthetic spectrum given a stellar atmosphere model. SPECTRUM can use as input the fully blanketed stellar atmosphere models of Robert Kurucz including the new models of Castelli and Kurucz, but any other stellar atmosphere model which can be cast into the format of Kurucz's models can be used as well.

SPECTRUM can be programmed with "command-line switches" to give a number of different outputs. In the default mode, SPECTRUM computes the stellar-disk-integrated normalized-intensity spectrum, but in addition, SPECTRUM will compute the absolute monochromatic flux from the stellar atmosphere or the specific intensity from any point on the stellar surface.

SPECTRUM and a number of auxiliary programs can be run under batch mode, making automated computation of a large number of synthetic spectra possible.

SPECTRUM is distributed with an atomic and molecular line list for the optical spectral region 3000 A to 6800 A, called luke.lst, suitable for computing synthetic spectra for stars with effective temperatures between about 4500K and 20,000K. Further line lists in the ultraviolet, the near infrared and the infrared (out to 4 microns) are also available.

SPECTRUM currently supports all naturally occuring atomic elements, including 308 isotopes, and their first and in most cases second ions, and for specific elements, the third and fourth ions. SPECTRUM also supports the following diatomic molecules (including a number of isotopic versions): H2, CH, NH, OH, MgH, SiH, CaH, SiO, C2, CN, CO and TiO. Other molecules and ions will be added in the future.